Term
| What is Lennox-Gastaut Syndrome? |
|
Definition
a form of childhood onset epilespy that most often appears between the second and sixth year of life.
It is often accompanied by mental retardation and behavior problems. |
|
|
Term
| What is status epilepticus? |
|
Definition
More than 30 minutes of continuous seizure activity OR two or more sequential seizures spanning this period without full recovery or normal alertness in between.
It is a medical emergency as it can cause hypoxic cerebral damage or metabolic complications. |
|
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Term
| What is the mechanism of action of phenytoin? What are some other drugs in this class? |
|
Definition
Phenytoin slows the rate of recovery of voltage activated Na+ channels from inactivation. This limits the repetitive firing of action potentials.
Other drugs: fosphenytoin, carbamazepine, oxcarbezepine, valproic acid, lamotrigine |
|
|
Term
| How do benzodiazepines and barbituates improve epilepsy symptoms? |
|
Definition
| These drugs (i.e. phenobarbital, primidone, diazepam, clonazepam) potentate the synaptic action of GABAa receptors and allow more Cl- ions to enter the neuron and hyperpolarize it. This makes the action potential less likely. |
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Term
What is the mechanism though to be associated with absence seizures?
What drugs are effective in treating these types of seizure? |
|
Definition
Current through T-type Ca2+ channels in thalamic neurons are thought to be responsible for absence seizures.
Ethosuximide and valproic acid reduce the current through these Ca2+ channels and reduce the incidence of the seizures. |
|
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Term
| Why is primidone effective as an anti-convulsant? |
|
Definition
| It is metabolized to phenobarbital and phenylethylmalonamide. All three are active anticonvulsants. |
|
|
Term
| What is the treatment for status epilepticus? |
|
Definition
| lorazepam or diazepam iv followed in 30 minutes by phenytoin or fosphenytoin. If that is not successful than phenobarbital. |
|
|
Term
| What are some side effects of phenytoin? |
|
Definition
blocks Na+ channels.
shows saturation kinetics
SE: confusion, teratogenesis, gum hyperplasia, skin rash, anemia, many other drug interactions |
|
|
Term
| What is the bulbocavernosus reflex? |
|
Definition
When pulling on the glans of the penis or an indwelling foley catheter causes a reflex contraction of the anal sphincter muscle.
It is S2-S4 mediated.
Lack of sacral trauma can indicate spinal shock. It is one of the first reflexes to return after spinal shock. lack of sensory and motor return indicates a complete SCI |
|
|
Term
| What is the oculocephalic reflex? |
|
Definition
The Doll's eye reflex. Normally when a head is moved quickly to one side, then the eyes will compensate to remain looking in the original direction.
If there are problems with the vestibular system then the the eyes will turn with the head (positive doll's eye). |
|
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Term
| What are the initial measures to be taken after CNS trauma. |
|
Definition
1. load anticonvulsants/antiepileptics i.e. levetiracetam and phenytoin.
2. antibiotics (broad) i.e. vancomycin and ceftriaxone
3. mannitol when rapid deterioration or signs of herniation
4. rapid CT |
|
|
Term
| what is mannitol used for? |
|
Definition
manitol is a osmotic diuretic that is used to reduce ICP by reducing extracellular volume.
It is given during rapid deterioration of CNS trauma patients and also when there are signs of herniation. |
|
|
Term
| When do you admit for mild head injury patients |
|
Definition
mild head injury=14-15
admit if:
1.no CT or abnormal CT
2. penetrating injury
3. LOC
4. intoxicated
5. no reliable companion |
|
|
Term
| During a severe head injury, if SBP does not respond to fluids, what should be done? |
|
Definition
DPL (diagnostic peritoneal lavage), abd U/S and ex lap to check where there is bleeding.
Also place an ICP moniter. |
|
|
Term
| What is the monro-kellie doctrine? |
|
Definition
The brain is a closed space. Pressure comes from CSF, blood, brain tissue and cerebral perfusion pressure.
The cranial compartment is incompressible. So an increase in any of the constituents much be compensated by a decrease in volume of another.
Usually an increase in lesion volume i.e. hematoma can be compensated for by displacement of CSF or venous blood.
CPP(cerebral perfusion pressure)=MAP(mean arterial pressure)-ICP(intracranial pressure) |
|
|
Term
| What the indications for ICP monitering? |
|
Definition
1. pt with GCS<8 and abnormal CT.
2. GCS<8 with normal CT scan if age >45, motor posturing or SBP<90
3. treat ICP> 20-25mmHG to keep CPP up. |
|
|
Term
| What are the treatments for ICP? |
|
Definition
preemptive:
1. HOB at 30 degrees
2. PaCo2 35-40 mmHG
3. Euvolemia
4. seizure prophylaxis
5. sedation
6. CPP>70
After the fact:
1. CSF drainage from ventriculostomy
2. mannital to serum Osm <320
3. hypertonic saline to serum Na<170
4. pentobarbitol to place in coma. |
|
|
Term
| what is subfalcine herniation? |
|
Definition
| (cingulate) unilateral expanding mass forces midline structures across the falx. ACAs can be occluded leading to bilateral leg weakness |
|
|
Term
|
Definition
mass in the middle cranial fossa causes the medial portion of the hippocampal gyrus between the tentorium and midbrain.
CNS III palsy and hemiparesis if the cerebral peduncle get compressed.
Eventually compression of PCA= loss of contralaterl visual field. |
|
|
Term
|
Definition
| bihemispheric lesions causes bilateral posterior herniation of temporal lobes. Causes bilateral ptosis and loss of upward gaze. |
|
|
Term
|
Definition
| downward cerebellar=sudden apnea because of compression of brainstem. |
|
|
Term
| What is the lucid interval associated with epidural hematomas? |
|
Definition
| around 50% of patients become unconcious after the initial concussion. Then they wake up and behave normally. Then as ICP increases due to the increasing size of the hematoma, there is rapid deterioration due to increased ICP. |
|
|
Term
| What are the management choices for EDH? |
|
Definition
1. surgical drainage: coagulate source, look for SDH if dura appears tense or blue.
2. obliterate epidural space to minimize recurrence.
2. observe with serial neuro exam if there are minimal neuro deficits, minimal midline shift (less than 3mm) and EDH less than 10mm. |
|
|
Term
|
Definition
| loading stresses from high rates of acceleration and deceleration. |
|
|
Term
| What are the treatment choices for ASDH |
|
Definition
surgical drainage if:
1. SDH>1cm
2. GCS<8, SDH>5mm, MLS >5mm
3. GCS 9-13, SDH 5mm-1cm, declining LOC and focal deficits
-consider resection of pulped cortex
2. observe if
-minimal neuro deficits
-minimal midline shift
-SDH<10mm |
|
|
Term
|
Definition
sudural hematomas that are at least 2 weeks old. SDH occurs as a vascularizd membrane around clot which can rehemorrhage easily.
mostly in the elderly. |
|
|
Term
| What are the treatment options for chronic subdural hematoma? |
|
Definition
if >1cm
1. twist drill
2. burr holes
3. craniotomy |
|
|
Term
| what is the post op care for CSDH? |
|
Definition
1.flat bedrest
2.elevate HOB slowly
3. maintain euvolemia
4. maximize nutrition
5. anticonvulsant levels
6. be on lookout for ICH, acute SDH and tension pneumocephalus(air can get in during surgey esp burr drill because of pressure differences). |
|
|
Term
| What are the conditions for surgical reseciton of an intracerebral hematoma? |
|
Definition
-IH>2cm
-IH<2cm with effacement of basal cisterns, >5mm MLS
-expectant treatment of IH in eloquent cortex
-do not operate on basal ganglia or internal capsule hematomas.
25% of patients recover fully regardless of management. |
|
|
Term
| What are the indications for skull fracture repair? |
|
Definition
1. depression greater than thickness of skull
2. underlying area of brain compressed with deteriorating function
3. CSF leakage
4. cosmetics |
|
|
Term
| What physical findings can be found with skull base fractures? |
|
Definition
- CSF rhinorrhea or otorrhea
- hemotympanum
-battle's sign
-raccoon eyes.
facial nerve palsy occurs with temporal bone fractures.
1. longitudinal (along EAC) disrupt ossicles resulting in deafness.
2. transverse fractures are perpendicular to EAC. CN V, VI, VII or VIII plasy in 50% of cases.
all CN VII palsy treated initially with steroids. |
|
|
Term
| What are diffuse axonal injuries? |
|
Definition
diffuse axonal injuries occur during severe acceleration or deceleration i.e. in a MVA. This causes axonal disruption.
axon bulbs form in lobar white matter at the gray white junction, CC and upper brainstem.
initial CT normal but petichial hemorrhage may be seen.
Outcome is usually coma. Most severe DAI patients never wake up. |
|
|
Term
| How do you tell the difference between a conus medullaris spinal injury and a cauda equina spinal cord injury. |
|
Definition
| Both SCIs produce paralysis i nthe limbs. However conus medullaris injuries will usually be symmetric while cauda equina injuries will be asymmetric. |
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|
Term
| What is the difference between primary demyelination and secondary demyelination? |
|
Definition
Primary demyelination=intrinsic defect or injury to oligodendrocytes
secondary= myelin loss and/or destruction following and axonal injury |
|
|
Term
| Distinguish between myelinoclastic disorders and leukodystrophies |
|
Definition
leukodystrophies=due to mutations in genes responsible for myelin metabolism or maintenence e.g. krabbe's
myelinoclastic disorders=acquired e.g. autoimmune, nutritional deficiencies, toxins and infections |
|
|
Term
| Where to MS plaques usually form in the cerebral cortex? |
|
Definition
| In the angles of the lateral ventricle, optic nerve and can also occur in the grey matter. |
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|
Term
| MS plaques have very discrete borders and three stages. Name and describe how these stages would appear histologically |
|
Definition
active plaques=densely cellular with lots of lymphocytes, foamy macrophages and a few astrocytes
inactive plaques=paucicellular, densely gliotic, depleted oligodendrocytes, reduced axon number and axonal atrophy. May cavitate.
Shadow plaques= myelin reduced by not absent. remyelinated axons have thin myelin sheath. starts weeks after demyelination. shadowy because of sporadic remyelination. |
|
|
Term
| What is the clinical presentation of acute disseminated encephalomyelitis? What patient population is it more likely to affect? |
|
Definition
ADEM is a group of immune mediated demyleinating disorders that are more common in children and adolescents. related to febrile illness of vaccination.
There is aseptic meningitis, motor involvement, cranial nerve dysfunction, fever and headache. |
|
|
Term
| What is characteristic about the histology of acute disseminated encephalomyelitis? |
|
Definition
small distended veins surrounded by foamy macrophages and lymphocytes. (sleeve like zone around veins)
also petechial hemorrhages and herniation due to edema may occur. |
|
|
Term
| What is subacute combined degeneration (of the spinal cord)? |
|
Definition
disease resulting from a B12 deficiency, though to result from defective protein methylation (MBP).
patients have parasthesiae of lower limbs, loss of fine touch, vibration and position sense.
progresses to spastic paraparesis, ataxia and anesthesia |
|
|
Term
| What is the pathology of subacute combined degeneration of the spinal cord. |
|
Definition
macro=spinal cord shows slightly shrunken, discolored posterior and lateral columns especially in lower cervical and thoracic regions
micro=myelin loss and vacuolation. eventually gliosis and axonal degeneration. |
|
|
Term
| What is central pontine myelinolysis? Where is it seen? What neurological deficits does it result in? |
|
Definition
-monophasic demyelination seen with rapid correction of hyponatremia, extensive skin burns, alcoholics with liver disease.
-see limb muscle weakness, confusion, gaze palsies, dysarthria, dysphagia and hypotension can often be fatal |
|
|
Term
| What neuropathology is seen in central pontine myelinolysis? |
|
Definition
macro-base pons has central gray discolored region and may be asymmetric
micro= active demyelination with reactive astrocytes and lipid laden macrophages. |
|
|
Term
What is progressive multifocal leukoencephalopathy?
How do patients present? |
|
Definition
PML= infection by polyomavirus i.e. JC or BK of the oligodendrocytes
healthy people get silent infection, only manifests in immunocomprimised patients.
patients present with focal neurologic defecits over months and impairments get more severe. |
|
|
Term
| What is the neuropath of PML? |
|
Definition
-white matter shows small focal gray areas that can become large and confluent and necrotic.
micro=foamy macrophages, but few lymphocytes. oligos have nuclear inclusions. |
|
|
Term
What type of disorder is Krabbe's disease?
How does it present? |
|
Definition
lysosomal storage disease and a leukodystrophy.
-onset in infancy, failure to thrive, vomiting, lack of motor and social development+ blindness, optic atrophy and neuropathy.
death in 1 to 2 years. |
|
|
Term
What type of disorder is Krabbe's disease?
How does it present? |
|
Definition
lysosomal storage disease and a leukodystrophy.
-onset in infancy, failure to thrive, vomiting, lack of motor and social development+ blindness, optic atrophy and neuropathy.
death in 1 to 2 years. |
|
|
Term
| What is the neuropathy of Krabbe's disease? |
|
Definition
macro= atrophy of intragyral white matter and wide sulci.
micro-loss of myelin and oligodendrocytes. pathognomonic globoid macrophages |
|
|
Term
| globoid macrophages are pathogonomic for? |
|
Definition
|
|
Term
| What is metachromatic leukodystrophy? |
|
Definition
lysosomal storage disorder.
presents 1 to 2 years of age with atxia, spasticity and absent deep tendon reflexes in lower limbs. optic atropy and seizures as well. most die by 3 |
|
|
Term
| What is the neuropath of metachromatic leukodystrophy? |
|
Definition
macro- normal, large or atrophic brain. white matter is firm and can be chalky
micro-demyelination with extensive axonal loss. cresyl violet stain=brown stain because of accumulation of sulfatide in tissues. |
|
|
Term
| What is adrenaleukodystrophy? |
|
Definition
A peroxisomal disorder. symptoms vary by age of presentation
infant-hypotonia, seizure, failure to thrive
child-loss of skills, school problems
adult-dementia and schizophrenia
VERY LONG CHAIN FATTY ACIDS ACCUMULATE IN TISSUES |
|
|
Term
| what is the neuropath of adrenaleukodystrophy? |
|
Definition
macro- caudorostral progression with severe myeline loss in posterior although U-fibers are spared
micro- severe demyelination in central cerebral white matter and commisures. See an advancing edge, with lymphocytes early and foamy macrophages late. |
|
|
Term
| What other pathology is associated with adrenaleukodystrophy? |
|
Definition
| adrenal cortex cells ballon due to lipid accumulation. striated cytoplasm is seen. |
|
|
Term
| What is Tay-Sachs disease? |
|
Definition
-lysosomal storage disease
-infants are normal for first few months at about 8 months fail to acquire skills, seizures and EASILY STARTLED. |
|
|
Term
| What is the neuropathology associated with Tay-Sachs disease? |
|
Definition
Ballooned neurons.
also on ophatlmic exam there can be degeneration of macular retinal ganglion cells that expose underlying vascular choroid=whitish ring |
|
|
Term
| What is muccopolysaccharidoses? |
|
Definition
| A leukendystrophy that is AR or X-linked. Can result in skeletal deformities. |
|
|
Term
| what is the neuropath of mucopolysaccharidoses? |
|
Definition
macro-obstructive hydrocephalus, spinal cord compression. also see white rings around brain vessels
micro= ganglioside accumulation in neurons (not the mucopolysaccharides) |
|
|
Term
| What is the neuropath of alzheimer's disease? What area of the brain does it affect? |
|
Definition
| cortical atrophy, wide sulci and thin gyri. The occipital region is more likely to be spared. |
|
|
Term
| With dementia with Lewy bodies, were is the most severe atrophy seen? |
|
Definition
| In the limbic areas. There is also neuronal loss in the substantia nigra and locus ceruleus. |
|
|
Term
| What type of disease is Hungtington's diseaase? |
|
Definition
| trinucleotide repeat disorder. chorea, rigidity and cognitive disturbances are observed |
|
|
Term
| Where is brain atrophy seen in Hungtington's disease? |
|
Definition
|
|
Term
| What are the 3 cardinal features of PD? |
|
Definition
| Bradykinesia, resting tremor, rigidity |
|
|
Term
| What is spinocerebellar ataxia? |
|
Definition
-large group of autosomal dominant trinucleotide repeat disorders
-all show signs of cerebellar ataxia |
|
|
Term
| What is Friedrich's Ataxia? |
|
Definition
-Trinucleotide repeat disorder
-Patients often less than 15 years old
-starts with gait then limb ataxia, dysarthria. also loss of position/vibration sense in legs, leg weakness and areflexia. |
|
|
Term
| What causes Friedrich's Ataxia, what kind of neuropathology is observed? |
|
Definition
-TRD. mitochondrial iron transport is regulated by frataxin (coded for by gene with Trinucleotide repeat). This leads to neuron damage.
neuropath=posterior column degeneration although corticospinal tract and clarke's column can also be involved |
|
|
Term
| How does ALS present pathologically |
|
Definition
Degeneration of upper and lower motor neurons.
Anterior roots are smaller than posterior roots and anterior horn will show degeneration as well. |
|
|
Term
| What factors affect the prevalence of diabetic retinopathy? |
|
Definition
1. age of onset
2. duration of disease
3. degree of diabetes control
4. hypertension |
|
|
Term
| What are the fundascopic findings for early nonproliferative diabetic retinopathy? |
|
Definition
| -microaneurysms=abnormal endothelial cells that lack tight junctions that leak serum and products |
|
|
Term
| What are the fundascopic findings for advanced nonproliferative diabetic retinopathy |
|
Definition
1. cotton wool spots=nerve fibers are edamatous
2. intraretinal microvascular abnormalities
3. venous beating |
|
|
Term
| What is the treatment for advanced nonproliferative diabetic retinopathy? |
|
Definition
| -no immediate treatment, high risk of imminent PDR, patient needs to be re-evaluated in 2-4 months |
|
|
Term
| What are the fundascopic findings for proliferative diabetic retinopathy? |
|
Definition
-macular edema
-NEOVASCULARIZATION of disc and retina
-vitreous hemorrhage
-fibrous proliferatino with retinal detachment |
|
|
Term
| What causes vision loss in PDR? |
|
Definition
-macular edema
-vitreous hemorrhage
-traction retinal detachment |
|
|
Term
| What are the symptoms of maculopathy? |
|
Definition
-gradual progressive loss of central vision
-vision is "smeared", "oily", "filmy" or dirty glasses
-central scotoma(alteration in visual field) |
|
|
Term
| When is maculopathy treated? |
|
Definition
-When there is retinal edema within 1/3 disc diameter from the center of the fovea
-hard exudate within 1/3 DD associated with edema
-edema greater than 1 DD in area within 1 DD from fovea |
|
|
Term
| What are the symptoms of proliferative diabetic retinopathy? |
|
Definition
-floaters and cobwebs
-rapid dramatic vision loss
-visual field loss |
|
|
Term
| When is proliferative diabetic retinopathy treated? |
|
Definition
| -NVD or NVE with preretinal bleeding |
|
|
Term
| What is the treatment for vitreous hemorrhage and traction retinal detachment? |
|
Definition
|
|
Term
| What are the symptoms of vitreous hemorrhage? |
|
Definition
| floaters, cobwebs and streaks. vitreous can become opaque. fundascopic exam reveals cloudy vitreous |
|
|
Term
| What is the treatment for NVD and NVE proliferative diabetic retinopathy? |
|
Definition
pan retinal photocoagulation
-1000-2000 laser burns over several sessions to get rid of new blood vessels.
SE=decreased night vision, decreased peripheral vision, decreased central vision |
|
|
Term
| Why is good lipid control necessary to limit diabetic retinopathy? |
|
Definition
| -decrease the amount of lipid exudate from microhemorrhages |
|
|
Term
| How does anemia affect retinopathy risk? |
|
Definition
anemia=significant effects on retina, Hgb<12gms=2x risk for retinopathy. increased risk of macular edema.
low hematocrit is an independent risk factor for developing PDR. |
|
|
Term
| What is the treatment for macular edema? |
|
Definition
-treat with fluorescein angiography
-focal laser coagulation of microaneurysms
-grid laser to areas of retinal edema and non-perfusion |
|
|
Term
| What is the treatment for macular edema? |
|
Definition
-treat with fluorescein angiography
-focal laser coagulation of microaneurysms
-grid laser to areas of retinal edema and non-perfusion |
|
|
Term
| What are the screening guidelines for type 1 diabetes? |
|
Definition
| 5 years after the duration of diabetes. follow up exam yearly. |
|
|
Term
| What are the screening guidelines for type 2 diabetes? |
|
Definition
initial consult at time of diagnosis.
follow up yearly. |
|
|
Term
| What is the difference between epilepsy and a seizure? |
|
Definition
epilepsy is a disease characterized by spontaneous recurrence of unprovoked seizures.
seizures are symptoms that result form abnormal and involuntary rhythmic neuronal discharges in the cerebral cortex. |
|
|
Term
What is a hyperexcitable neuron?
What is hypersynchrony? |
|
Definition
Tendency for a neuron to discharge repetitively to a stimulus that normally evokes only a single action potential
hypersynchrony is the tendency of a group of neurons to discharge together. |
|
|
Term
| What defines a simple partial seizure? |
|
Definition
| SPS are not associated with loss of consciousness because they begin in a small area of the brain. Only one neurlogical modality is affected. |
|
|
Term
| what defines a complex partial seizure? |
|
Definition
complex partial seizures are associated with alteration but not loss of consciousness. The patient is awake but stares blankly and is not responsive to external stimuli.
Automatisms i.e. reptitive purposeless movements can accompany complex partial seizures i.e. lip smacking, chewing, swallowing, hand wringing. |
|
|
Term
| What defines a generalized seizure? |
|
Definition
| These seizures start throughout the entire cortex at the same time and cause loss of consciousness. There are eight type of generalized seizures. |
|
|
Term
| What are "grand mal" seizures also known as? |
|
Definition
Generalized Tonic-Clonic Seizures: begin with tonic phase of whole body stiffening followed by a clonic phase of repetitive contractions. These are followed by 2-3 minutes of confusion or complete unresponsiveness.
Any type of partial seizure may secondarily generalize into a generalized tonic-clonic seizure. |
|
|
Term
| What are myoclonic seizures? |
|
Definition
| Very brief lightening like muscular jerks. |
|
|
Term
| What are absence seizures? |
|
Definition
| "petit mal seizures" manifest as brief 1-10 second episodes of staring and unresponsiveness. They can sometimes be associated with eye blinking or oral or manual automatisms. EEG pattern is a 3 Hz spike and wave pattern. |
|
|
Term
| What is the difference between atypical absence seizures and absence seizures? |
|
Definition
| Similar but longer in duration and more motor involvement |
|
|
Term
| What are atonic seizures? |
|
Definition
| Seizures that manifest as a sudden loss in muscle tone followed by dropping to the floor unprotected. |
|
|
Term
| What are the EEG features of absence epilepsy? |
|
Definition
| 3Hz 3Hz spike and wave pattern |
|
|
Term
| What are the main inhibitory and excitatory neurotransmitters? |
|
Definition
GABA=inhibitory
Glutamate=excitatory |
|
|
Term
| What are the two types of GABA receptor and how do they affect the membrane potential within the neuron? |
|
Definition
| GABAa= inhibitory= ligand gated chloride channel. activation leads to an influx of chloride ion and the generation of an IPSP. anti-convulsants e.g. benzos and barbs increase the activity of this receptor. |
|
|
Term
| What are the three types of glutamate receptor? |
|
Definition
glutamate receptor= excitatory
AMPA= activation leads to influx of Na+ and depolarization.
NMDA= activation allows influx of Ca2+. Receptor is blocked by Mg+
metabotropic receptors=inhibits release of glutamate at presynaptic terminal. |
|
|
Term
| What are the diagnostic tests used for epilepsy? |
|
Definition
1. serological studies=determine provoking factors. also if already an epilepsy patient, you can determine side effects from AEDs.
2.EEG samples electrical activity from the brain.
3. neuroimagining= determine etiology of epilepsy and other life threatening conditions. |
|
|
Term
| What 3 roles does the EEG play in epilespy diagnosis? |
|
Definition
1. identify individuals that have a tendency to seizure due to epilepsy
2. suggest site of seizure onset
3. classify a patient's epilespy syndrome. |
|
|
Term
| How does vagus nerve stimulation improve epilepsy outcomes? |
|
Definition
| This device applies intermittent current from a pacemaker like device to the left vagus nerve. The left vagus nerve had projections to the nucleus solitarius tact and eventually locus cereuleus. This results in norepinephrine release and increased level of inhibitory GABA release. This reduces the levels of aberrant neuronal activity. |
|
|
Term
| what is the ketogenic diet? |
|
Definition
treatment offered to children with catastrophic epilepsy.
initiated by starvation in the hospital until urine contains moderate to large ketones.
maintained by providing calories almost exclusively through fat and protein with specific avoidance of carbohydrate. |
|
|
Term
| What is the proper treatment for mucocele in an infant? |
|
Definition
| May appear similar to nasolacrimal duct blockage but it is important not to massage cyst as it can result in cellulitis. TX with abx, may need surgical debridement. |
|
|
Term
| Hyperacute conjunctivitis in infants are usually caused by either staph, neisseria gonorrhea and chlamydia. How do you distinguish between these three? |
|
Definition
1. staph=gram positive cocci.
2. neisseria=gram negative. perforate membrane. TX with hospitalization and systemic antibiotics
3. chlamydia= giemsa stain distinguished from neisseria b/c intracellular parasite=inclusion bodies. or fluorescence. TX=topical erythromycin |
|
|
Term
At what ages does.
1. depth perception and binocular vision develop in children
2. the ability to fixate on objects
3. grasping of objects and good visual contact. |
|
Definition
1. 4 months (retina is not developed yet)
2. 3 months
3. 4 months |
|
|
Term
| What is strabismus? What test can you use to distinguish strabismus from pseudostrabismus? |
|
Definition
| Eye crossing. Use Hirschberg or corneal light reflex test to distinguish. If lateral to the pupil=esotropia if medial=exotropia |
|
|
Term
| What is the treatment for children with esotropia? |
|
Definition
|
|
Term
| What is the treatment for children with esotropia from ages 12 months to 48months? |
|
Definition
1. usually refractive error, in which case use corrective lens
2. if lens don't work then use surgery |
|
|
Term
| What is exotropia and what is the treatment? |
|
Definition
| Eyes, turning out. purely a motor problem and so can only be treated surgically. |
|
|
Term
|
Definition
Ambylopia is when vision in one eye is worse than the other eye (possibly due to strabismus or anisometropia)
best treated with patching the sound eye to force the usage of the bad eye. continue until 5-7. |
|
|
Term
|
Definition
| refractive error difference between eyes. |
|
|
Term
| What is blepharitis and what are the treatments? |
|
Definition
irritation or flakiness around eye lids
caused by either staph or yeast(malazzia). treat with better eye lid hygeine, lid scrubs, topical antibiotics. can spread to scalp etc. |
|
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Term
| What are the treatments for hemangiomas in children? |
|
Definition
1. nothing if benign, will go away
2. if will cause ptosis/astigmatism can treat with topical steroids or beta blockers. |
|
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Term
|
Definition
| benign self involuting tumors of endothelial cells |
|
|
Term
| What is the DDx of leukocoria? |
|
Definition
1. retinoblastoma
2. cataracts
3. retinal detachment
4. coats disease |
|
|
Term
| What are the treatments for retinoblastoma? |
|
Definition
1. if large enucleate eye
2. chemoreduction followed by laser
3. irradiation (not often used)
retinoblastoma=leukocoria
50% of retinoblastoma is sporadic.
50% is genetically related i.e. RB1=tumor suppressor gene. If born with one copy mutated, it is more likely that a somatic mutation will result in the disease. |
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|
Term
What is retinopathy of prematurity?
Tx |
|
Definition
appears in premature infants. retinal vascularization is incomplete, leaving peripheral retina non-vascuralized.
after birth after a child grows, new vessels can proliferate either normally or abnormally.
If abnormal then it can lead to traction retinal detachemnt
Tx=kill avascular retina with laser |
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|
Term
| What is radial keratotomy? |
|
Definition
| when radial cuts are made in the cornea in order to flatten the central cornea to treat myopia. |
|
|
Term
| What are the two etiologies of blepharoptosis? |
|
Definition
| 1. congenital=dystrophy of levator palpebrae superioris muscle, where the muscle fibers are replaced by noncontractile collagen. surgery=tighten levator muscle and link tarsal plate with frontalis muscle. |
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|
Term
| What are the two etiologies of blepharoptosis? |
|
Definition
1. congenital=dystrophy of levator palpebrae superioris muscle, where the muscle fibers are replaced by noncontractile collagen. surgery=tighten levator muscle and link tarsal plate with frontalis muscle.
2. acquired= usually involutional changes affecting the levator muscle aponeurosis. correct with surgery |
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|
Term
| What is entropian vs ectropion? |
|
Definition
entropian=inward turning of lid margin
ectotropian=outward turning of lid margin (can be related to facial palsy)
both require surgical intervention |
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Term
| What is a chalazion? Hordeolum? |
|
Definition
inflammation of the meibomian glands of the upper and lower eyelid.
hordeolum=acute chalazion due to infection of glands of zeis or meibomian glands.
Tx= warm compresess, topical antibiotics.
if chronic chalazion=surgically incise |
|
|
Term
| What are the attributes of a basal cell carcinoma? |
|
Definition
| -raised edges, extra vascularization, central ulceration, torturous superficial vessels and destruction of normal structures. |
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Term
|
Definition
| excess tears running over the lid margin |
|
|
Term
|
Definition
low grade infection that can result in nasolacrimal duct obstruction.
Tx=dacryocystorhinostomy. |
|
|
Term
| What is the treatment for orbital cellulitis? |
|
Definition
| CT scan of orbit and sinuses. admit into hospital for IV Abx. surgical drain of abcess if necessary. |
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Term
| How can you differentiate between preorbital and orbital cellulitis? |
|
Definition
preorbital=erythema of lid margin etc but no other symptoms
orbital=affect one of the ocular adnexae i.e. corneal edema, inhibition of ocular muscles, vision loss, abormal pupulliary reflex, proptosis |
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|
Term
| What are the distinct features of thyroid eye disease? |
|
Definition
1. retraction of eyelids
2. enlargment of extraocular muscles and impairment of mobility with diplolia
3. proptosis
4. possible visual damage with optic nerve compression |
|
|
Term
| What is the tx for thyroid eye disease? |
|
Definition
1. systemic corticosteroids
2. radiation therapy
3. orbital surgery to expand orbit. |
|
|
Term
What is the most common benign extraocular tumor in children?
adults? |
|
Definition
dermoid cyst=temproal or superior medial. superior medial may need surgical excision
cavernous hemangioma=only excise if symptomatic. |
|
|
Term
| What is the most common malignant orbital tumor for children? |
|
Definition
rhabdomyosarcoma=quick progression. may be mistaken for an infectious process.
biopsy and then irradiate with chemo |
|
|
Term
| What are the most common orbital tumors in adults? |
|
Definition
1. lymphoma=usually by itself, check and then treat with radiation
2. mets from lung or breast. chemo or rads depending |
|
|
Term
| What is the neuronal pathway for the sympathetic pathway to the ciliary dilator muscles? |
|
Definition
| posterior hypothalamus--->ciliospinal center of budge (C8-T1)--->superior cervical ganglion--->internal carotid to cavernous sinus and dilator pupillae muscle. |
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|
Term
| outline the 4 neuron system for the pupillary light reflex |
|
Definition
1. retina to pretectal nuclei as part of the optic tract
2. pretectal to edwinger westphal nucleus (BILATERAL)
3. EW nucleus parasympathetic fibers along CN III to ciliary ganglion
4. ciliary ganglion to iris sphincter muscles. |
|
|
Term
| What is the near reflex triad? |
|
Definition
1. accomadation
2. constriction
3. convergence |
|
|
Term
| What is the triad of symptoms for Horner's syndrome? |
|
Definition
disruption of sympathetic chain equals
1. miosis
2. ptosis
3. anhidrosis |
|
|
Term
| What is argyll-roberton pupils indicate? |
|
Definition
neurosyphillis=FTA-ABs test for treponema pallidum
pupils accomadate upon convergence but do not constrict with light |
|
|
Term
|
Definition
| retinal or optic nerve problems i.e. acute glaucoma, detached retinal, decreased visual acuity, central scotoma and nerve lesions anterior to the lateral geniculate. |
|
|
Term
| If Horner's syndrome presents with pain, what is the best course of action? |
|
Definition
| painful Horner's syndrome can be related to aortic dissection. stat MRI/ultrasound/angiogram. |
|
|
Term
| What are the symptoms of CN III palsy? What is the most worrisome diagnosis? |
|
Definition
1. ptosis
2. mydriasis
3. "down and out" eye
This could indicate a posterior communicating artery aneurysm pressing down on the nerve |
|
|
Term
What is the classic presentation of giant cell arteritis?
What tests would you order to confirm suspicions? |
|
Definition
older than 55 year old non african american
jaw claudication, scalp tenderness, sudden unexplained vision loss, polymyalgia, headache and diplopia.
Erythrocyte sedimentation rate and temporal artery biopsy |
|
|
Term
| What are the causes of papilledema? |
|
Definition
brain mass, ventricular system blockage, malignant htn, medications, increased CSF production.
GET A MRI/HEAD CT |
|
|
Term
| what type of brain lesion would produce bitemporal hemianopsia? |
|
Definition
|
|
Term
| where would a homonymous hemianopia lesion present? |
|
Definition
|
|
Term
| what type visual field defects can result from a pituitary adenoma ? |
|
Definition
| bitemporal quatrantopia (upper chromosome) |
|
|
Term
| What is the cause of corneal edema? |
|
Definition
| high ocular pressure drives fluid into the cornea causing colored rainbows around lights due to scatter. IOP usually due to glaucoma |
|
|
Term
| how do you distinguish a corneal abrasion versus a HSV infection? |
|
Definition
fluorescein dye and shine with cobalt blue versus another die.
HSV will look dendritic=admit |
|
|
Term
| What is the most common cause of acute vision loss in the anterior chamber? |
|
Definition
| hyphema. can use steroids, aminocaproic acid (to reduce bleeding), cycoplegics |
|
|
Term
| What are the two acute causes of cataracts? |
|
Definition
1.extremely high blood glucose levels due to uncontrolled diabetes
2. trauma |
|
|
Term
| What are the two acute causes of cataracts? |
|
Definition
1.extremely high blood glucose levels due to uncontrolled diabetes
2. trauma |
|
|
Term
| what are the causes of vitreous hemorrhage? |
|
Definition
| proliferative diabetic retinopathy. NO RAPD |
|
|
Term
| what are the vision loss inducing pathologies of the retina? |
|
Definition
1. diabetic retinopathy, both proliferative and nonproliferative
2. ARMD both wet and dry
3. CRAO and BRAO
4. CRVO
5. retinal detachment |
|
|
Term
| what are the treatments for ARMD? |
|
Definition
|
|
Term
| What is the presentation of central retinal artery occulsion? TX? |
|
Definition
white retina, cherry red spot (choroidal circulation seen behind macular region)
Tx=reduce IOP, find cardiac or carotid embolis source |
|
|
Term
| how does retinal detachment present? |
|
Definition
many floaters and lights followed by dark curtain falling over.
easily seen on opthalmic exam |
|
|
Term
| what are the causes of ischemic optic neuropathy? |
|
Definition
arteritic=giant cell arthritis
nonarteritic=diabetes or HTN |
|
|
Term
What are the three different etiologies for adult conjunctivitis?
How to distinguish? |
|
Definition
1. bacterial=purulent discharge, sticky, no preauricular node (except chlamydia). if chlamydia or gonorrhea=systemic antibiotics
2. allergic=stringy white discharge, itchy. use topical antihistamines
3. viral conjunctivitis=serous discharge, preauricular node, self limited
stay at home 10-14 days |
|
|
Term
| subconjunctival hemorrhage tx? |
|
Definition
| none, just reassure if it doesn't reoccur. |
|
|
Term
| What are the causes of dry eye syndrome? |
|
Definition
| -aging, RA, stevens-johnson, sys meds and sjogrens |
|
|
Term
| how can you treat dry eyes? |
|
Definition
| punctal occulusion, tears, lubrication ointment |
|
|
Term
| what are some tx for corneal abrasion? |
|
Definition
| cyclogyl 1%=anticholinesterase=cycloplegia and paralysis of pupillary sphincter b/c both are parasympathetic |
|
|
Term
| how does scleritis present and tx? |
|
Definition
boring pain that wakes up from sleep. associated with collagen vascular diseases
tx=steroids and nsaids |
|
|
Term
| what is the management of chemical burns? |
|
Definition
| irrigation to pH 7.0, 7.4 using saline, ringer's lactate or sterile water. use IV tubing and do for at least 30 minutes |
|
|
Term
| how does bacterial keratitis present? |
|
Definition
red painful eyes, purulent discharge with corneal opacity (keratitic precipites?)
decreased vision |
|
|
Term
| what are the side effects of topical steroids? |
|
Definition
-increase IOP,
-perforeate cornea
-cataracts
-fungal corneal ulcer |
|
|
Term
| For herpes zoster infection, what clue reveals if ocular there is ocular disease? |
|
Definition
| if there is herpes on tip of nose |
|
|
Term
| How is HSV keratitis different from most viral keratitis? |
|
Definition
-unilateral corneal involvment (most is bilateral)
dendritic pattern for fluorescein staining
tearing |
|
|
Term
| What are the treatments for HSV, HZV and misc viral keratitis? |
|
Definition
HSV=topical
HZV=systemic (topical if nose)
maybe steroids
misc=supportive only |
|
|
Term
| What are the signs and symptoms of iritis? |
|
Definition
-circumcorneal redness
-pain
-photophobia
-miotic pupil |
|
|
Term
| Where is aqueous humor produced and what are the two drainage mechanisms? |
|
Definition
Aqueous humor is produced by the ciliary processes through ultra filtration and active secretion of capillary blood.
80% fluid flows out of the pupil filters out of the trabecular meshwork into the canal of schlemm.
20% filters through the face of the ciliary muscle that is located at the base of the iris. |
|
|
Term
| What are some risk factors for open angle glaucoma? |
|
Definition
1. family history
2. african american ethnicity
3. thick cornea
4. age (increase above age 40)
5. increased C/D ratio |
|
|
Term
| What are the symptoms of open angle glaucoma? |
|
Definition
OAG can present for a very long time with no symptoms. As the disease progresses, there is loss of peripheral vision with preservation of normal visual acuity. Eventually central vision is destroyed.
Prognosis is good if caught early and vision can be maintained. However visual loss is irreplaceable. |
|
|
Term
| What are the optic nerve changes associated with open angle glaucoma? |
|
Definition
1. increased C/D ratio
2. vertical cupping
3. notching
4. disc hemorrhage |
|
|
Term
| What are the parameters used to diagnose open angle glaucoma? |
|
Definition
1.optic nerve changes
2. tonometry (IOP)
3. testing of peripheral visual field |
|
|
Term
| What are the four type of treatment for open angle glaucoma? |
|
Definition
1. exercise
2. medical treatment
3. laser surgery
4. surgical procedures |
|
|
Term
| What is the only oral medication used to treat open angle glaucoma? |
|
Definition
carbonic anhydrase=decrease aqueous production.
SE=decreased appetite, weight loss, malaise, kidney stones, rash, aplastic anemia |
|
|
Term
| Why can beta blockers be used to treat open angle glaucoma? |
|
Definition
they decrease aqueous productino
SE=exacerbation of asthma, bradycardia, heart block, impotence and depression |
|
|
Term
| What 4 topical medications can be used to treat open angle glaucoma? |
|
Definition
beta-blockers
alpha-2 agonists=decrease production and increase outflow
prostaglandins=increase uveoscleral outflow (can lead to change in eye color and increase eye lash length)
carbonic anhydrase=decrease aqueous production. SE=corneal swelling and skin rash |
|
|
Term
| What are some risks of laser surgery to treat glaucoma? |
|
Definition
| temporary increase in IOP |
|
|
Term
| What are the risks of trabeculectomy? |
|
Definition
-intraocular hemorrhage
-intraocular infection
-cataract formation
-scarring
-infection
-bleb |
|
|
Term
| What are the signs and symptoms of angle closure glaucoma? |
|
Definition
| seeing colored haloes around lights, decreased vision, ocular pain, vomitting |
|
|
Term
| What are the treatments for angle closure glaucoma? |
|
Definition
-laser iridectomy opens a communication between the posterior iris to fall back away from the trabecular meshwork and open the angle.
-pilocarpine=constrict pupil and ciliary muscle to also contract which opens the trabecular meshwork. |
|
|
Term
| How does angle closure glaucoma occur? |
|
Definition
occurs when the peripheral iris makes a less than 20 degree angle with the peripheral cornea.
As we age, the lens becomes thicker which results in resistance of aqueous flow from the posterior to the anterior chamber of the eye. This can push the peripheral iris forward and result in angle closure. |
|
|
Term
| What are the signs and symptoms of congenital glaucoma? |
|
Definition
enlarged eye/cornea, cloudy cornea, tearing, sensitivity to light and pain.
Because the infant eye has a higher elastic component, the increased IOP causes the eye to stretch and results in buphthalamos (ox eye) |
|
|
Term
| Why does the cornea become cloudy with congenital glaucoma? |
|
Definition
| with continued stretching of the eye, the descement membrane splits open, allowing aqueous to enter the cornea, resulting in cloudiness |
|
|
Term
| What is the treatment for congenital glaucoma? |
|
Definition
| surgical gonitomy, restoring outflow of aqueous |
|
|
Term
| What causes congenital glaucoma? |
|
Definition
| Abnormal development of the anterior chamber angle. |
|
|
Term
| What is secondary glaucoma? |
|
Definition
When trabecular outflow is blocked by an acquired ocular condition e.g. inflammation, intraocular hemorrhage and STEROIDS.
after a month of steroid use about 30% of the population will have increased IOP which should be measured. |
|
|
Term
| Where are lesions in MS usually found? |
|
Definition
| In the periventricular white matter. These sites are areas with a high concentration of venules which are vessels in which inflammatroy demyelination is likely to be associated? |
|
|
Term
| What are the four types of MS? |
|
Definition
1. Relapsing-remitting(most common)
2. Relapsing-remitting followed by secondary progressive
3. primary progressive (10%)
4 progressive relapsing (rare) |
|
|
Term
| What MRI imaging techniques can be used to produce better resolution of MS lesions? |
|
Definition
FLAIR= subtract fluid signal, so that it does not interfere with the visualization of periventricular lesions
T1 with Gd= postcontrast that can highlight disease activity=hypodense because of edema=active lesion. |
|
|
Term
|
Definition
| The name given to the distribution of the periventricular lesions. |
|
|
Term
| What are the 3 stages of MS lesion progression? |
|
Definition
1. active lesion=Gd enancing with inflammatory infiltrate
2. chronic active lesion= inflammatory activity around lesion edge but loss of myelin within boundary of the lesion
3. chronic inactive lesion=glial scarring and fibrosis |
|
|
Term
| What MRI lesions are predictive of MS in the future without any current symptoms? |
|
Definition
1. more than 3 white matter lesions on T2
2. more than 2 Gd-enhancing lesions
3. a new T2 or Gd enhancing lesion 3 months after a clinically isolated symptom. |
|
|
Term
| What lab tests can be useful in diagnosing MS. |
|
Definition
Lumbar puncture and oligoclonal bands in the CSF.
evoked potentials can also be used, but evidence points to low accuracy. |
|
|
Term
| What are the 9 symptoms that can be associated with MS? |
|
Definition
1. optic neuritis + Marcus Gunn pupil
2. ocular muscle dysfunction, most commonly INO
3. vestibular abnormalities and balance abnormalities
4. ambulation dysfunction
5. tremor
6. transient symptoms i.e. Lhermitte's sign, uhthoff phenomenon, trigeminal neuralgia
7. cognitive dysfunction
8. bladder and sexual dysfunction
9. bowel dysfunction |
|
|
Term
| What are the current treatments for MS? |
|
Definition
1. interferons (decrease incidence of symptoms and decrease number of new brain lesions)
2. glatiramer acetate- interupts the targeting of the immune system against CNS myelin
3. natalizumab (reduces the transmission of T lymphocytes through the BBB into the CNS, so there is less inflammation of the myelin)
4. mitoxantrone (immune suppression) |
|
|
Term
| What is the difference between neuromuscular blockers and spasmolytics? |
|
Definition
1. neuromuscular blockers are used to completely paralyze skeletal muscle during surgical procedures
2. spasmolytics are used to modulate muscle contraction and used in ambulatory patient |
|
|
Term
| What are the typical characteristics of a neuromuscular blocking drug? |
|
Definition
Usually bisquaternarny ammonium compounds (so always keep charge despite the environment).
interacts with Ach receptor in a one to one manner. |
|
|
Term
| What are the two classifications of neuromuscular blocking drugs? |
|
Definition
1. nondepolarizing blocking drugs
2. depolarizing blocking drugs |
|
|
Term
| How do nondepolarizing neuromuscular blocking drugs paralyze muscle? Give a few examples |
|
Definition
They are competitive blockers of Ach receptors at the NMJ.
Some examples include pancuronium, vecuronium etc anything with (-ium) |
|
|
Term
| How can the activity of nondepolarizing neuromuscular blockers be reversed? when doing this what is another important consideration? |
|
Definition
Increase the concentration of Ach at the NMJ because of competitive nature of inhibition. Use ChE inhibitor such as neostigmine, physostigmine or edrophonium.
Also include atropine to protect muscarinic receptors from over stimulation. |
|
|
Term
| Describe the pharmocologic progression of the succinylcholine response. |
|
Definition
divided into two phases
phase 1 block: succinylcholine binds to Ach receptor causing depolarization. Because succinylcholine is not broken down by Achesterases, it has a longer duration. NMJ is kept depolarized and Ach has no effect. Ca++ is resequestered into the sarcoplasmic reticulum resulting in flaccidity.
phase 2 block- receptor blockade takes on characteristics of nondepolarizing NMJ blockade.
end plate repolarization is possible due to confirmational change of receptor molecule |
|
|
Term
| What would a patient with liver failure show an increased response to succinylcholine? |
|
Definition
succinylcholine is metabolized in the plasma by plasma cholinesterase. This is produced in the liver. So liver dysfunction, decreased hepatic blood flow will cause prolonged responses to succinylcholine.
also neonates and genetic disposition to lower plasma ChE.
treat with mechanical respirations. |
|
|
Term
| What are some adverse affects to neuromuscular drugs in general? |
|
Definition
| 1. do no enter brain so CNS is fully functional and pain is not dulled. therefore if a patient wakes up during a surgery, they are paralyzed but feel full pain. |
|
|
Term
| What are some adverse affects for depolarizing NMJ blockers? |
|
Definition
fasciculations result in
-post operative muscle stiffness and pain
-increase in introcular pressure due to contraction of extraocular muscles
-increased intragastric pressure
-hyperkalemia |
|
|
Term
| what are some adverse effects of the nondepolarizing NMJ blocker atracurium? |
|
Definition
release of endogenous histamine into the circulation=bronchospasm, increased exertions, vasodilations.
treat with antihistamines. |
|
|
Term
| What is malignant hyperthermia and what is the treatment? |
|
Definition
A genetic disorder triggered by the use of halogenated anesthetic or succinylcholine.
This causes a sudden rise in Ca++ in muscle fiber with an increase in body temperature.
treat with dantroline! |
|
|
Term
What is the mechanism of action for Dantroline?
what is a side effect? |
|
Definition
interferes with the release of Ca2+ from the sarcoplasmic reticulum which is required for muscle contraction.
can use for SCI, stroke, cerebral palsy, MS
potential toxicity=hepatotoxic |
|
|
Term
| What is the activity of baclofen? |
|
Definition
Baclofen is a centrally acting spasmolytic.
It is a GABAb receptor agonist. It activates the GABAb receptors on neurons that release excitatory neurotransmitters onto motor neurons. |
|
|
Term
| What is the activity of diazepam? |
|
Definition
| Benzodiazepine. enhances the actions of inhibitor neurotransmitter GABA in the spinal cord. |
|
|
Term
| What is the structure of a local anesthetic drug? |
|
Definition
Consist of an aromatic part (lipophilic) linked by either an ester or amide to a based side chain (hydrophilic).
Esters are more prone to hydrolysis than amides and therefore have a shoter duration of action. |
|
|
Term
| What is the mechanism of action for local anesthetics? |
|
Definition
local anesthetics block action potential generation by blocking voltage gated Na+ channels. This prevents nerve repolarization.
They show use-dependece because the anesthetic molecules gain access to the channels more readily when the channels are open.
duration of action can be increased if used in conjunction with a vasoconstrictor such as epinephrine or phenyephrine. |
|
|
Term
| How do you distinguish between amide and ester bonded local anesthetics? |
|
Definition
| amides have an 'i' before the caine. usually have a longer duration as well |
|
|
Term
| What are the side effects of local anesthetics? |
|
Definition
side effects=escape into systemic circulations
CNS effects= agitation, confusion, tremor progessing to convulsions
cardio=myocardial depression and vasodilation
intra-articular infusions=chondrolysis |
|
|
Term
| What type of nerves are most susceptible to local anesthetic block? |
|
Definition
| Nerves with less myelination will be the most susceptible to local anesthetic as this give more membrane exopsure. i.e. dorsal root and sympathetic nerves. dorsal root=pain+sensation. |
|
|
Term
| What are the clinical features of myopathy? (as opposed to neuropathy) |
|
Definition
1. weakness begins proximally and is symmetric
2. muscles are often preserved or enlarged
3. muscle may be tender or indurated
4. with muscle percussion, there is diminished muscle contraction
5. reflexes are present by parallel the degree of muscle strength. |
|
|
Term
What are the symptoms of Duchenne muscular dystrophy?
What is the cause? |
|
Definition
Symptoms appear in early childhood. Patients are described as toe walking, waddling gait, excessive lumbar lordosis and muscle hypertrophy (especially the calves). Lose ambulation by 10-12, respiratory insufficiency by 20.
Caused by mutation in dystrophin gene at Xp21, which is involved in the dystrophin-glycoprotein complex.
X-linked recessive |
|
|
Term
| What is limb-girdle syndrome? |
|
Definition
large group of disorders associated with weakness of the proximal muscles of the arms and legs.
involves dystrophin-glycoprotein complex.
Both autosomal dominant and recessive forms. |
|
|
Term
| What does deficiency in a part of the dystrophin glycoprotein complex cause? |
|
Definition
| results in membrane tears from weakening of the sarcolemma with resultant calcium leak and subsequent muscle necrosis. |
|
|
Term
| How does fascioscapulohumeral dystrophy present? |
|
Definition
Third most common muscular dystrophy.
presents in adulthood, mild facial weakness and weakness of the scapulo-humeral muscles.
autosomal dominat with variable penetrance. |
|
|
Term
| What are the characteristics for EMGs and NCVs for myopathic diseases? |
|
Definition
NCV=sensory nerve conduction is normal. motor neuron may be normal or reduced in amplitude
EMG= motor unit potentials are small in duration and amplitude |
|
|
Term
| How does myotonic dystrophy present? |
|
Definition
| mild to moderate progressive weakness of face neck and limbs. myotonia, frontal balding, temporal wasting, cardiac conduction defects and cataracts. |
|
|
Term
| What is the genetic basis for myotonic dystrophy? |
|
Definition
- most common inherited muscle disease in adults
CTG repeat in chromosome 19. |
|
|
Term
| What is oculopharyngeal dystrophy? |
|
Definition
autosomal dominant disease with ptosis and dysphagia.
trinucleotide repeat disorder as well |
|
|
Term
| What is MERRF? What are the ragged red fibers? |
|
Definition
Myoclonic epilepsies and ragged red fibers=myoclonus, seizures, ataxia, hearing loss, optic atrophy and weakness
RRF= accumulated diseased mitochondria in the subsarcolemma region of the cell |
|
|
Term
| What group of myopathies can cause periodic paralyses? |
|
Definition
mutations in muscle membrane ion channels.
hypokalemia=Ca channels |
|
|
Term
| What are the acquired diseases of muscle? |
|
Definition
inflammatory myopathies
infections
toxins
NMJ disorders |
|
|
Term
| What are the three types of noninfection based inflammatory myopathies |
|
Definition
polymyositis
dermatomyositis
inclusion body myositis |
|
|
Term
| What are the treatments for polymyositis and dermatomyositis? |
|
Definition
| Steriods and other immune mediating treatments e.g. plasma exchange and IVIG |
|
|
Term
| How does polymyositis present? |
|
Definition
-mostly with adults
-presents as weeks to months of proximal weakness and myalgias |
|
|
Term
| What causes polymyositis? |
|
Definition
| It results from HLA restricted antigen specific immune response against muscle fibers. |
|
|
Term
| what lab test is consistent with inflammatory myopathies? |
|
Definition
|
|
Term
| What would muscle biopsy of polymyositis show? |
|
Definition
| invasion of non necrotic fibers by CD8 T cells and macrophages |
|
|
Term
| How does dermatomyositis present? |
|
Definition
-all ages
-progressive weakness over weeks to a few months that affects the neck flexors, shoulder and pelvic girdle.
many other associated signs e.g. =rash, periungal erythema, gottrens sign, subQ calcifications |
|
|
Term
| What is characteristic of muscle biopsies for inclusion body myositis? |
|
Definition
| -invasion by cytotoxic T cells and deposition of amyloid. |
|
|
Term
| What is the presentation of inclusion body myositis? |
|
Definition
proximal weakness of quads and finger flexors.
serum ck is normal or only slightly elevated |
|
|
Term
| What kind of infections can cause inflammatory myopathies? |
|
Definition
1. viruses: flu, coxsackie, mumps, EBV
2. HIV= high serum ck and proximal weakness
3. bacterial infections: staph aureus
4. protozoans, helminths |
|
|
Term
| What laboratory tests can be useful for diagnosing myasthenia gravis? |
|
Definition
1. 70-80% have detectable antiacetylchoine receptor antibodies
2. 5-10% have MuSK antibodies
3. repetitive nerve stimulation decrement
4. chest CT/MRI to evaluate thymus
5. tensilon (edrophonium) |
|
|
Term
| How does Eaton-Lambert syndrome present? |
|
Definition
| proximal weakness, with dry eyes and mouth, constipation and impotence |
|
|
Term
| What is the cause of Eaton-Lambert syndrome? |
|
Definition
autoantibodies against presynaptic Ca gated channels. This decreases the influx of Ca and thus reduced the amount of Ach released.
Many are related to small cell cancer of the lungs |
|
|
Term
| What is diagnostic for lambert-eaton vs myastehnia gravis? |
|
Definition
| lambert-eaton EMGs show faciliation with EMG. i.e. repetitive nerve stimulation at high rates release more acetylcholine and reduce the effects of the disease. |
|
|
Term
| What are the differential diagnoses related to botulism toxin poisoning? |
|
Definition
| guillian barre, MG, organophosphate poisoning |
|
|
Term
What is the molecular genetic defect that results in Duchennes muscular dystrophy?
How is it different from Becker muscular dystrophy? |
|
Definition
Mutations that result in the loss of dystrophin result in instability between the cytoskeleton of the muscle and the membrane. This leads to calcium leakage and muscle destruction.
Becker's are mutations that lead to smaller amounts or smaller dystrophin being produced. This leads to milder symptoms.
It is a X-linked recessive disease. |
|
|
Term
| What does limb girdle muscular dystrophy result from? |
|
Definition
| Disruption of other members of the dystrophin complex. |
|
|
Term
| What does congenital muscular dystrophy result from? |
|
Definition
| mutations in laminin-2 which a is a link to the basement membrane of muscle. |
|
|
Term
| What is the proportion of ALS that is genetic? |
|
Definition
|
|
Term
| What are the different genes associated with ALS? |
|
Definition
SOD1=superoxide dismutase=converts radical O2 to O2 and H20. In ALS SOD1 acquires a toxic property which affects motor neurons.
TAR-DNA binding protein+FUS/TLS=genes that are associated with RNA binding proteins important for correct splicing of certain genes. |
|
|
Term
| What types of muscles and neurons does the disease SMA affect? |
|
Definition
| lower motor neurons in the anterior horn of the spinal cord. these cause proximal spinal muscle atrophy. |
|
|
Term
| What genetic defects cause SMA? Why are different forms of SMA observed? |
|
Definition
In SMA, the gene SMN1 is lost or mutated. This gene produces the SMN protein.
In the human genome, there is a near identical copy of the SMN1 gene called SMN2 gene.
SMN2 is not equivalent to SMN1 as it splices to products mostly lacking exon 7, although low levels of normal SMN protein are produced.
The SMN1 gene can either mutate into the SMN2 gene or be lost.
Different copy numbers of SMN2 produce the various phenotypes i.e. more SMN2 copies=milder symptoms. |
|
|
Term
| What is the molecular genetics behind CMT1A? (a type of HMSN) |
|
Definition
mutation in the PMP22 gene which enocides peripheral myelin protein. The most common mutation is a duplication mutation. Same gene that affect CMT3A
On the other hand deletion of the PMP22 gene results in a distinct peripheral neuropathy. |
|
|
Term
| what is the difference in NCV between CMT 1 and CMT 2? What genes are affected? |
|
Definition
| CMT2 is an axonal polyneuropathy. NCV are normal and there is no obvious demyelination. The genes affected are RAB7 and GARS |
|
|
Term
| What kind of disorder is Hungtinton's? What gene is responsible for causing it? |
|
Definition
Huntington's is a trinucleotide repeat disorder. Within the IT15 gene, there is an expansion of a CAG codon which leads to an extensive polyglutamate stretch in the protein. This results in the deposition of protein in nuclear inclusions with certain areas of the brain such as the cerebral cortex, putamen and caudate nucleus.
this results in cognitive disorganization and muscle discoordination that get progressively worse with time. |
|
|
Term
| What type of genetic defect causes myotonic dystrophy? Why are symptom onset earlier for children than for parents? |
|
Definition
CTG expansion in 3'UTR that causes the unnecessary removal of protein from where it should be.
Anticipation=mean symptom onset is earlier because of the tendency of CTG repeats to enlarge when transmitted from one generation to the next. |
|
|
Term
| What are the clinical signs and symptoms of myotonic dystrophy? |
|
Definition
1. fail to release gripped objects quickly
2. cataracts
3. ptosis
4. muscle weakness |
|
|
Term
| Describe the inheritance pattern of fragile X syndrome |
|
Definition
Fragile X syndrome is the result of CCG repeats in the 5' promotoer region of the FMR gene which can cause a shut down of FMR expression.
It is only inherited from the mother because expansion of the number of repeats only occurs in females. |
|
|
Term
| What are the clinical symptoms of spinocerebellar ataxia? What is the genetic defect that causes it? |
|
Definition
Affects the purkinje cell layer resulting in gait ataxia, dysarthria.
caused by polyglutamate expansion in gene coding for androgen receptor. |
|
|
Term
| What are some genetic risk factors for Alzheimer's? |
|
Definition
PS1 and PS2 mutations(secretase enzymes that cleave APP protein)
ApoE4 mutations
APP mutations |
|
|
Term
| What are the cytopathologic changes observed with alzheimer's disease? |
|
Definition
Affected neurons accumulate tau and ubiquitin within neurofibrillary tangles.
In addition to the neurofibrillary tangles, AD patients show numerous senile plaques which are composed of dystrophic neurites. |
|
|
Term
What mutations cause dominant expression of parkinson's?
recessive? |
|
Definition
dominant=LRRK2, UCH1 (alpha synuclein deposition)
Recessive=Parkin, DJ1 and Pink 1. (important for the ubiquitin proteasome pathway (UPP)) |
|
|
Term
| What are ways to decrease the systemic effects of a topical medication in the eye? |
|
Definition
1. use an ointment
2. punctal occlusion
3. lid closure (reduces by up to 60% because tears are not swept into duct) |
|
|
Term
| What are the routes of opthalmic drug administration? |
|
Definition
-topical
-subconjunctival
-sub-tenon's capsule
-systemic
-intraocular |
|
|
Term
| What is the difference between subconjunctival injection and subtenon's injection? |
|
Definition
subconjunctival=reservoir of mediaciton that leaches through the puncture in the conjunctiva and enters eye through topical route
-subtenon=direct penetration of the sclera |
|
|
Term
| How are intraocular injections given? |
|
Definition
| through the pars plana, this is the obly way to obtain consistent intraocular levels of drug |
|
|
Term
| Why is long term use of topical opthalmic anesthetics contraindicated? |
|
Definition
| It is toxic to the cornea |
|
|
Term
| What are the topical open angle glaucoma drugs? |
|
Definition
-beta blockers
-alpha 2 agonists
-prostaglandins
-carbonic anhydrase inhibitors |
|
|
Term
| What are the side effects of beta blocker use? |
|
Definition
-exacerbation of asthma
-bradycardia
-heart block
-impotence
-depression |
|
|
Term
| which glaucoma drug is contraindicated in children and why? |
|
Definition
| -alpha-2 agonists=CNS depression |
|
|
Term
| How do prostaglandins reduce glaucoma symptoms and what are some side effects? |
|
Definition
-increase uveoscleral outflow
SE=change of eye color, increased length of eye lashes, ocular inflammation |
|
|
Term
| what carbonic anhydrase oral use? |
|
Definition
-decreased appetite
-malaise
-hypokalemia
-acidosis
-kidney stones
-skin rash
-rare aplastic anemia** |
|
|
Term
| What is the action of cholinergics on the eye? |
|
Definition
cholinergics=parasympathetic
This results in miosis and cycloplegia=increase aqueous outflow through trabecular meshwork |
|
|
Term
| What are so examples of direct acting cholinergics? |
|
Definition
| acetylcholine, carbachol and pilocarpine |
|
|
Term
| what are some examples of indirect acting cholinergics? |
|
Definition
| physostigmine, demecarium, echothiophate, isoflurate |
|
|
Term
| What are some uses of cholinergics? |
|
Definition
-OAG (infrequently)
-acute angle closure glaucoma
-miosis
-esotropia
-myesthenia gravis |
|
|
Term
| What are the antibiotics of choice for bacterial keratitis of the eyes? |
|
Definition
| fluoroquinolones i.e. ciprofloxacin, ofloxacin, levofloxacin, norfloxacin |
|
|
Term
| What agents can be used to osmotically lower vitreous pressure? |
|
Definition
|
|
Term
| how do dilatory agents work? |
|
Definition
Two ways: adrenergic agonist direct acting: phenylephrine+epineprhine
anticholinergics (dilation and cycloplegia) iris sphincter paralysis so dilation is unopposed. e.g. tropicamide, scopolamine and atropine |
|
|
Term
| What are the opthalmic side effects of steroid use? |
|
Definition
increased IOP in 30% of the population after about a month of steroid use.
cataract formation |
|
|
Term
| what are the side effects of amiodarone use? |
|
Definition
|
|
Term
| What is hydroxychloroquine used for? What side effects can it have? |
|
Definition
It is an antimalarial.
can cause macular degneration |
|
|
Term
| What are the side effects of topiramate? what is it used for? |
|
Definition
topiramate is used to treat certain types of seizure i.e. lennox-gastaut
can cause open agnle glaucoma |
|
|
Term
| what are some of the side effects of topical steroids? |
|
Definition
-increased IOP
-cataracts
-susceptibilty to infection
-activation/exacerbation of herpes
-corneal perforation |
|
|
Term
| How can partial nerve injury results in the nerve fiber becoming hyper excitable? |
|
Definition
-production of repetitive volleys of action potentials to a single stimulus
-may allow spontaneous generation of nerve impulses causing positive symptoms of nerve injury such as burning and tingling |
|
|
Term
| How does complete nerve injury occur? |
|
Definition
-axon transection
-loss of myelin over a large enough segment. |
|
|
Term
| what is wallerian degeneration? |
|
Definition
| -pathologic process of structural disintegration and chemical degradation when an axon is transected |
|
|
Term
| what is central chromatolysis? |
|
Definition
| -when there is damage to a neuron, the RER disaggregates, the neuronal body balloons, the nucleus is displaced peripherally and reparative protein synthesis occurs. |
|
|
Term
| What type of sensory modalities do small nerve fibers carry? What symptoms do complete and partial nerve injury to small diameter nerve fibers result in? |
|
Definition
pain and temperature
complete=numbness
partial=pain, wamth, cold, burning, dysesthesias |
|
|
Term
| What sensory modalities do large diameter sensory fibers carry? what do complete and partial nerve injuries result in? |
|
Definition
mechanoreceptors, muscle spindle (proprioception)
complete=sensory ataxia, decreased vibtration, position sense and tendon reflexes
partial=tingling and buzzing |
|
|
Term
What does complete injury to a motor nerve result in?
partial? |
|
Definition
complete=weakness, atrophy, decreased tendon reflexes
partial=cramps, fasciculation |
|
|
Term
| what is the difference between fasciculation and fibrillations |
|
Definition
fibrillations=complete motor neuron injury; membrane potential oscillates rhythmatically above and below threshold and causes spontaneous recurring contraction
fasciculations=twitch when single discharge in a hyperexitable axon terminal travels back up to other branches of the motor unit |
|
|
Term
|
Definition
| When a neuron is hyperexitable it can lead to sponstanteous rapid repetitive discharge and produce a cramp |
|
|
Term
| What injuries can nerve overactivity result in? |
|
Definition
-excessive sweating
-increased blood flow |
|
|
Term
| What symptoms result from the loss of autonomic function? |
|
Definition
-abnormal fall in bp on rising (use tilt table to test)
-impaired sweating and ability to initiate bladder or bowel evacuation
-impotence |
|
|
Term
What is aphasia?
dysarthria?
dysphonia |
|
Definition
-impairment of the production and/or comprehension of written or spoken language.
dysarthria=defect in articulation due to difficulty with motor function
dysphonia=loss of ability to speak because of larynx disorder |
|
|
Term
|
Definition
-loss of speech fluency due to lesion in dominant hemispheric inferior frontal gyrus.
associated with weakness of right arm and right face |
|
|
Term
| What is wernicke's aphasia? |
|
Definition
| -though speech is fluent, it is unintelligble because of frequent error in word choice. trouble comphrehending others. |
|
|
Term
| what is conduction aphasia? |
|
Definition
-damage to the arcuate fasciculus which connects the two major speech areas.
comphrehension and fluency is conserved but repitition is affected |
|
|
Term
|
Definition
| when the entire perislyvian area is lesioned. features of both Broca and wernicke's aphasia |
|
|
Term
| What are some symptoms of frontal lobe lesions? |
|
Definition
-hemiparesis
-personality changes =apathy, euphoria, jocularity, irritability, social inappropriateness
-urinary incontinence |
|
|
Term
| what are tests for frontal lobe lesions? |
|
Definition
-alternating sequences
-fist palm side |
|
|
Term
| What are the symptoms of temporal lobe lesion? |
|
Definition
-bilateral lesions=memory loss
-dominant side=decreased verbal learning and wernicke's aphasia
-nondominant=decreased visual learnings
-visual field defects |
|
|
Term
| What are the symptoms of parietal lobe lesions that are independent of dominance? |
|
Definition
sensory intergration disorders:
1. astereogenesis
2. agraphesthesia
3. decreased 2 point discrimination
4. neglect and anosognosia
5. extinction (stimulus is percieved when applied alone to side contralateral to lesion by not when stimuli applied bilaterally). |
|
|
Term
| What are the symptoms of dominant parietal lobe syndrome? |
|
Definition
| Gerstmann's syndrome: impaired calculation, left-right confusion agnosia, finger agnosia, dysgraphia, apraxia(can't perform simple commands). |
|
|
Term
| What are the symptoms of nondominant parietal lobe syndrome? |
|
Definition
1. neglect of opposite side of body
2. impaired constructional ability |
|
|
Term
|
Definition
| incoordination or clumsiness of movement not caused by weakness or sensory loss |
|
|
Term
| What does the Romberg test distinguish between? |
|
Definition
cerebeller and sensory ataxias. If the patient is unstable with their eyes closed then it is likely to be a sensory ataxia
The patient will probably already be unsteady with eyes open with truncal cerebellar ataxia or vestibular dysfunction |
|
|
Term
| How do cerebellar ataxias manifest? |
|
Definition
irregularities in rate, rhythmn, amplitude or force of voluntary movements
due to lesion in cerebellum itself or in cerebellar peduncles, pons or red nucleus
1.dysemetria
2. intention tremor
3. hypotonia and rebound phenomenon
4. oculomotor abnormalaties
5. dysarthria |
|
|
Term
| How do you differentiate upper motor neuron and lower motor neuron facial palsies? |
|
Definition
UMN: spares the forehead due to bilateral innervation
LMN: entire side of the face including the forehead is weak so lesion is at the level of the pons or lower. |
|
|
Term
| How do you distinguish upper motor and lower motor neuron signs? |
|
Definition
upper motor neuron- increased tone spasticity, hyperreflexia, extensor plantar response(babinski sign)
lower motor neuron=decreased tone, hyporeflexia, flexor plantar response, muscle atrophy and fasciculations |
|
|
Term
| What nerve roots correspond to the ankle, patellar, biceps and triceps reflexes? |
|
Definition
ankle=s1, s2
patellar= L3, L4
biceps=c5, c6
triceps=c7, c8 |
|
|
Term
|
Definition
| A condition that affects many nerves at the same time. Begins in the legs and later affects the arms in a symmetric stocking and glove fashion. |
|
|
Term
|
Definition
| pathology involving a single nerve. However in clinical practice there are usually multiple single nerves involved. However functional loss can be traced to single nerves. |
|
|
Term
| What are the four pathological classifications of peripheral nerve disorders? |
|
Definition
| neuronopathies, myelinopathies, distal axonopathies and vasculopathies |
|
|
Term
| if vasculitis is the cause of peripheral nerve disease, how is the final diagnosis made? |
|
Definition
Final diagnosis is based on tissue diagnosis. A segment of cutaneous nerve is removed from the sural or superficial peroneal.
nerve fibers will appear ischemic (Wallerian degeneration) and are non selective i.e. either sensory or motor |
|
|
Term
| What is the most common vasculitis? |
|
Definition
|
|
Term
| What disease affects the nerves of the lower brainstem as well as the cell bodies innervating limb musculature? |
|
Definition
Amyotrophic lateral scerlosis i.e. lou gehrig's disease. It is progressive and fatal within 3-5 years.
Weakness and atrophy in limbs, pharyngeal muscles and tongue |
|
|
Term
| Is ALS upper or lower motor neuron? |
|
Definition
| It is both and will show signs of reflex loss as well as hyperreflexia. |
|
|
Term
| What is the predominant clinical feature of dorsal root ganglion neuropathies? |
|
Definition
Marked sensory loss, patients can not find their limbs in space. (kinesthetic loss).
There are also varying degress of other modality loss i.e. pinpricl, temperature and vibration. |
|
|
Term
| In dorsal root ganglion neuropathies what part of the neuron degenerates? What will an EMG and nerve conduction show? |
|
Definition
the projections to the posterior columns degenerate.
EMGs will be largely normal because the muscle is not deenervated. Nerve conduction studies show little or no change in the velocity of the nerve. However if all nerves degenerate there is no evocable response and the nerve conductance can no be measured. |
|
|
Term
| What are some causes of dorsal root ganglion cell bodies. |
|
Definition
| Cancer, Sjorgen's syndrome, vitamin B6 toxicity, cisplatin and HIV(rare) |
|
|
Term
| What disorder is associated with children in the first decade causing generalized weakness and skeletal abnormalities? |
|
Definition
| Charcot-Marie-Tooth type 3A and 3B. abnormalities include scoliosis, pes cavus and hammer toes |
|
|
Term
| How does CMT1A and CMT1B present? |
|
Definition
| weakness and sensory loss of the hands and feet (stocking and glove). Comes in the first or second decade of life. The patients almost always have pes cavus and hammer toes. |
|
|
Term
| What is the major laboratory abnormality associated with charcot marie tooth. |
|
Definition
| slow nerve conduction velocities due to the loss of myelin. (CMT is an inherited demyelination disease that is polyneuropathic). Myelin loss is uniformly spread throughout the nerves |
|
|
Term
| What type of infection is commonly associated with guillain barre syndrome? |
|
Definition
|
|
Term
| How is GBS treated? how is it not treated? |
|
Definition
| immunosupression via IVIG or plasma exchange. don't use steroids |
|
|
Term
|
Definition
Preceded 1-2 weeks prior by a cold or flu like illness.
Initially numbness of the extremities followed by weakness in limbs. facial muscles can also be affected. |
|
|
Term
| What key lab features distinguish GBS and CIDP? |
|
Definition
1. CSF=elevated protein(from myelin) and normal cell count=albuminocytologic dissociation
2. NCV are slow but since process is not uniform and random hit plus miss, some nerves are slower than others. |
|
|
Term
| What is the difference between GBS and CIDP( chronic inflammatory demyelinating polyneuropathy) |
|
Definition
|
|
Term
| How do distal axonopathies present? |
|
Definition
axonal neuropathies are length dependent and are often caused by metabolic abnormalities that affect axonal transport.
Therefore longer axons are affected first.
This leads to stocking and glove distribution starting in feet and working up. when reach knees, the hands start to be affected. |
|
|
Term
| What are some etiologies for distal axonopathies? |
|
Definition
1. diabetes mellitus
2. uremia
3. amyloidosis
4. ETOH
5. thiamine deficiency
6. phenytoin toxicity |
|
|
Term
| What are the causes of multiple mononeuropathy? |
|
Definition
1. diabetes
2. vasculitis
3. sarcoidosis
4. leprosy
5. hypothyroidism
6. hereditary neuropathy with liability to pressure palsies |
|
|
Term
| What can an EMG tell you about the class of disease? |
|
Definition
Distinguish between neuronopathies and myopathies
neuropathies=increase in amplitude (because of reinnervation) and increase in duration of action potential
myopathies=decrease in action potential duration and decrease in the amplitude |
|
|
Term
| What does slowing of NCV indicate? |
|
Definition
|
|
Term
| Each sacromere is divided into different areas: the Z band, the I band, the A band and the H band. What make is the composition of each of these bands. |
|
Definition
Z band= Z discs which mark the boundary of each sarcomere
I band= thin fibers of actin
A band=anisotopic band made up of thick myosin filaments.
H band= area of A band that only has myosin fibers. |
|
|
Term
| Myosin is a complex protein that functions as an ATPase that converts ATP to mechanical energy. What ions activate and inhibit its function? |
|
Definition
| myosin is activated by Ca2+ and inhibited by Mg2+ |
|
|
Term
| What is the function of tropomysin and troponin? |
|
Definition
tropomysin is a long filamentous protein that lies in the groove formed by the actin helix.
troponin is a small protein bonded to the tropomysin filament at regular intervals. |
|
|
Term
| What is the function of the sarcoplasmic reticulum? |
|
Definition
| It is an intracellular membranous system that surrounds myofibrils in a parrallel fashion. It functions as a storage system for Ca2+ which is released during an action potential. |
|
|
Term
| How does Ca2+ allow for muscle contraction? |
|
Definition
| It causes the release of tropomysin from the actin helix grooves by binding to troponin. This allows myosin to bind. |
|
|
Term
| What four states is the head of myosin filaments in? |
|
Definition
1)The actin-myosin bridge rapidly dissociates due to ATP binding to myosin
2)The free myosin moves into position to attach to actin, and ATP is hydrolyzed
3)The free myosin bridge rebinds to the actin filament along with its hydrolysis products
4)The cross-bridge generates force, and actin displaces the ADP and Pi from the myosin cross-bridge. |
|
|
Term
| What type of receptor is the acetylcholine receptor on the postsynaptic side of the NMJ? |
|
Definition
| It is a nicotinic receptor. When two molecules of Ach bind these receptors change confirmation to allow Na+ into the muscle cell. |
|
|
Term
| How does the venom alpha-bungarotoxin cause paralysis? |
|
Definition
| alpha-bungarotoxin can compete with acetylcholine to bind to nicotinic acetylcholine receptors and cause neuromuscular blockade. |
|
|
Term
| How is the endplate potential generated? |
|
Definition
Na+ influx following acetylcholine binding results in a depolarization that is similar to the EPSP in a neuron.
resting potential of muscles are -90mV. |
|
|
Term
| What is the action of curare? |
|
Definition
| curare blocks the binding of Ach to its receptor and prevents the epp from reaching threshold to trigger a muscle action potential |
|
|
Term
| What system delivers the muscle action potential deep into the muscle. |
|
Definition
|
|
Term
| How is Ca2+ released in the muscles? |
|
Definition
| When the MAP depolarizes the T-tubules, DHP receptors are activeted which allow extracellular calcium into the muscle cell. These receptors are associated with Ca2+ release channels (ryanodine receptors) in the SR. |
|
|
Term
| What are the two types of muscle fiber? |
|
Definition
type 1= slow fibers used to maintain posture, slow twitch speed and high resistance to fatigue. rely on oxidative metabolism. darker because more capillaries.
type 2= low resistance to fatigue and a fast twitch speed. (lighter because fewer capillaries)
2A-intermediate=fast oxidative glycolytic
2B-fast fatigable=fast glycolytic |
|
|
Term
|
Definition
Dystrophin is a protein located on the inner surface of the muscle membrane. The amino terminus is linked to cytoskeletal actin and the carboxy terminal to the sarcolemma.
mutations in dystrophin cause muscular dystrophies such as Duchenne muscular dystrophy. |
|
|
Term
| What are the features of normal muscle histology? |
|
Definition
1. 40-80u size
2. polygonal size
3. checkerboard mosaic of type 1 and 2 fibers
4. ratio of type 1 to 2 is 1:2
5. less that 3% internal nuclei
6. small amount of endomysial connective tissue. |
|
|
Term
| What are the histological changes associated with myopathy? how would you distinguish acute versus chronic? |
|
Definition
1. rounding of muscle fibers
2. hypertrophy of fibers
3. increased numbers of internal nuclei.
acute=necrosis and phagocytosis of muscle fibers
chronic=increased endomysial connective tissue. |
|
|
Term
| What are the histological changes associated with neuropathy? |
|
Definition
recent denervation
1. small angular fibers
2. pyknotic nuclear clumps
Chronic denervation
1. fiber type grouping: loss of normal mosaic checkerboard appearance. |
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Term
| Each sacromere is divided into different areas: the Z band, the I band, the A band and the H band. What make is the composition of each of these bands. |
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Definition
Z band= Z discs which mark the boundary of each sarcomere
I band= thin fibers of actin
A band=anisotopic band made up of thick myosin filaments.
H band= area of A band that only has myosin fibers. |
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Term
| Myosin is a complex protein that functions as an ATPase that converts ATP to mechanical energy. What ions activate and inhibit its function? |
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Definition
| myosin is activated by Ca2+ and inhibited by Mg2+ |
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Term
| What is the function of tropomysin and troponin? |
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Definition
tropomysin is a long filamentous protein that lies in the groove formed by the actin helix.
troponin is a small protein bonded to the tropomysin filament at regular intervals. |
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Term
| What is the function of the sarcoplasmic reticulum? |
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Definition
| It is an intracellular membranous system that surrounds myofibrils in a parrallel fashion. It functions as a storage system for Ca2+ which is released during an action potential. |
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Term
| How does Ca2+ allow for muscle contraction? |
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Definition
| It causes the release of tropomysin from the actin helix grooves by binding to troponin. This allows myosin to bind. |
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Term
| What four states is the head of myosin filaments in? |
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Definition
1)The actin-myosin bridge rapidly dissociates due to ATP binding to myosin
2)The free myosin moves into position to attach to actin, and ATP is hydrolyzed
3)The free myosin bridge rebinds to the actin filament along with its hydrolysis products
4)The cross-bridge generates force, and actin displaces the ADP and Pi from the myosin cross-bridge. |
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Term
| What type of receptor is the acetylcholine receptor on the postsynaptic side of the NMJ? |
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Definition
| It is a nicotinic receptor. When two molecules of Ach bind these receptors change confirmation to allow Na+ into the muscle cell. |
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Term
| How does the venom alpha-bungarotoxin cause paralysis? |
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Definition
| alpha-bungarotoxin can compete with acetylcholine to bind to nicotinic acetylcholine receptors and cause neuromuscular blockade. |
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Term
| How is the endplate potential generated? |
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Definition
Na+ influx following acetylcholine binding results in a depolarization that is similar to the EPSP in a neuron.
resting potential of muscles are -90mV. |
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Term
| What is the action of curare? |
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Definition
| curare blocks the binding of Ach to its receptor and prevents the epp from reaching threshold to trigger a muscle action potential |
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Term
| What system delivers the muscle action potential deep into the muscle. |
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Definition
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Term
| How is Ca2+ released in the muscles? |
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Definition
| When the MAP depolarizes the T-tubules, DHP receptors are activeted which allow extracellular calcium into the muscle cell. These receptors are associated with Ca2+ release channels (ryanodine receptors) in the SR. |
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Term
| What are the two types of muscle fiber? |
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Definition
type 1= slow fibers used to maintain posture, slow twitch speed and high resistance to fatigue. rely on oxidative metabolism. darker because more capillaries.
type 2= low resistance to fatigue and a fast twitch speed. (lighter because fewer capillaries)
2A-intermediate=fast oxidative glycolytic
2B-fast fatigable=fast glycolytic |
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Term
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Definition
Dystrophin is a protein located on the inner surface of the muscle membrane. The amino terminus is linked to cytoskeletal actin and the carboxy terminal to the sarcolemma.
mutations in dystrophin cause muscular dystrophies such as Duchenne muscular dystrophy. |
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Term
| What are the features of normal muscle histology? |
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Definition
1. 40-80u size
2. polygonal size
3. checkerboard mosaic of type 1 and 2 fibers
4. ratio of type 1 to 2 is 1:2
5. less that 3% internal nuclei
6. small amount of endomysial connective tissue. |
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Term
| What are the histological changes associated with myopathy? how would you distinguish acute versus chronic? |
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Definition
1. rounding of muscle fibers
2. hypertrophy of fibers
3. increased numbers of internal nuclei.
acute=necrosis and phagocytosis of muscle fibers
chronic=increased endomysial connective tissue. |
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Term
| What are the histological changes associated with neuropathy? |
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Definition
recent denervation
1. small angular fibers
2. pyknotic nuclear clumps
Chronic denervation
1. fiber type grouping: loss of normal mosaic checkerboard appearance. |
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Term
| What is the difference between cell and flare? |
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Definition
Cell=describes the presence of inflammatory cells in the aqueous or vitreous humor
flare= turbid or vitreous humor as a result of proteins leaking out of the vasculature |
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Term
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Definition
| a layer of aqueous inflammatory cells in teh inferior aspect of the anterior chamber angle |
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Term
| What are keratic precipitates? |
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Definition
| deposits of inflammatory cells on the endothelial surface of the cornea |
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Term
| What is the difference between anterior and posterior synechiae? |
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Definition
anterior= iris stuck to cornea
posterior=iris stuck to lens |
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Term
| How can you treat synechiae? |
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Definition
| topical mydriatic/cycloplegics i.e. topical atropine to make the iris contract away from the adhesion. |
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Term
| Uveitis is associated with which HLAs? |
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Definition
HLA-A29 and HLA-B27.
HLA-B27=anterior uveitis and also associated with ankylosing spondylitis |
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Term
| What is the difference between episcleritis and scleritis? |
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Definition
episcleritis=sectorial, non vision threatening and painless
scleritis=deep inflammation of the sclera, painful and tender. |
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Term
| What is the presentation of anterior uveitis? |
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Definition
-inflammation of the cornea, iris, ciliary body.
-photophobia
-red eye with injection of vessels at the corneal limbus
-inflammatory cells in the aqueous humor |
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Term
| What are the etiologies of anterior uveitis? |
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Definition
-mostly idiopathic
-HLA-B27
-JRA
-HSV |
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Term
| What is the presentation of intermediate uveitis? |
|
Definition
-inflammatory cells in the anterior vitreous
-floaters
-snowbank on inferior pars plana |
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Term
| What is the presentation of the posterior uveitis? |
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Definition
| -decreased vision with or without floaters. |
|
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Term
| what are the etiologies of posterior uveitis? |
|
Definition
usually infectious
-toxo
-sarcoidosis
-histo
idiopathic mostly |
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Term
| What are some conditions that may present as uveitis? |
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Definition
1. non-hodgkin's lymphoma of CNS
2. leukemia
3. intraocular foreign body |
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Term
| What is the treatment for uveitis? |
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Definition
| use steroids to reduce inflammatory reaction. However be careful, if infectious etiology, immune suppression can result in a flare up of infection. Use with broad spectrum antibiotics as well. |
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Term
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Definition
| Drusen are tiny yellow or white accumulations of extracellular material that build up in the eye |
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Term
| How do you distinguish between Drusen and hard exudate? |
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Definition
| Both are examples of small white pathology. Drusen are reflective to light while hard exduate are not. Hard exudate are also often in a characteristic circular or star pattern(around the macula) and can be associated with hemorrhages. |
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Term
| What type of white pathology will conceal retinal vessels? |
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Definition
| proliferative diabetic retinopathy. looks like white scar tissue |
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Term
| When white pathology is below choroidal vessels, what part of the eye is being viewed? |
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Definition
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Term
| When white pathology is on the same level of retinal arterioles, what pathology does this indicate? |
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Definition
| An occluded arteriole, with the area of white pathology being associated with the area of retina supplied by that vessel. |
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Term
| What condition is associated with scleral white pathology? |
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Definition
| chorioretinitis and eventual scarring. Initially only white pathology but eventually it will be surrounded by a black donut of scar tissue. |
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Term
| Rounded white pathology indicates? |
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Definition
| soft exudate=sign of ischemia |
|
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Term
| What does striated white pathology indicate? |
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Definition
|
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Term
| What two layers is melanin found in? |
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Definition
| retinal pigment epithelium and choroid |
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Term
| There are two types of disc black pathology. How do you distinguish the two? |
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Definition
retinal melanoma vs choroidal nevus.
melanomas are elevated, choroidal nevus' are flat (but may become melanomas) |
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Term
| What does angular black pathology indicate? |
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Definition
retinitis pigmentosa (black bone spiculed pigmentation)
also can be indicative of syphillis infections. |
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Term
| black doughnut shaped black pathology? |
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Definition
| chorioretinal scar (old chorioretinitis) |
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Term
| What hemorrhages are considered "small"? |
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Definition
| If they are less than 1/3 to 1/2 the size of the optic disx |
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Term
| What three groups of vessels can bleeding occur from? |
|
Definition
1. disc
2. retinal
3. choroidal |
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Term
| How can you distinguish preretinal from subretinal hemorrhages? |
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Definition
pretretinal hemorrhages will conceal retinal vessels and also have a flat top.
subretinal hemorrhages will be behind vessels. |
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Term
| What do hemorrhages in the nerve fiber layer look like? |
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Definition
| linear and small. can come from either the disc or the retinal vessels. |
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Term
| If the hemorrhage comes from the disc, this indicates what kind of etiology? choroid? |
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Definition
neurologic.
choroid=degenerative or inflammatory |
|
|
Term
| what does a small rounded hemorrhage indicate? |
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Definition
| a deep intraretinal hemorrhage |
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