Term
|
Definition
|
|
Term
|
Definition
| 2 weeks to several months |
|
|
Term
|
Definition
fever, anorexia
self-inflicted injuries
can mimic any of the CNS diseases of the horse
bizarre frequently changing neurological signs
Encephalitic Form-depression, aggression, dysphagia, facial paresis/paralysis, altered vocalization
progress quickly to recumbency, coma, convulsions, death
Spinal form-ascending flaccid paralysis
rapidly progressing to encephalitic form and recumbency |
|
|
Term
|
Definition
| all horses should be vaccinated yearly |
|
|
Term
| Viral Encephalomyelitis Diseases |
|
Definition
Eastern Equine Encephalomyelitis
Western Equine Encephalomyelitis
Venezualan Equine Encephalomyelitis
West Nile Virus Encephalomyelitis |
|
|
Term
| Viral Encephalomyelitis Diseases Signs |
|
Definition
fever
anorexia
diarrhea (VEE)
depression, dementia, aggression, somnolence, facial twitching (WNV), blindness, recumbency, coma, death |
|
|
Term
| Viral Encephalomyelitis Diseases Clinical Pathology |
|
Definition
neutropenia, lymphopenia
CSF has increased neutrophils, lymphocytes, and total protein |
|
|
Term
| Viral Encephalomyelitis Diseases Treatment |
|
Definition
control seizures, maintain hydration, antibiotics for secondary infections
treat ulcers, roll/sling if recumbent
corticosteroids may improve WNV signs |
|
|
Term
| Viral Encephalomyelitis Diseases Prognosis |
|
Definition
guaraded
mortality is high
takes weeks to become normal or may have residual neurologic deficits |
|
|
Term
| Viral Encephalomyelitis Diseases Prevention |
|
Definition
| vaccinate annually or twice annually if mosquito season is long |
|
|
Term
| Cerebral/Spinal Abscesses Pathogenesis |
|
Definition
bastard strangles
Streptococcus equi equi
unilateral cortical signs develop
spinal abscesses are rare in horses but more common in cattle
results in signs of focal compressive lesion |
|
|
Term
| Cerebral/Spinal Abscesses History |
|
Definition
weanlings, yearlings with previous exposure to Strep. equi
neonatal sepsis
onset of signs may be acute or insidiously slow |
|
|
Term
| Cerebral/Spinal Abscesses Signs |
|
Definition
normal physical exam, may be febrile
depression, head pressing, sudden unprovoked excitement/aggression
circling toward the lesion without a head tilt
may be cortically blind
normal direct and consensual PLRs but contralaterally blinds |
|
|
Term
| Cerebral/Spinal Abscesses Clinical Pathology |
|
Definition
leukocytosis
neutrophilia
increased fibrinogen
increased serum globulins due to chronicity
increased CSF pressure
CSF contains increased nucleated cell count, increased neutrophils, increased RBC, increased protein |
|
|
Term
| Cerebral/Spinal Abscesses Diagnosis |
|
Definition
radiographs will be normal
can do CT and nuclear imaging |
|
|
Term
| Cerebral/Spinal Abscesses Treatment |
|
Definition
Penecillin for 4-6 weeks
3rd generation cephalosporin (cefotaxmine, ceftiofure)
control seizures
surgical drainage |
|
|
Term
| Cerebral/Spinal Abscesses Prognosis |
|
Definition
|
|
Term
| Hepatoencephalopathy Pathogenesis |
|
Definition
primary liver disease from plant toxicities
diseased liver can't filter endogenous toxic substances like ammonia
bizarre neurologic signs results |
|
|
Term
| Hepatoencephalopathy History |
|
Definition
chronic anorexia followed by
acute onset of neurologic signs
exposure to toxic plants
chronic weight loss |
|
|
Term
| Hepatoencephalopathy Signs |
|
Definition
icterus, anorexia, photosensitization
chronic weight loss, self induced trauma
depression, somnolence, spontaneous aggressive behavior, cortical blindness, uncontrollable walking, yawning, head pressing |
|
|
Term
| Hepatoencephalopathy Clinical Pathology |
|
Definition
increased liver enzymes, bilirubin, blood ammonia
decreased BUN, glucose
abnormal BSP and bile acids |
|
|
Term
| Hepatoencephalopathy Treatment |
|
Definition
control seizures
5% dextrose IV to maintain blood glucose at 100-160mg/dl during acute crisis
stop exposure to plants
good quality grass hay
small grain meals more frequently
oral vitamins
metronidazole
minimize stress |
|
|
Term
| Hepatoencephalopathy Prognosis |
|
Definition
guarded if first time
poor if fibrosis and recurrence |
|
|
Term
| Equine Leukoencephalomalacia Pathogenesis |
|
Definition
corn infected with Fusarium
Fusarium produces fumonism toxin
often seen in winter immediately after harvest of new batches of corn with infestation
often seen in the Midwest Corn Belt |
|
|
Term
| Equine Leukoencephalomalacia History |
|
Definition
exposure to moldy corn
dry growing season followed by humid period during harvest
signs follow exposure by 2-24 weeks |
|
|
Term
| Equine Leukoencephalomalacia Signs |
|
Definition
normal physical exam
icterus if concurrent liver disease
self-infecting injuries
cerebral dementia, blindness, lack of awareness of surroundings
behavioral changes
profound proprioceptive deficits may be only sign |
|
|
Term
| Equine Leukoencephalomalacia Clinical Pathology |
|
Definition
|
|
Term
| Equine Leukoencephalomalacia Diagnosis |
|
Definition
history, signs, feed analysis
necropsy is definitive diagnose with liquefactive necrosis of cerebral cortical white matter |
|
|
Term
| Equine Leukoencephalomalacia Treatment |
|
Definition
thiamine advocated but no reason for it
no treatment |
|
|
Term
| Equine Leukoencephalomalacia Prognosis |
|
Definition
| fair to grave depending on neurologic signs |
|
|
Term
| Cerebellar Abiotrophy Pathogenesis |
|
Definition
only described in Arabian horses
gradual degeneration of cerebellum after goal born normally
NOT hypoplasia |
|
|
Term
| Cerebellar Abiotrophy History |
|
Definition
Arabian foal born normally
signs begin within 6 months |
|
|
Term
| Cerebellar Abiotrophy Signs |
|
Definition
normal physical exam
self-induced trauma
intention tremors, spastic goose stepping gait
still has strength
no menace (still a baby) but are not blind |
|
|
Term
| Cervical Vertebral Malformation Pathogenesis |
|
Definition
aka Wobbler Disease
suspected genetic predisposition to fast growth
part osteochondrosis/epiphysitis with overnutrition
causes subluxation of vertebrae into spinal canal
may have OCD lesions often at C3-C4 or at multiple sites
focal compression of spinal cord at one or more cervical spaces results in signs of compressive myelopathy
hind limbs are mostly worse with symmetry |
|
|
Term
| Cervical Vertebral Malformation History |
|
Definition
rapidly growing horses 6-24 months old
predisposition in thoroughbreds, quarterhorses, and warmbloods
overnutrition
owners complain the horse is awkward or as stifle lameness |
|
|
Term
| Cervical Vertebral Malformation Signs |
|
Definition
large horse, epiphysitis
may look lame behind
ataxia, paresis, spasticity, dysmetria
hind limbs nearly always worse than front
if forelimbs same as hind, suspect lesion at C6-T2 |
|
|
Term
| Cervical Vertebral Malformation Diagnosis |
|
Definition
CSF is normal
radiographs reveal subluxation at intervertebral space and stenotic canal
myelography reveals thinning of dorsal and ventral dye |
|
|
Term
| Cervical Vertebral Malformation Treatment |
|
Definition
surgery
if very early, remove grain and feed supplements
stall rest |
|
|
Term
| Occipitoatlantoaxial Malformation Pathogenesis |
|
Definition
only in half-Arabian and Arabians
appear normal at birth but develop signs at 6 months
C1 is fused to base of the skull
C2 rostral has no real dens or dorsal process
Not easy to dx radiographically
As they get older there is greater impingment on the spinal cord and look like Wobbler's
Different pathogenesis but same presentation as Wobblers |
|
|
Term
| Occipitoatlantoaxial Malformation Signs |
|
Definition
palpable bony lump at base of skull where C1 should be
Very focal area of muscle atrophy ventral to C1
stiffness at skull-C1-C2 joints
clicking at joint is manipulated
ataxia, paresis, spasticity, dysmetria |
|
|
Term
| Occipitoatlantoaxial Malformation Diagnosis |
|
Definition
myelograph shows compression
radiographs may not show anything |
|
|
Term
| Occipitoatlantoaxial Malformation Treatment |
|
Definition
surgical stabilization
none |
|
|
Term
| Equine Protozoal Encephalomyelitis Pathogenesis |
|
Definition
Sarcocystic neurona in definitive host of opossum
opossum feeds on prey/roadkill (cat) with cysts in their muscle
opossum passes in feces to horses
horse is dead end host |
|
|
Term
| Equine Protozoal Encephalomyelitis History |
|
Definition
onset of signs acute or chronic
signs often asymmetrical |
|
|
Term
| Equine Protozoal Encephalomyelitis Signs |
|
Definition
asymmetrical extracranial signs
intracranial signs not as common
lameness that will not block out, locking stifle
upper airway abnormality, just behaving differently
nfection can occur anywhere
Can have any sort of Cranial nerve sign or in cervical spine
Infection will be focal and will have one sided neurologic signs
In spinal cord lesions
May have focal areas of sweating from dermatomes
Asymmetrical muscle atrophy of just one muscle group |
|
|
Term
| Equine Protozoal Encephalomyelitis Clinical Pathology |
|
Definition
|
|
Term
| Equine Protozoal Encephalomyelitis Diagnosis |
|
Definition
Serum EPM is good negative indicator for lack of disease
CSF good positive indicator for disease with specific IgG test |
|
|
Term
| Equine Protozoal Encephalomyelitis Treatment |
|
Definition
sulfa/pyrimethamine
Diclazuril
Ponazuril |
|
|
Term
| Equine Protozoal Encephalomyelitis Prognosis |
|
Definition
early detection and treatment improves prognosis
most return to normal |
|
|
Term
| Equine Parasitic Encephalomyelitis Pathogenesis |
|
Definition
aberrant parasite migration to the brain
Strongylus vulgaris, Setaria, Hypoderma, Halicephalobus gingivalis, Draschia megastoma |
|
|
Term
| Equine Parasitic Encephalomyelitis History |
|
Definition
acute onset of focal asymmetric neuro signs
may have good deworming history |
|
|
Term
| Equine Parasitic Encephalomyelitis Signs |
|
Definition
normal physical exam
signs correspond to area of brain/cord involved |
|
|
Term
| Equine Parasitic Encephalomyelitis Clinical Pathology |
|
Definition
may have eosinophils in CSF
nonspecific |
|
|
Term
| Equine Parasitic Encephalomyelitis Diagnosis |
|
Definition
CSF has xanthochromia (yellowing), increased RBC, mononuclear inflammatory cells, rarely eosinophils
necropsy is only definitive diagnosis
response to treatment |
|
|
Term
| Equine Parasitic Encephalomyelitis Treatment |
|
Definition
fenbendazole
trichlorfon
diethylcarbamazine
ivermectin doesn't reach high enough levels in CNS without being toxic
antiinflammatories (NOT STEROIDS)
DMSO diluteld in saline
NSAIDs |
|
|
Term
| Equine Herpesvirus Encephalomyelitits Virus |
|
Definition
|
|
Term
| Equine Herpesvirus Encephalomyelitits Pathogenesis |
|
Definition
vascular infarction of brain/cord
immune mediated vasculitis type III hypersensitivity (Ag-Ab deposition results in vascular endothelial damage) |
|
|
Term
| Equine Herpesvirus Encephalomyelitits History |
|
Definition
recent changes on farm
new arrivals
recent viral respiratory disease on farm
recent storm of last trimester abortions
acute onset of ascending paralysis mostly in the hindlimbs |
|
|
Term
| Equine Herpesvirus Encephalomyelitis Signs |
|
Definition
urinary incontinence
paracute to acute onset
paresis, ataxia
usually symmetric due to multifocal nature of lesion
lower motor neuron urinary bladder
penile/vulvar flaccidity
decreased tail tone, perineal hypo/analgesia
rapid stabilizability |
|
|
Term
| Equine Herpesvirus Encephalomyelitits Clinical Pathology |
|
Definition
| eosinophilinc intranuclear inclusion bodies |
|
|
Term
| Equine Herpesvirus Encephalomyelitits Diagnosis |
|
Definition
CSF reflects acellular infarction
CSF=xanthochromia, increased protein, normal cell count and differential, EHV-1 titer positive
Serum titer for EHV-1
necropsy
virus isolation in nasopharyngeal swabs, buffy coat of EDTA blood
PCR |
|
|
Term
| Equine Herpesvirus Encephalomyelitits Treatment |
|
Definition
corticosteroids (dexamethasone)
antibiotics for secondary bacterial infection in bladder and lungs
supportive care
Acyclovir is caught early (not cheap) |
|
|
Term
| Equine Herpesvirus Encephalomyelitits Prognosis |
|
Definition
fair is still standing
guarded if recumbent
recovery is good if don't die |
|
|
Term
| Equine Herpesvirus Encephalomyelitits Prevention |
|
Definition
no vaccine licensed for protection against neurologic form of EHV-1
vaccines are available
don't vaccinate horses that are showing signs |
|
|
Term
| Equine Degenerative Myeloencephalopathy Pathogenesis |
|
Definition
familial predisposition from sires
suspected dietary vitamin E deficiency causes signs in predisposed individuals |
|
|
Term
| Equine Degenerative Myeloencephalopathy History |
|
Definition
normal at birth
signs start within first year
moderately to rapidly progressive
may be farm and/or familial problem |
|
|
Term
| Equine Degenerative Myeloencephalopathy Signs |
|
Definition
symmetrical
ataxia, paresis, diffuse hyporeflexia
chronic, insidious progression from wobbler-like signs to recumbent and unable to rise within a few months |
|
|
Term
| Equine Degenerative Myeloencephalopathy Diagnosis |
|
Definition
based on rule outs
very rare |
|
|
Term
| Equine Degenerative Myeloencephalopathy Treatment |
|
Definition
|
|
Term
| Equine Degenerative Myeloencephalopathy Prognosis |
|
Definition
|
|
Term
|
Definition
Clostridium tetani
puncture wound, foot abscess, laceration, tail docking, site of infection often never found
organisms produce neurotoxins (tetanospasmin and tetanolysin)
neurotoxin results in blockage of presynaptic inhibitory interneurons
tetanic appearance due to inability to inhibit neuromuscular actions
bound toxin can't be displaced by antitoxin |
|
|
Term
|
Definition
often don't find a wound
horses are very sensitive
poor vaccination history |
|
|
Term
|
Definition
apprehensive attitude
hypersensitivty to light and sound
stiff altered gait
3rd eyelid flicks across the eye
rigid musculature |
|
|
Term
|
Definition
clean and debride wound
penecillin for 30 days
tetanus antitoxin to prevent further toxin binding
supportive care in dark, quiet environment, cotton balls in ears, hand/tube feed and water |
|
|
Term
|
Definition
good if standing
poor is recumbent
die of respiratory muscle failure |
|
|
Term
|
Definition
toxoid annually
if tetanus never given before and has an injury, give toxoid and antitoxin
give toxoid if the animal got vaccinated a while ago
if vaccinated in the last month they should be fine |
|
|
Term
|
Definition
Clostridium botulinum
ingestion of pre-formed toxin in feed/grass/hay
toxicoinfectious botulism=ingestion of spores-->organism grows in gut lumen-->exotoxin production-->toxin absorption from gut
wound botulism= wound contaminated with organism-->exotoxin production
organism produces exotoxin
toxin blocks Ach release at neuromuscular junction presynaptic neuron
weakness/paresis due to muscular weakness from failure of LMN input into muscle action and tone
bound toxin can't be displaced by antitoxin |
|
|
Term
|
Definition
weakness
dysphagia, decreased tone of tongue eyelid tail
stiff stilted gait
muscle tremors
progressive tetraparesis to tetraparalysis |
|
|
Term
|
Definition
antisera available but expensive
respiratory support
prophylactic antibiotics
supportive care |
|
|
