Term
| what is dizziness defined as? |
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Definition
| any disturbed sense of relationship to space. it is nonspecific and unsystematized - requires a hx. |
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Term
| what is vertigo defined as? |
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Definition
| a specific type of dizziness, a sensation of spinning or turning w/in your environment or vice versa in any plane. |
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Term
| what is the function of the vestibular system? |
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Definition
| to maintain balance and equilibrium in the context of motion and gravity |
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Term
| what causes the sensation of continuous head motion or vertigo? |
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Definition
| asymmetric impulses from the 2 opposing vestibular nuclei to the cerebellum and thus the cortex. |
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Term
| how does the body compensate and adapt to vertigo? |
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Definition
| the first stage of compensation is called the *cerebellar clamp, where the cerebellum sends back inhibitory signals to the vestibular nuclei in response to their asymmetric impulses. second, the cerebral cortex then begins to get info from the eyes and proprioceptive system (2 other sources of sense of balance). |
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Term
| what affecting the eyes can cause nonsystematized dizziness? |
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Definition
| muscle imbalance, refractive errors, and simple glaucoma |
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Term
| what affecting the proprioceptive system can cause nonsystematized dizziness? |
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Definition
| pellagra, chronic alcoholism, pernicious anemia, and tabes dorsalis |
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Term
| what affecting the CNS can cause nonsystematized dizziness? |
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Definition
| 1) mild cerebral anoxia (caused by: arteriosclerosis, hypertensive cardiovascular disease, chronic HTN, anemia, paroxysmal arterial fibrillation, aortic stenosis w/insufficiency, heart block, carotid sinus syndrome, simple syncope, and postural hypotension). 2) infection (due to: meningitis, encephalitis, brain abscess, syphilis). 3) trauma. 4) tumors. 5) migraine. 6) petit mal epilepsy. |
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Term
| are there specific pharmacologic tx available for most chronic vestibular disorders? |
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Definition
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Term
| what are the 3 categories for use of medication to treat vestibular disorders? |
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Definition
| 1) general suppressors of the CNS. 2) pharmacologic tx of specific conditions which cause vestibular symptoms (meniere's, migrane, autoimmune). 3) tx of reactive depression caused by the troubling vestibular symptoms. |
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Term
| what are the peripheral vestibular disorders? |
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Definition
| meniere's disease, labyrinthitis, vestibular neuronitis, benign paroxysmal positional vertigo, perilymph fistula, superior canal dehiscence, and autoimmune vestibulopathy |
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Term
| what is the syndrome triad associated w/meniere's disease? |
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Definition
| 1) vertigo usually preceded by aural fullness and typically lasting 30 min to 24 hours. 2) tinnitus - most commonly hissing. 3) hearing loss, usually low frequency and fluctuating. these symptoms may vary, depending on whether cochlear, vestibular, or cochleovestibular. |
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Term
| what characterizes the incidence of meniere's disease? |
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Definition
| onset is 3rd-4th decade, equal among sexes, and usually unilateral - but 20-40% are bilateral. |
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Term
| what are the diagnostic modalities for meniere's disease? |
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Definition
| audiogram, tympanogram, ENG, BSER (if indicated), VEMP (vestibular evoked myogenic potential), MRI of IAC w/gadolinium if indicated, RAST/BS/thyroid function/lipids/VDRL, and autoimmune studies (CBC, sed rate, rheumatoid factor, antinuclear Ab (ANA), and anticochlear Ab. |
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Term
| what is significant about using an MRI to image the IAC? |
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Definition
| this is the *gold standard* for r/o a brain tumor (schwannoma, neurofibroma) which can mimic the migrane variant of meniere's disease or MS. |
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Term
| what is the most common etiology of meneire's disease, if one can be found? how is this tested for? |
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Definition
| food allergy (sensitivity), which is non-IgE mediated. this is tested for using food provocative testing/food elimination diet (take food out for 5 days, then bring it back heavily) starting w/milk products, caffeine/chocolate, and wheat. |
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Term
| what is the pathophysiology of meniere's disease? |
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Definition
| distention of the membranous labyrinth and cochlear duct either due to overproduction of endolymph or defective reabsorption. |
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Term
| what other etiologies may be identified for meniere's disease after allergy? |
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Definition
| *DM, *thyroid dysfunction, hyperlipidemia, autoimmune disorder, viral, and syphilis. |
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Term
| what is the association of meniere's disease w/nystagmus (involuntary movement of the eye)? |
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Definition
| meniere's disease is associated w/peripheral nystagmus - the slow component of which is always in the direction of endolymphatic flow. |
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Term
| why is nystagmus tested for in possible meniere's disease pts? how is this done |
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Definition
| this is to determine if there is a hyper/hypofunctioning inner ear. the pts head is tilted back, bringing the horizontal canal up vertical (though it will still give you horizontal nystagmus - the horizontal canal is always used b/c it is the closest to the periphery: most available for testing). cold in the pts ear should create nystagmus towards the opposite ear and warm should create nystagmus toward the same side as the ear being tested (COWS - due to convection currents). |
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Term
| how is meniere's disease treated medically? |
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Definition
| *low salt/low caffeine diet. *diuretics (dyzide or diamox - lower production of CSF, which endolymph is very similar to). *vestibular suppressants: antihistamines (antivert, dramamine), phenothiazines (benadryl, phenergran - antihistaminic+anticholinergic effect), *anticholinergics (probanthine, scopalomine, atropine), *sympathomimetics (amphetamine, ephedrine - not antivertiginous, but increase efficiency of anticholinergics), *benzodiazepines (valium - enhances 1st stage of cerebellar clamp+antidepressant, klonopin, xanax), *steroids (prednisone burst through direct application to round window), *antibiotics (streptomycin IM - destroys labyrinth, only for bilateral dz and garamycin directly applied to the round window), *immunosuppressant drugs (prednisone, methotrexate, enbrel, remicade), *antidepressants (zoloft, prozac), and if severe vertigo/unresponsive to benzodiazepines: droperidol IV or vontrol orally (for nausea). |
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Term
| what are the ototoxic drugs? |
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Definition
| lasix (furosemide + other loop diuretics) and aminoglycosides (garamycin - cumulative) - DO NOT combine unless the pt is going to die, b/c this combination will cause permanent deafness. salicylates and quinine may cause a reversible tinnitus. |
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Term
| how is meniere's disease treated surgically? |
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Definition
| endolymphatic shunt - no longer done, sacculotomy (tack operation - no longer done), vestibular nerve section (95% effective: the vestibular function will stop, but hearing should still function), and destructive procedures (transmeatal labyrinthectomy, transmastoid labyrinthectomy, or chemical labyrinthectomy) |
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Term
| what characterizes labyrinthitis? |
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Definition
| severe vertigo exacerbated by head movement - viral is the most common form, this is often preceded by a URI, usually no hearing loss, and symptoms usually abate in 48-72 hours w/gradual return to normal balance in 6-8 wks. |
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Term
| what is tx for labyrinthitis? |
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Definition
| acute phase: antihistamines, benzodiazepines, and anticholinergics. encourage gradual weaning of suppressants to promote central adaptation. 1/3 of elderly pts will need vestibular rehabilitation to achieve central compensation. |
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Term
| what is vestibular neuronitis? tx? |
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Definition
| theoretically a viral inflammation of the vestibular nerve, or possibly another form of labyrinthitis. pts will have a hx of a precipitating viral infection and episodic exacerbations for vertigo - not accompanied by hearing loss, aural fullness, or tinnitus. tx is the same as viral labyrinthitis + antiviral therapy for recurrent cases. |
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Term
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Definition
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Term
| what is benign paroxysmal positional vertigo (BPPV/canalithiasis)? |
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Definition
| this most common adult form of vertigo is precipitated by head movement and lasts 1-2 min. it may be associated w/head trauma (b/c it is due to otolithic debris from the ampulla getting into the semicircular canals and setting up a current - usually the posterior canal), the dix-hallpike position test is diagnostic, and it is usually self-limiting in 6-12 weeks (except in the elderly). |
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Term
| how is the dix-hall test performed? |
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Definition
| the pt sits on the side of the table, brings their feet up on the table, and a pillow is placed under their back. the pt then lies down quickly w/their head turned to one side for ~20 sec, then again w/the other side for ~20 sec. nystagmus and vertigo are then monitored for. |
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Term
| what is the difference between peripheral and central nystagmus in the dix-hallpike test? |
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Definition
| there may be a latency period of up to 20 sec for peripheral nystagmus before vertigo begins and it only lasts 20 sec - 1 min. peripheral vertigo is also usually more violent (pt really wants to get out of the position) but is fatigable. central vertigo will start immediately and last as long as the pt is in the offending position. |
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Term
| what are the slow and quick components of nystagmus? how does this related to the dix-hallpike test? |
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Definition
| the quick movement is the eye coming back to midline, the slow movement is in the direction of endolymph. in the dix-hall test, the quick component will always be to the affected ear. |
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Term
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Definition
| no antihistamines or sedatives (will mess w/compensation). specific physical manipulation of the pt will tx BPPV, as the otoliths can be moved back out of the semicircular canals. |
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Term
| what is a perilymphatic fistula? tx? |
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Definition
| sudden vertigo following head trauma, barotrauma, middle ear sx, or vigorous straining = rupture of the oval or round window = leak of endolymph = hearing loss and vertigo. tx: total bedrest for a week. if hearing loss increases (monitored via audiometry) they are taken to the operating room immediately and the leak is closed. |
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Term
| what is superior canal dehiscence? dx? tx? |
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Definition
| dehiscence = opening of the bone overlying the superior semicircular canal. the absence of the bony roof creates a mobile window which transfers pressure changes resulting in deflection of the superior semicircular canal cupula. pts present w/vertical-torsional eye movement and vertigo in response to loud sounds (tullio phenomenon) and have increased middle ear/intracranial pressure. it is confirmed w/high res CT scan and tx: surgical repair of the superior canal. |
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Term
| what is autoimmune vestibulopathy? tx? |
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Definition
| a *bilateral progressive SNHL, often accompanied by loss of vestibular function. it may be associated w/other autoimmune diseases such as RA, psoriasis, ulcerative colitis, and cogan's syndrome (iritis, vertigo, SNHL). hx is the most useful diagnostic tool - pts will have a hx of other autoimmune dz. tx: autoimmune suppressive therapy. |
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Term
| what lab tests are run for autoimmune vestibulopathy? |
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Definition
| CBC, sed rate, rheumatoid factor, antinuclear Ab (ANA), and anticochlear Ab. |
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Term
| what are the central vestibular disorders? |
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Definition
| vertebro-basilar artery insufficiency, posterior fossa migraine variant migrane, vascular loop syndrome, vaso-occlusive disease, MS, and the acoustic neuroma (schwannoma of the 8th CN) |
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Term
| what characterizes vertebro-basilar artery insufficiency? tx? |
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Definition
| this affects the elderly and is associated w/visual disturbances, drop attacks, weakness, diplopia, hallucinations, and headaches and accompanied by n/v. onset of symptoms is rapid and lasts several min. tx: improve blood supply (ASA, persantine, coumadin). |
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Term
| what is posterior fossa migraine? |
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Definition
| this occurs in women 3x more than men, typically between 25-55 y/o and post-menopausal pts may have headache resolution - but still experience associated symptoms. |
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Term
| what symptoms are associated w/the posterior fossa migraine variant vestibular disorder? |
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Definition
| h/a, vertigo (5-60 min), trouble speaking (dysarthria), photophobia, uncoordinated gait, weakness, phonophobia (abnormal sensitivity to sound), abnormal skin sensations, tinnitus, n/v, chronic motion hallucination (mal de debarquement syndrome), hearing loss, and double vision. |
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Term
| how is posterior fossa migraine variant vestibular disorder diagnosed? |
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Definition
| migraine variant (pt does not have to have h/a or h/a may be the aura), symptoms preceded by aura due to ischemia of the basilar artery, other stroke symptoms, MRI/MRA, dx by hx and fam hx of migraines, and neurologic evaluation for migraine tx. |
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Term
| what are common triggers for migraine? |
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Definition
| stress and food: chocolate, aspartame, cured/aged meats, cheese, yeast, canned soup, monosodium glutamate, and pickled/fermented/marinated foods. |
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Term
| what is tx for posterior fossa migraine variant vestibular disorder? |
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Definition
| neurologic evaluation for migraine tx (pharmacy: topamax/klonopin, behavioral: avoid triggers). if accompanied by peripheral unilateral vestibular dysfunction - encourage central compensation w/vestibular rehabilitation therapy (VRT). |
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Term
| what is a vascular loop syndrome? dx? tx? |
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Definition
| this is initiated by physical exertion which may increase the blood flow to the anterior cerebellar artery, which in turn may loop into the IAC. this may mimic meniere's syndrome. dx: IV contrast CT and air cisternography. tx: N VIII decompression. |
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Term
| what is vaso-occlusive disease? |
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Definition
| either acute ischemia of brainstem/cerebellum (symptoms: severe vertigo, n/v, and other central neurologic signs or chronic ischemia (recurrent small brainstem lacunar infarcts in the elderly, often resulting in dysequilibrium and associated w/HTN/ASCVD). dx: MRI + MRI of IAC w/gadolinium. |
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Term
| what is multiple sclerosis? |
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Definition
| a demyelinating disease of the CNS w/multiple signs of CNS dysfunction. vertigo occurs in 50% of pts and visual disturbances in 20%. dx: physical exam, MRI, and spinal tap for elevated gamma globulin and myelin basic proteins. |
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Term
| what is the acoustic neuroma (schwannoma of the 8th CN)? |
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Definition
| a *unilateral progressive SNHL and tinnitus w/lesser than expected discrimination. this can cause vertigo and sudden deafness and may mimic meniere's syndrome. pts may also present w/facial numbness and tingling. pts w/this may be able to walk generally in a straight line w/only a few adjustments. these are benign, but can eventually grow to the point of causing death - thus they are usually left along in elderly pts but cut out in younger pts (hearing can be preserved). |
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Term
| how is an acoustic neuroma diagnosed? |
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Definition
| via MRI of the IAC w/gadolinium (the gold standard). |
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Term
| when might a acoustic neuroma be bilateral? |
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Definition
| when congenital or w/neurofibromatosis type 2 (von recklinhausen's disease) |
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