Vestibular Patient Flashcards
What is the physiologic function of the vestibulochoclear system?
Maintain posture and balance relative to the head, body and limbs, detects acceleration and deceleration and coordinates eye movement
List some of the structures involved?
Bulla, pons, medulla, horizonal canal, inner ear, vestibular apparatus, choclea
How do hair cells help detect motion?
movement pulls on the hair cells and changes the rate of fire
Explain the purpose of each of the folllowing structures:
Semicircular canals
Saccule
Utricle
Ampulla
Semicircular canals - x, y and z plane
Saccule - vertical acceleration
Utricle - horizonal acceleration
Ampulla - rotational movement
What parts of the brain are considered central vestibular?
medulla and cerebellum
The vestibulospinal track is the only ____ track. (Contralateral or ipsilateral)
Ipsilateral
What role does the vestibular system have in eye movement?
Physiologic nystagmus and oculocephalic reflex
What nerves run through the middle ear?
Cranial nerve 7: Facial Nerve
Sympathetic to eye
What are the signs of horners sysndrome?
Miosis, ptosis, enophthalmos, 3rd eyelid protrusion
What are some clinical signs of vestibular disease?
Abnormal posture, vestibular ataxia, strabismus, nystagmus
How is nausea related to the inner ear?
Chemoreceptor trigger zone and vomiting center right next door
What are some treatments for nausea?
-Antihistamines (Target vestibular nucleus
-Ondansetron (target seratonins in CTZ)
-Metoclpramise (target dopamine)
-Maropitant (targets on CTZ and vomit center Neurokinin-1)
What are the goals of the neurologic exam in reference to vestibular dysfunction?
Localize (central versus peripheral), establish differntial diagnosis, determine diagnostic procedure and prognosis
What is the consciousness level of peripheral vs central vestibular disease?
Peripheral: alert but disoriented
Central: alert, disoriented, obtunded, stupor or coma
What can a patient be obtunded and stuporous with central vestibular?
The RAS system is right next door so if the lesion is large enough it may be affected as well
What does the gait look like in a vestibular patient?
asymmetric input, head tils, circle, rolling, leading (toward lesion) and vestibular ataxia
When a patient loses balance and is found in the archer pose, where is the lesion?
flexed leg is where the lesion is located (Lose tone on side with injury)
Which gait says peripheral versus central?
Peripheral: vestibular ataxia and good strength
Central: vestibular ataxia and tetra or hemiparesis
What are the key parts of the neuro exam that tell peripheral versus central?
Consciousness and postural reactions
What is the postural reaction of peripheral versus central vestibular?
Peripheral: no deficit, good strength
Central: ipsilateral deficit and hemi/tetra paresis
What is the common vestibular strabismus location?
Abnormal eye position, ventrolateral, resting or positionally induced
What is the pathologic nystagmus?
spontaneous at rest, positional induced, rotary, horizonal (central or peripheral) or vertical (central), fast phase, jerk away from lesion
What kind of nystagmus is associated with peripheral or central?
Peripheral: horizonal rotary or fast away
Central verticle or horizonal, change directions
Cranial nerve deficits central vs peripheral?
Peripheral: no other than 7, sympathetic eye
Central 5-7, sympathetic rare
Describe the following for a central vestibular lesion:
Mentation:
Posture:
Gait:
Postural Reaction Deficit:
CN:
Nystagmus:
Mentation: Alert, obtunded, stupor or coma
Posture: head tilt ipsilateral and can be contralateral
Gait: Ataxia and para or tetra paresis
Postural Reaction Deficit: Deficit on ipsilateral side
CN: 5-7 (facial, vestibulo coclear)
Nystagmus: vertical or horizonal, change direction
Describe the following for a peripheral vestibular lesion:
Mentation:
Posture:
Gait:
Postural Reaction Deficit:
CN:
Nystagmus:
Mentation: Alert, disoriented
Posture: head tilt ipsilateral
Gait: Ataxia, strong,
Postural Reaction Deficit: None
CN: Only 7
Nystagmus: Horizonal, rotary
What are the most common causes of Peripheral vestibular disease?
Otitis media/interna, polyp, PSOM, Idiopathic, ototoxic drug, hypothyroidism
After determining that it is peripheral how do you procede?
Otoscopic exam, rad bulla, CT (good bony), BAER, Myringotomy
*Can progress to meningitis or abscess
What are some causes of otitis media?
Infectious: pseudomonas aeruginosa, staph pseudointermedius, ecoli or klebsiella
Non-infectious: PSOM (secretory), glue ear, otitis with effusion
How is otitis media treated?
Topical (careful)
oral - clavamox or batryl
myringotomy
TECA-Bo
Describe an myringotomy and its indications
Poke a hole in the middle ear to release fluid and pressure
Chronic infections, intact tympanum, fluid or buldging membrane
What is a polyp, signs and how do you treat it?
Inflammatory disease - middle ear, nasopharync or combo
Signs: upper airway breathing heavy
Pull off
What are some common types of aural neoplasia?
Fibrosarcoma, chondrosarcoma, osteosarcoma, SSC
Surgical resection or radiation
Who gets idiopathic vestibular disease, when and how long does it take to clear?
Adult cat and older dogs
Acute
remission 1-2 weeks
Cuterebra?
What kinds of things are ototoxic?
Aminoglycosides (gentamicin, amikacin neomycin), polymixin, furosamide, NSAID, Chemo, chlorohex, detergent prpylen glycol
What is the prognosis for vestibular peripheral?
good if treat early and aggressive
guarded if cancer or ototoxicity
permancent head tilt, kcs, horner or facial paresis
What are some major causes of central vestibular disease?
Hypothyroid, neoplasm, thiamine deficiency, infectious, brainstem trauma, metronidazole, stroke
How do you approach diagnostics once you know it is central vestibular disease?
MRI, CSF tap, Reffer
Hypothyroidism can cause either?
peripheral: myoxomatous compression CN, polyneuropathy
Central - infarce, cns demylination
What kind of intercranial neoplasia are common?
meningioma, chorid plexus,
Treat rescetion or radiation
Thiamine Deficiency in central?
Signs: seizure, mentation, vestibular
Cause: diet
treat: balance diet
What about metronidazole toxicity?
> 60mg/kg/day
GABA
treatment? Diazepam
Lead other toxin
What about vascular cause?
Sigs: acute
Cause: cterebra?, infarct, thrombocis, hypothroidism
