1. Neurologic Emergencies: vestibular events
Todd M. Bishop, DVM, DACVIM (Neurology)
Thursday February 6th, 2014

2. Goals of this mini-lecture
Recognize the clinical signs
Correlate with the neurologic exam
Perform point-of-care diagnostic testing
Provide initial therapeutic intervention(s)
Know when to discuss referral
* Making anatomic and differential diagnoses will NOT be emphasized in this talk but the details are in the notes.

3. What the client sees … Head tilt Balance loss; walking as if “drunk”
Jerking eye movements
Eyeball deviation
Nausea, vomiting, drooling
Wide-based stance
Inability to stand
Listing, leaning, falling to one direction
Rolling to one side (“alligator rolling”)

4. What you should look for …
Mentation change
Cranial nerves abnormalities
Strabismus, nystagmus
Gait and Posture alteration
Head tilt, ataxia
Postural reactions deficits
Delayed hopping and placing

5. The quick and dirty When is it in the brain (central vestibular)?
Mentally inappropriate
Vertical nystagmus
Changing direction nystagmus
Right to left
Vertical to horizontal
but NOT horizontal to rotary to the same side!
Postural reaction deficits

6. Etiologies* PERIPHERAL Idiopathic Otitis M/I Hypothyroidism
Ototoxicity
Trauma
Neoplasia
CENTRAL
Metabolic
Malformative
Inflammatory
Infectious
Infarction (vascular)
Neoplastic
Degenerative
* Remember this is NOT the emphasis of this lecture!

7. Diagnostic testing Referral Primary Care MRI > CT scan CSF tap
CBC/Chem/UA/CXR/BP
Thyroid panel
Otoscopic exam
Cytology and culture
Myringotomy
Sedated skull radiographs
Referral
MRI > CT scan
CSF tap

8. Basic Medical Work-up CBC/Chem/T4/UA Thoracic radiographs
A BLOOD PRESSURE

9. Soapbox ALERT !
I can not emphasize the importance of the basic medical work-up enough !
You may find the cause or a complicating disease process !!
This MUST be done before advanced testing can be considered !!!
People … it makes financial sense !!!!
with one exception … same day referral
marvimarti.com

10. Thyroid testing A simple total T4 will suffice for cats
Dogs need a complete thyroid panel
HYPERT4→high BP→stroke→vestibular signs
hypoT4→atherosclerosis→stroke→vestibular signs
hypoT4→abN metabolism in VIII→vestibular signs

11. Otoscopic exam

12. External ear cytology & culture

13. Myringotomy (tympanocentesis)

14. Sedated skull radiographs
Textbook of Veterinary Diagnostic Radiology- Thrall

15. * Regardless of etiology!
Empiric therapies *
IV fluids
Antibiotics
Dimenhydrinate (Dramamine)
Meclizine (Bonine, Antivert)
Cerenia
Benzodiazepines
Corticosteroids?
* Regardless of etiology!

16. Intravenous Fluids Rehydrate after vomiting
Maintain vascular volume (anorexia)
Combat ongoing losses (drooling)
Promote cerebral profusion (especially important in ischemic cerebrovascular disease)

17. Antibiotic therapy Common otic flora
Strep, Staph, Malassezia
Base treatment on cytology and culture
Empiric treatment options:
Cephalosporin
Amoxicillin
Fluoroquinolone
Fluconazole

18. Dimenhydrinate
Antihistaminic (H1), antiemetic and anticholinergic effects
Acetylcholine stimulation of the vestibular and reticular systems may be blocked
4-8 mg/kg PO SID-TID
12.5 mg PO SID-TID (cat)
25–50 mg PO SID-TID (dog)
essex1.com

19. Meclizine Antihistamine with sedative & antiemetic effects
H1 receptor blocker
25 mg / dog PO SID x 3-4 days
12.5 mg / cat
insightpharma.com

20. Cerenia Maropitant (mar-oh-pit-ent) Citrate
Neurokinin (NK1) Receptor Antagonist
Inhibits Substance P a neurotransmitter involved in vomiting
Acts at the vomiting center to treat motion sickness
8 mg/kg PO q 24h for up to 2 consecutive days
vinoenpaso.at

21. Benzodiazepines Diazepam or Midazolam : Sedative effect
0.5 mg/kg IV bolus
0.5 mg/kg/hr IV CRI over hrs
Sedative effect
Inhibitory neurotransmitter in the vestibular system
Metronidazole toxicosis antidote
bipolarblast.wordpress.com

22. Corticosteroids
Should ideally be employed only after a definitive diagnosis has been made
Can be added if all other empiric therapies are failing and clients not interested in referral
If using empirically consider an anti-inflammatory dose (ie. Prednisone 0.5 mg/kg BID)

23. When to refer a case? After a patient is stabilized
Once preliminary testing is done
When there is no response to general supportive care described above
When central disease is suspected