Vestibular Disease

Anne E. Chauvet, DVM, DACVIM (Neurology)


Neuroanatomy

Brainstem and flocular 
Nodular lobes of the cerebellum
Cerebellar peduncles
Caudal Fossa

  Vestibular Clinical Signs  

Head tilt – ipsilateral
Leaning/falling/tilting – ipsilateral
Ataxia
Vomiting and salivation –usually more prominent in peripheral disease
Nystagmus – labeled according to fast phase that is away from lesion
Strabismus - ipsilateral

Central
Peripheral
Loss of balance/ataxia Yes Yes
Head tilt Yes Yes
Falling or rolling Yes Yes
Nystagmus All direction All directions
Positional/non Mostly nonpositional
Disconjugate + conjugate Conjugate
Strabismus Yes Yes
Cranial nerve deficits Yes VII only
Horner’s syndrome Less likely Yes
Cerebellar disease Yes No
Mental alteration Yes No
Proprioceptive deficits/paresis Yes No

 
Diagnosing vestibular disease:

Peripheral disease:

Otoscopic examination
Endoscopy
BAER
Skull/bullae radiographs
Myringotomy
Culture and Sensitivity

Central disease

Thoracic radiographs/metastasis check
Complete blood work up
Titers: toxoplasmosis, distemper, FelV, FIV, cryptococcus, FIP, tick titers, etc.
BAER, EEG, SEP
CT or MRI
CSF tap

Vestibular diseases DAMNIT!

1.  Geriatric vestibular disease

Degeneration of the receptor organ or the chain of ossicles in the middle ear
Progressive loss of hearing

2.       Congenital peripheral vestibular disorder

Uncommon
German Shepherd Dog and others
<12 weeks old
Signs may regress in 3-4 months
Head tilt
No pathological nor physiological nystagmus
Normal histopathology

3.       Congenital nystagmus

Pendular
Unknown etiology
Guernsey and Holstein cows
Ayshire bulls
Siamese cats

4.  Neoplasia

Older animals >4 years old
Compressive vs invasive
Slow onset and progressive usually
Most common in dogs
Meningioma is most common in dogs and cats
Lymphoma more common in large animals
Primary effects = compression + infiltration
Secondary effects = edema, increase in ICP
Signs depend on tumor location and extent

5.        GME = granulomatous meningoencephalomyelitis

Unknown cause, suspect immune mediated
Non suppurative perivascular inflammation
Young to middle age dogs
Female>Male
Small breeds more so
Guarded to poor prognosis because diagnosis only confirmed by histopathology
Ocular form is uncommon
Focal form – cerebellopontine angle
Treatment: Steroids, Immuran, IgG, Radiation

6.       Feline viral disorders

FIV and FelV
Signs depend on location
Serum and CSF titers together
Histopathology
Poor prognosis

7.       FIP

Corona virus
Immune mediated vasculitits of CNS
Clinical signs-multisystemic
Slow and progressive
Caudal fossa syndrome, seizures, myelitis
Ocular
Hypergammaglobulinemia
Cytoxan, steroids—fatal

8.       Canine distemper encephalitis

Parmyxovirus
Not always respiratory signs
Not always neurological
Post vaccinal
Old dog encephalitis:dementia, ataxia, central blindness, rarely seizures
Young dog: seizures, myoclonus, transverse myelitis
Diagnosis by IFA, titers on serum and CSF: IgG, IgM and SNA (Cornell)
Symptomatic treatment: steroids, HrIgG
Permanent deficits

9.       Protozoal and Fungal Diseases

Cats: toxo and crypto
Dogs: blasto, aspergillosis, coccidiomycosis, toxo, neosporosis
Equine: EPM

10.   Toxoplasmosis/Neosporosis

Multisystemic
Immunosupression predisposes
Encephalitis, radiculitis, myelitis, myositis
Titers in Colorado: IgG and IgM
TMS-pyrimethamine-folic acid

11.   Otitis Media/Interna

Acute or chronic
Some breeds are predisposed
Horner’s syndrome + CN VII
Deafness if bilateral disease
BAER
Systemic antibiotics
Saline cleanings
Damage may be permament

12.   Abscess

Large animals more so
Secondary to bites
Focal signs
Systemic antibiotics and steroids

13.   Feline idiopathic vestibular disease

Sudden onset
All ages
Late summer and fall
Unknown etiology: cuterebra
No treatment
Good prognosis

14.   Metronidazole toxicity

Unknown mechanism
High dosages and long durations
Never exceed 7.5 mg/kg TID
Sudden onset of vestibular disease, seizures, disorientation
Discontinue drug=treatment
Time

15.   Ototoxicity

  • Aminoglycosides
  • Treatment= withdraw drug
  • Permanent deafness
  • Vestibular signs may resolve

Vestibular Emergency

IV diazepam
IV acepromazine at 0.002 mg/kg to 0.02 mg/kg
Meclazine
Padding – especially on side of lean
Steroids?
Differentiate from seizure