Contributors: Laurent Garosi, Rosanna Marsella

 Species: Feline   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading

Introduction

  • Cause: disturbance of the central or peripheral vestibular system.
  • May be secondary or idiopathic.
  • Signs: ataxia, falling/rolling, leaning to one side, head tilt (unilateral) or wide excursion of the head from side to side (bilateral), circling, nystagmus.
  • Diagnosis: signs.
  • Treatment: depends on cause.
  • Prognosis: reasonable to good, depending on cause.
    Follow the diagnostic tree on Vestibular disease.

Presenting Signs

  • Ataxia.
  • Falling/rolling.
  • Leaning to one side.
  • Head tilt (unilateral vestibular).
  • Wide excusion of the head from side to side (bilateral vestibular).
  • Nystagmus.

Age Predisposition

  • Mean age for idiopathic disease is 4 years.

Breed Predisposition

Pathogenesis

Etiology

Central vestibular disease

Peripheral vestibular disease

  • Otitis media Otitis media:
    • Extension of otitis externa Otitis externa.
    • Retrograde infection via eustachian tubes.
    • Hematogenous.
  • Nasopharyngeal polyps Nasopharyngeal polyp.
  • Idiopathic.
  • Neoplasia.
  • Congenital disease.
  • Toxicity:
    • Aminoglycoside antibiotics.
    • Topical iodophors.
    • Chlorhexidine Chlorhexidine.
  • Trauma:
    • Fracture of temporal bone.
    • Tympanic bulla damage.

Timecourse

  • Acute onset over days.
  • Signs may persist for weeks or months.

Diagnosis

Presenting Problems

  • Ataxia.
  • Nystagmus.
  • Head tilt.
  • Wide excursion of the head from side to side.

Client History

  • Ataxia/rolling.
  • Head tilt.
  • Wide excursion of the head from side to side. 
  • Nystagmus.

Clinical Signs

  • Ataxia.
  • Wide base stance.
  • Head tilt (to side of lesion with unilateral vestibular disorder    Otitis media: tilted head  ), head tilt can be contralateral with lesion affecting the caudal cerebellar peduncle, fastigial nucleus and/or flocculonodular lobes of the cerebellum.
  • Wide excursion of the head from side to side with bilateral peripheral or central vestibular disorder.
  • Nystagmus (fast phase away from lesion):
    • May be detected by clinical examination.
    • May be detected by ophthalmoscopic examination only.
    • May only be abnormal positional nystagmus.
    • Vertical nystagmus and nystagmus that changes direction on changing position of the head can only be seen with central vestibular disorder.
  • Leaning, rolling or falling to side of lesion.
  • No postural weakness.
  • Circling towards lesion.
  • Mild hypertonia and hyperreflexia in limbs on side of lesion.
  • Ventrally deviated eyeballs if head raised (strabismus).
  • Horner's syndrome Horner's syndrome may be present with middle ear disease (tumor, otitis or polyps).
  • Signs associated with central lesion, eg abnormal mentation, UMN  hemiparesis, general or reduced proprioceptive ataxia, deficits of cranial nerves V to XII (other than VII and VIII).

Diagnostic Investigation

Radiography

Other

  • Imaging techniques:
    • Computed tomography (CT) or magnetic resonance imaging (MRI) may be very useful for imaging central disease or otitis media Ear: otitis media (right side) - CT scan .
  • Otoscopic and pharyngeal examination under general anesthesia:
    • Otitis externa Otitis externa with extension by rupture of tympanic membrane.
    • Tympanic membrane may appear discolored by fluid in middle ear.
    • Myringotomy Myringotomy with a 20-gauge spinal needle to obtain samples for cytology and culture if the tympanic membrane is intact, but bulging or of an abnormal color.
  • Swabs:
    • Swabs for cytology and culture (aerobic, fungal and yeast) from the middle ear if the tympanic membrane is ruptured.
  • CSF analysis  Cerebrospinal fluid: sampling (nucleated cell count Cerebrospinal fluid: cell count and differential, cytology Cerebrospinal fluid: cytology, total protein concentration, PCR for infectious titer PCR (Polymerase chain reaction)).

Differential Diagnosis

  • Otitis media without vestibular involvement.

Treatment

Initial Symptomatic Treatment

  • Depends on cause

Idiopathic

  • No evidence to suggest that any treatment affects outcome of disease.
  • Meclizine (6.25 mg PO q12h) and/or diazepam Diazepam (1-2 mg PO q8h) are sometimes helpful in decreasing signs associated with acute vestibular disorder (nausea, anorexia, anxiety, and, in some instances, the severity of the head tilt and ataxia).

Otitis media

  • Myringotomy Myringotomy (puncture of tympanic membrane (if intact) to relieve pressure and obtain fluid sample for diagnosis).
  • Performed under general anesthesia.
  • Clean external ear canal and then puncture tympanic membrane in ventrocaudal aspect with 22 guage spinal needle.
  • Aspirate fluid sample and flush gently with 0.2-0.4 ml sterile saline.
  • Treat with broad spectrum systemic antibiotics Therapeutics: antimicrobial drug for a minimum of 4-6 weeks. Choice of antibiotic is dictated by results of culture/sensitivity if available; if not amoxicillin/clavulanate Amoxicillin Clavulanate, cephalosporine or fluoroquinone are reasonable choices to consider.
    Delay topical therapy for 4-5 days if myringotomy performed.
  • Surgical drainage and debridement via bulla osteotomy Bulla osteotomy if refractory to medical treatment.

Nasopharyngeal polyp

Outcomes

Prognosis

  • Good to reasonable depending on cause.
  • Most idiopathic cases improve over several days and may continue to improve for up to 8 weeks.
  • Good prognosis if underlying disease identified and treated eg otitis media, or nasopharyngeal polyp.
  • Congenital cases may stabilize and occasionally signs regress then recur.

Expected Response to Treatment

  • Resolution of nystagmus over days to weeks. Reducing ataxia and head tilt.
    Many animals with on-going disease learn to accommodate and clinical signs may reduce with time.

Reasons for Treatment Failure

  • Underlying condition not diagnosed or treated adequately.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Negrin A, Cherubini G B, Lamb C et al (2010) Clinical signs, magnetic resonance imaging findings and outcome in 77 cats with vestibular disease: a retrospective study. J Feline Med Surg 12 (4), 291-299 PubMed.
  • Rossmeisl J H Jr. (2010) Vestibular disease in dogs and cats. Vet Clin North Am Small Anim Pract 40 (1), 81-100 PubMed.
  • Thomas W B (2000) Vestibular dysfunction. Vet Clin North Am Small Anim Pract 30 (1), 227-249 PubMed.
  • LeCouteur R A & Vernau K M (1999) Feline vestibular disorders Part 1 - anatomy and clinical signs. J Feline Med Surg (2), 71-80 PubMed.
  • Vernau K M & LeCouteur R A (1999) Feline vestibular disorders Part 2 - diagnostic approach and differential diagnosis. J Feline Med Surg (2), 81-8 PubMed.
  • Schunk K L (1988) Disorders of the vestibular system. Vet Clin North Am 18 (3), 641-665 VetMedResource.
  • Burke E E, Moise N S, de Lahunta A (1985) Review of idiopathic feline vestibular syndrome in 75 cats. JAVMA 187 (9), 941-3 PubMed.

Other sources of information

  • de Lahunta A, Glass E (2009) Vestibular system - special proprioception. Veterinary Neuroanatomy and Clinical Neurology. 3rd edn. W B Saunders, Elsevier, St Louis, Missouri, pp 319-347.
  • Munana K R (2004) Head tilt and nystagmus. In: BSAVA Manual of Canine and Feline Neurology. 3rd edn. S R Platt & N J Olby eds. BSAVA, pp 155-171.

Further Reading 

The Webinar Vet - Understanding Vestibular Syndrome

Other Sources of Information