Contributors: Agnes Delauche, Rosanna Marsella, Harry Scott

 Species: Feline   |   Classification: Diseases

Introduction Pathogenesis Diagnosis Treatment Outcomes Further Reading

Introduction

  • Infection involving the organs of hearing and balance housed within the bony labyrinth.
  • Cause: spread of infection from middle ear or via hematogenous route.
  • Signs: head tilt, circling and nystagmus (vestibular syndrome); unilateral deafness.
  • Diagnosis: history, clinical signs, radiography, neurological assessment.
  • Treatment: broad-spectrum antibiotics.
  • Prognosis: good but high frequency of residual deficits.
    Print off the owner factsheet on Chronic otitis Chronic otitis to give to your client.

Presenting Signs

  • Vestibular syndrome.

Pathogenesis

Etiology

  • Extension of opportunistic infection from otitis media.
  • Hematogenous spread.

Specific

  • Otitis media Otitis media.
  • Bulla irrigation or bulla osteotomy (but only if presence of otitis media).

Pathophysiology

Inner ear disease

  • Infection/trauma/ototoxicity   →   damage to sensory nerve endings within the cochlea, utricle and saccule, or in the ampullae of the semicircular canals   →   deafness and vestibular dysfunction.

Diagnosis

Presenting Problems

  • Vestibular syndrome.

Client History

  • Concurrent otitis media.
  • Recent treatment of otitis by instilling potentially ototoxic agents into ear.
  • Recent bulla irrigation or bulla osteotomy.
  • Head trauma.

Clinical Signs

  • Head tilt, affected side down  Otitis media: tilted head .
  • Circling towards affected side.
  • Horizontal nystagmus, fast component away from affected side.
  • Rolling/falling to affected side.
  • Unilateral deafness present Deafness: acquired, but only detectable with sophisticated audiological tests.
  • Positional ventral strabismus in ipsilateral eye.
  • Vomiting.
  • Concurrent otitis media.
  • General dullness and inappetence.
  • Unilateral facial paralysis, involving upper and lower face but only with concurrent otitis media.
  • Horner's syndrome  Eye: Horners syndrome 01 - affected right eye  Eye: Horners syndrome 01 - normal left eye  Eye: Horners syndrome 02  Eye: Horners syndrome 05 - with left facial nerve paralysis .

Diagnostic Investigation

Other

  • Neurological assessment:
    • Necessary to differentiate from central vestibular involvement .
    • Head tilt.
    • Ataxia.
    • Horizontal nystagmus with quick phase away from side of lesion. With central lesions, positional and vertical nystagmus may be present.
    • With central vestibular lesions, paresis and reduction or absence of proprioception can occur in the ipsilateral limbs. There may also be evidence of multiple cranial nerve involvement.
  • Otoscopic examination:
    • Concurrent otitis media/externa.
  • Brainstem auditory-evoked response (BAER):
    • Evidence of hearing loss.
  • Computed tomography.
  • Caloric stimulation:
    • When otitis interna present, no nystagmus initiated by irrigating external ear canal with warm or cold water.
      Limited usefulness, negative response may occur in many normal animals with the caloric test.
  • Radiography
    • Only of use in identification of otitis media   (but up to 25% of otitis media cases have no radiographic changes), neoplasia Ear: otitis media and polyp - radiograph VD or traumatic injury to skull.

Differential Diagnosis

Peripheral vestibular syndrome

Treatment

Initial Symptomatic Treatment

Standard Treatment

All Of Broad-spectrum, bacteriocidal antibiosis Therapeutics: antimicrobial drug Therapeutics: ear.
And Bulla osteotomy with bulla irrigation, if evidence of unresponsive otitis media.
  • Concurrent keratoconjunctivitis sicca Eye: keratoconjunctivitis sicca resulting from facial nerve paralysis may require long-term therapy with artificial tears.

Monitoring

  • Gradual resolution of neurological deficits, (balance, circling, nystagmus).
    In many cases the neurological deficits are irreversible but compensation occurs for the vestibular deficits.
  • Resolution of signs of otitis media.

Subsequent Management

Monitoring

  • Neurological re-examination.

Outcomes

Prognosis

  • Good in straightforward cases of otitis interna/labyrinthitis. Damage to delicate nerve endings is likely to be irreparable but disease is rarely bilateral, so some degree of compensation occurs; however, facial paralysis is usually irreversible.

Expected Response to Treatment

  • Neurological signs resolve over a long time period (months).
  • Head tilt may be permanent.

Reasons for Treatment Failure

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Trevor P B & Martin R A (1993) Tympanic bulla osteotomy for treatment of middle-ear disease in cats - 19 cases (1984-1991). JAVMA 202 (1), 123-128 PubMed.
  • Boothe H W Jr. (1988) Surgical management of otitis media and otitis interna. Vet Clin North Am Small Anim Pract 18 (4), 901-911 PubMed.
  • Schunk K L (1988) Disorders of the vestibular system. Vet Clin North Am Small Anim Pract 18 (3), 641-665 PubMed.
  • Shell L G (1988) Otitis media and otitis interna - etiology, diagnosis, and medical management. Vet clin North Am Small Anim Pract 18 (4), 885-899 PubMed.

Other Sources of Information