Canis ISSN: 2398-2942

Otitis media

Synonym(s): Middle ear disease

Contributor(s): Kyle Braund, Rosanna Marsella

Introduction

  • Cause: sequel to chronic otitis externa Skin: otitis externa , ascending syndrome through the Eustachian tube.
  • Signs: vestibular syndrome Vestibulocochlear neuritides variable depending on stage and route of infection, eg:
    • Ascending otitis media shows as lethargy, inappetence, fever, slow head-shaking transient head tilt to affected side; signs of otitis externa, ie head-shaking, scratching, pain on palpation of external canal.
  • Diagnosis: signs, radiography or other imaging.
  • Treatment: antibiotics, ear flushing, bulla osteotomy if not responding.
  • Prognosis: may → otitis interna Otitis interna.
    Print off the owner factsheet on Chronic otitis Chronic otitis to give to your client.Follow the diagnostic tree for Evaluating and Managing Otitis Externa/Media Diagnostic tree: Evaluating and Managing Otitis Externa/Media.

Pathogenesis

Etiology

  • Descending infection (more common) following prolonged otitis externa Skin: otitis externa or ascending infection upper respiratory tract infection via Eustachian tube.

Predisposing factors

General

Specific

Pathophysiology

  • Descending: otitis externa → debris accumulation in contact with eardrum → eardrum weakened by infection and ruptures or penetrated by migrating grass seed → medial extension of inflammatory process → hyperemia and thickening of mucoperiosteal lining → accumulation of exudate in tympanic bulla → thickening/sclerosis of bulla → medial spread to cause otitis interna or, rarely, bulla osteomyelitis with involvement of the temporomandibular joint.
  • Ascending otitis media: upper respiratory tract infection → inflammatory spread up Eustachian tube to middle ear → hyperemia and thickening of mucoperiosteal lining → accumulation of exudate → rupture of eardrum in presence of infection → ascending otitis externa and/or medial spread to cause otitis interna → (rarely) bulla osteomyelitis with involvement of temporomandibular joint.
  • Can be associated with nasopharyngeal polyps.

Timecourse

  • >80% of dogs with chronic/recurrent otitis externa Skin: otitis externa develop otitis media Otitis media.
  • ?frequently undetected until severe.
  • Usually sequel to long-term otitis externa (weeks/months).

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Garosi L S, Dennis R, Penderis J, Lamb C R, Targett M P, Cappello R & Delauche A J (2001) Results of magnetic resonance imaging in dogs with vestibular disorders - 85 cases (1996-1999). JAVMA 218 (3), 385-391 PubMed.
  • Allgoewer I, Lucas S & Schmitz S A (2000) Magnetic resonance imaging of the normal and diseased feline middle ear. Vet Rad Ultra 41 (5), 413-418 PubMed.
  • Dvir E, Kirberger R M & Terblanche A G (2000) Magnetic resonance imaging of otitis media in a dog. Vet Rad Ultra 41 (1), 46-49 PubMed.
  • Garosi L S, Lamb C R & Targett M P (2000) MRI findings in a dog with otitis media and suspected otitis interna. Vet Rec 146 (17), 501-502 PubMed.
  • McKeever P J, Torres S M (1997) Ear disease and its management. Vet Clin North Am Small Anim Pract 27 (6), 1523-1536 PubMed.

Other sources of information

  • Rosychuk R A Wet al(2000)diseases of the ear.In:Textbook of Veterinary Internal Medicine.5th edn. Eds: S J Ettinger & E C Feldman. Philadelphia: W B Saunders. pp 986-1002.


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