Case Study

CT – Chronic otitis media with inflammation and reactive lymphadenitis in an Irish Setter dog

This Irish Setter dog presented with a history of chronic otitis

DX

The computed tomographic findings are compatible with severe right-sided chronic Otitis media et externa with surrounding soft tissue inflammation and reactive lymphadenitis. Involvement of the peripheral branches of the (vestibulo)cochlear and facial nerve is suspected.

Image Interpretation

CT of the head, plain and post contrast – The right tympanic bulla is entirely filled with soft tissue attenuating material, which
does not show increased contrast enhancement. Similar material fills the medial aspect
of the horizontal external ear canal. The wall of the external ear canal reveals moderate
generalized thickening with increased contrast enhancement. The wall of the right
tympanic bulla presents moderate, generalized, bony thickening and the bone is
porous. The inflammation extends into the surrounding soft tissue, which reveals
diffuse mild thickening, and increased contrast enhancement, New bone formation is
noted at the emergence of the right external ear canal.
The inner ear does not reveal structural abnormality, yet the inflammation involves the
exit zones of the (vestibulo)cochlear and facial nerve.
The left tympanic bulla is within normal limits. A mild amount of soft tissue
attenuating, non-enhancing material is noted within the medial aspect of the left
horizontal external ear canal. The ear canal wall reveals mild thickening and mild
increase of contrast enhancement.
No intracranial extension or other intracranial abnormality is noted.
Mild reactive adenitis of the right medial retropharyngeal, parotid and mandibular
lymph nodes is noted.

Outcome

No intracranial extension or other intracranial abnormality is noted.
There is mild chronic left-sided Otitis externa.
Bilateral otoscopic evaluation is advisable but likely has been performed yet.
The severity and chronicity of the findings on the right side are likely to render this a
surgical candidate for bulla osteotomy especially when this is supported by lacking
response to conservative management.
Culture of the microorganisms is mandatory in any case to induce/maintain the
antimicrobial treatment appropriately.