Case Study

CT- Severe chronic otitis media and externa with bulla wall lysis and osteitis in a 7 year old FS dog

This 7 year old FS dog presented with a history of chronic ear infection

Physical Exam: fluid in left horizontal ear canal

This 7 year old FS dog presented with a history of chronic ear infection

Physical Exam: fluid in left horizontal ear canal

DX

Severe chronic otitis media and externa with osteitis and lysis of the bulla wall on the left - Subacute otitis media on the right - Reactive regional lymphadenitis. Mild non-specific, non-destructive unilateral rhinitis - Non-specific lymphadenopathy of the right superficial cervical lymph node with a reactive pattern

Image Interpretation

CT of the head, plain and post contrast- The horizontal part of the left ear canal is filled with hypoattenuating, non-enhancing
material. The ear canal wall reveals moderate thickening and increased contrast
enhancement.
The left tympanic bulla is filled with hypoattenuating material whichshows peripheral
rim enhancement of the thickened mucosal lining. Only the central portion of the bullar
reveals a residual amount of air. The bony wall of the bulla is poruous and thin. There
is a peripheral inflammatory pattern noted within the surrounding soft tissues. The
bony emergence of the left ear canal at the bulla exit is moderately expanded and thin.
The right tympanic bulla is completely filled with hypoattenuating, non-enhancing
material. The bony bulla wall is even and thin.
There is a mild amount of non-enhancing hypoattenuating associated with the nasal
turbinates within the left nasal cavity.
The left and right submandibular, parotid and medial retropharyngeal lymph nodes
reveal mild generalized enlargement with a benign reactive pattern.
The right superficial cervical lymph node presents moderate enlargement with
preserved short-to-long axis ratio and regular enhancement behaviour.

Outcome

Note that the thinning of the bulla wall has to be anticipated to be more severe than
evident on the images since the point spread effect in CT renders the wall thicker
artificially when it is filled with soft tissue opaque material.
The findings are severe. Surgical therapy by means of left-sided bulla osteotomy is
indicated here.
Full otoscopic examination and otoscopy guided drainage/lavage should be considered
for the right-sided otitis media.
Obtain bacterial culture and support with pertaining systemic antimicrobial treatment.
Consider fine needle aspiration of the right superficial cervical lymph node and rule
out pathology within its tributary region.