Diagnosis of primary secretory otitis media in the cavalier King Charles spaniel

Primary secretory otitis media (PSOM) is a disease reported in the cavalier King Charles spaniel (CKCS). The diagnosis of PSOM has been made based only on visualization of a bulging tympanic membrane and mucus in the middle ear post-myringotomy. No additional tests have been evaluated for the diagnosis of PSOM; CKCSs with early disease may have been missed.

The objective of this study was to compare otoscopy, tympanometry, pneumotoscopy and tympanic bulla ultrasonography, using computed tomography (CT) as the gold standard for the diagnosis of PSOM in the CKCS.

Sixty CKCSs with clinical signs suggestive of PSOM.

Otoscopy, CT scan, tympanic bulla ultrasonography, tympanometry and pneumotoscopy were performed; those CKCSs with a soft tissue density in the middle ear identified on CT had a myringotomy and middle ear flush.

Forty-three (72%) CKCSs had PSOM (30 bilateral, 13 unilateral). A large bulging pars flaccida was identified in only those CKCS with PSOM (specificity of 100%); however, only 21 of 73 ears with PSOM had a large bulging pars flaccida (sensitivity of 29%). Sensitivity and specificity for tympanometry, pneumotoscopy and tympanic bulla ultrasonography were (84%, 47%), (75%, 79%) and (67%, 47%), respectively.

Based on these results a large bulging pars flaccida indicates the presence of PSOM, whereas a flat pars flaccida may be present in CKCS that have PSOM as well as those that do not. In CKCSs with a flat pars flaccida none of the above diagnostic tests can be recommended in place of CT scan for the diagnosis of PSOM.