Computed tomographic diagnosis and treatment of pneumolabyrinth in a mare with temporohyoid osteoarthropathy

Summary Pneumolabyrinth, which is the presence of gas within the labyrinth of the inner ear, can be associated with severe peripheral vestibular signs. This report describes a case of pneumolabyrinth in a horse that presented with vestibular ataxia. An 8‐year‐old Quarter Horse mare that presented with cranial nerve VII deficits underwent a standing head computed tomography (SHCT) evaluation. This revealed findings consistent with right grade 3 temporohyoid osteoarthropathy (THO) and right otitis media (OM). A right‐sided partial ceratohyoidectomy was performed. Approximately 1.5 months postsurgery, the patient presented for acute onset of Mayhew's grade 4 ataxia and peripheral vestibular syndrome. A follow‐up SHCT revealed progressive right otitis media and gas (approximately −525 HU) within the vestibule of the inner ear, consistent with pneumolabyrinth. The patient was treated with a tapering course of prednisolone, a trimethoprim/sulfonamide antibiotic, and strict stall rest. A good response was noted, with return to the previous neurologic status, persistence of cranial nerve VII deficits and resolution of all other deficits. A recheck SHCT 3 months later showed resolution of pneumolabyrinth, unchanged right THO, right partial ceratohyoidectomy site and right OM. This is the first case report of pneumolabyrinth in a horse, with concurrent THO and OM, showing complete imaging resolution following medical management and improvement of clinical signs.