Introduction: Pneumolabyrinth is recognized in humans and a dog, as a condition characterized by presence of air within the vestibule of the inner ear, following traumatic injury, perilymphatic fistula or otitis. Pneumolabyrinth is associated with severe vestibular ataxia, and successfully treated with anti-inflammatories and antibiotics, resulting in clinical and radiographic resolution.
Case 1: 8-year-old AQHA mare, presented for acute onset right cranial nerve VII lesions, without vestibular ataxia, underwent standing head CT that identified grade 3 temporohyoid osteoarthropathy (THO). Eight weeks following successful partial ceratohyoidectomy, she re-presented with grade IV/V vestibular ataxia. Repeat head CT revealed progressive otitis media and discrete regions of air accumulated within the vestibule of the inner ear, or pneumolabyrinth, see Figure 1.
Case 2: 4-year-old AQHA mare presented for rapidly progressive vestibular ataxia and right cranial nerve VII deficits underwent a standing head CT. Grade 3 THO was identified, with otitis media and pneumolabyrinth.
Case 3: 17-year-old Haflinger mare presented for a 5-day history of grade IV/V vestibular ataxia and left CN VII signs. Standing head CT revealed grade 3 THO, otitis media and pneumolabyrinth. Management: All cases were treated with a taper-course of oral prednisolone, trimethoprim-sulfamethoxazole, and 4+ weeks of strict stall rest.
In all three cases, vestibular ataxia resolved within 14 days. Case 1 received a follow up head CT at the resolution of vestibular ataxia, confirming resolution of the pneumolabyrinth.
Conclusions: Pneumolabyrinth should be considered in horses with THO presenting with vestibular ataxia, and can resolve with medical management, similar to reports in other species.
