Temporohyoid osteoarthropathy in a mare with unilateral facial paralysis and vestibular signs

Abstract

The aim of this case report was to present clinical signs and radiographic features of one of the most important peripheral vestibular diseases in horse, and also present the treatment for this disease. Temporohyoid osteoarthropathy (THO) is caused by proliferation of the proximal stylohyoid bone and petrous temporal bone which finally results in ankylosis of the temporohyoid joint. Any sudden movement may result in damage to the joint and also structures in its vicinity. Some peripheral nerves especially cranial nerve VII and VIII may be affected and THO manifestation appears. The mare presented in this report was referred with unilateral facial nerve paralysis, ptosis and vestibular signs including ataxia, head tilt and circling. X-ray was used to confirm the diagnosis. By X-ray, the left stylohyoid bone showed osteoarthropathy, which confirmed the diagnosis. Treatment consisted of fluid therapy, dexamethasone (0.2 mg/kg every 24 hours IV for 10 days), and antibiotic administration (24 mg/kg potentiated sulfonamide every 24 hours IM for 30 days). The vestibular signs disappeared after 3 months. However, one year after the treatment, the facial nerve paralysis still remained.