[Unilateral facial paralysis and keratitis sicca, signs of temporohyoid osteoarthropathy in the horse].

This study presents a case of a 9-year-old Dutch Warmblood mare that developed facial nerve paralysis and dry eye syndrome, conditions which were attributed to an inflammatory joint disease, known as temporo-hyoid osteoarthropathy.

Case Overview

• A 9-year-old Dutch Warmblood mare showed unusual behavior and had acquired acute facial nerve paralysis on the left side. She also had a slightly tilted head and a corneal ulcer in the left eye, and the base of the left ear was warm and painful.

Diagnosis and Findings

• An endoscopic examination of the left guttural pouch revealed a thicker proximal part of the stylohyoid bone, which is a bone connected to the hyoid apparatus in the throat and the temporal bone at the base of the skull.
• A Computer Tomography (CT) scan showed a left-sided prominent bony enlargement of the middle and proximal part of the stylohyoid bone and the tympanic bulla, which is a part of the middle ear. The temporo-hyoid joint, a joint connecting the tympanic bulla and the stylohyoid bone, showed fusion and there was bone proliferation of the pars petrosa part of the temporal bone.
• The post-mortem examination confirmed the diagnosis of temporo-hyoid osteoarthropathy, a joint and bone disease involving the temporo-hyoid joint.

Discussion

• The study discusses the literature concerning the anatomy, clinical signs, and therapy of temporo-hyoid osteoarthropathy.
• Temporo-hyoid osteoarthropathy in horses causes symptoms such as behavioral changes, head tilt, facial nerve paralysis, corneal ulcers, and pain around the ear due to inflammation of the joint and alterations in the related bones.