Multifactorial headshaking in a sport horse with otitis media, infraorbital canal malposition and dental malocclusion

Summary An 8‐year‐old Warmblood gelding was referred for investigation of owner‐reported progressive headshaking, head tossing, girth aversion and exercise‐associated coughing. Previous orthopaedic assessment and cervical radiography had revealed no clinically relevant abnormalities. Clinical examination identified a right‐sided head tilt, mild right‐sided hemifacial asymmetry, including ear drooping and nostril asymmetry, right‐sided auditory loss and marked right‐sided dental malocclusion. Headshaking was not observed during the clinical examination. Otoscopy revealed no abnormalities of the external ear canal. Respiratory endoscopy and cytology demonstrated mild lower airway inflammation, and endoscopic examination of the guttural pouches was unremarkable. Gastroscopy revealed moderate glandular ulceration. Due to persistent owner‐reported headshaking and asymmetric neurological signs, standing computed tomography (CT) of the head and craniocervical region was performed. Imaging revealed soft‐tissue‐to‐fluid‐attenuating material within the right tympanic bulla, consistent with otitis media. Additional findings included ventral malposition of the right infraorbital canal in close proximity to the apices of maxillary cheek teeth 110 and 111, severe unilateral right dental malocclusion with markedly reduced occlusal contact, pronounced thickening of the rostral nasal septum, and an atlanto‐occipital osteochondral fragment of uncertain clinical relevance. Unilateral otitis media was considered a likely contributor to auditory loss and abnormal head carriage, while dental malocclusion and infraorbital canal malposition were considered possible additional contributors to discomfort and head‐shaking behaviour. Given the prolonged clinical history and the extent of the structural changes, the prognosis for return to athletic function was poor, and euthanasia was elected. This case illustrates the multifactorial nature of equine headshaking and the complementary value of CT for identifying structural abnormalities when clinical, otoscopic and conventional diagnostic investigations are inconclusive.