Background

To describe the clinical presentation, diagnosis, management and outcome of a dog with oculocardiac reflex secondary to acute ocular trauma.

Case Presentation

A 6-year-old, spayed Belgian Malinois, presented to the emergency unit with facial trauma following a motor vehicle accident. Upon arrival, the dog was ambulatory, quiet and responsive. The left eye exhibited mild exophthalmos, hyphema, and sub-conjunctival bleeding and swelling. Bradycardia (heart rate [HR] of 60 bpm) and systemic hypertension, observed upon presentation, and corroborated in several consecutive measurements, remained unchanged following intravenous crystalloid and later mannitol infusions. Analgesia with methadone resulted in normalization of systemic hypertension, in face of persistent bradycardia, ultimately reaching a nadir of 32 bpm. A CT scan of the head showed no evidence of brain injury or intracranial hemorrhage. The left globe was poorly marginated, and there was a large retro-bulbar soft tissue swelling associated with the orbital space. Electrocardiogram revealed a second-degree, Mobitz I, atrioventricular block. An atropine trial (0.04 mg/kg, IV) resulted in HR acceleration (150 bpm) with normal sinus rhythm, and thus a diagnosis of oculocardiac reflex was made. Subsequently, a trans-palpebral enucleation of the ruptured globe was performed to relieve intra-orbital pressure and extraocular muscle tension, producing a persistent rise in HR above 80 bpm.

New/Unique Information

To our knowledge, this is the first description of an oculocardiac reflex due to acute ocular blunt trauma in companion animals. We suggest an additional differential diagnosis for animals presenting with bradycardia following head trauma.

E-mail: miki.hatzav@mail.huji.ac.il