Case report of unilateral retrobulbar hematoma associated with von Willebrand disease in a Doberman Pinscher dog.

A 5-year-old Doberman Pinscher dog was presented with sudden onset left-sided periocular bleeding following third eyelid gland replacement surgery. Left-sided exophthalmos and 360-degrees subconjunctival hemorrhage were present. The ophthalmic examination revealed blindness with absent direct and consensual pupillary light reflexes. A superficial exposure ulcerative keratitis due to exophthalmos was also present. Computed tomography (CT) revealed a large left-sided retrobulbar mass lesion surrounding the optic nerve, compatible with a retrobulbar hematoma. Due to absence of orbital fractures and no history of trauma, a coagulopathy was strongly suspected. The buccal mucosal bleeding time (BMBT) was prolonged (>4 minutes) consistent with a primary hemostatic defect in the absence of thrombocytopenia. Von Willebrand factor antigens levels were decreased (24%- Normal Range: 50%-150%). Surgical drainage of the retrobulbar hematoma was performed uneventfully thirty minutes after subcutaneous injection of desmopressine acetate, Minirin® (1 µg/kg, SC). Von Willebrand disease type I gene mutation was confirmed by PCR amplification of the DNA encoding von Willebrand factor. This case report demonstrates that hemostatic disorders, including von Willebrand Disease (vWD), are a risk factor for orbital bleeding following surgical trauma. Retrobulbar hematoma should be considered as a differential diagnosis in any dog with exophthalmos.