Arterial malformations leading to bilateral spontaneous renal hemorrhage in a dog

To describe the clinical presentation, diagnostic imaging, management, and follow-up of a dog that presented with sequential, bilateral, spontaneous, subcapsular and perirenal hemorrhage (Wunderlich syndrome) due to bilateral renal arterial malformations.

A 9-year-old intact male Field Spaniel presented for acute onset abdominal pain following a possible syncopal episode. Abdominal ultrasonography, contrast-enhanced ultrasound, and computed tomography (CT) revealed right-sided perirenal hemorrhage that extended into the peritoneum. The dog was discharged following stabilization with analgesia, fluid therapy, and tranexamic acid. One month later, the patient presented with identical clinical signs. A CT scan at this stage revealed bilateral kidney infarcts with new left-sided perirenal hemorrhage. Abdominal ultrasound and contrast-enhanced ultrasound were repeated and showed similar findings. Follow up with four-dimensional CT angiography revealed bilateral renal arterial malformations, likely causing spontaneous renal hemorrhage and secondary subcapsular hematomas , retroperitoneal and peritoneal hemorrhage.

This is the first reported case of both bilateral renal arterial malformations and bilateral spontaneous subcapsular and perirenal hemorrhage in the absence of neoplasia, coagulopathy, or trauma in a dog. Advanced imaging modalities, including selective angiography, were required to diagnose this condition successfully. Arterial malformations should be considered as a differential diagnosis in cases of hemoretroperitoneum. Nephrectomy due to perirenal hemorrhage should be cautiously considered, especially in the absence of angiography, because of the sequential bilateral nature of this case. Conservative management in this case resulted in a good long-term outcome 10 months later.