A young adult male Northern sea otter (Enhydra lutris kenyoni) presented off the west coast of Vancouver Island, British Columbia, Canada with severe positive buoyancy. The animal was taken to a rehabilitation center in Vancouver, British Columbia, and was found to have multiple rib fractures and severe generalized subcutaneous emphysema. After several weeks of medical care and nutritional support, the animal gained weight and the subcutaneous emphysema resolved. Following a procedure under sedation to investigate a new mass over the area of the fractured rib, significant pigmenturia was noted. Ultrasound revealed right hydronephrosis, suspected to be secondary to renal trauma associated with the fractured rib in the same region, and what appeared to be a large blood clot in the bladder. Bloodwork revealed a decrease in PCV of 4% (37% from 41% within a few hours, normal 40–66%).1 With close monitoring for signs of urinary obstruction and supportive care of non-steroidal anti-inflammatories and a benzodiazepine, pigmenturia resolved with the passage of multiple small blood clots over three days.
The animal was sedated one week later in an attempt to remove a portion of the fractured rib, during which blood was sampled and the PCV was 15% and the blood urea nitrogen had increased to 82.6 mg/dL from 16.1 mg/dL (31–90 mg/dL).1 No pigmenturia was noted, however, and the animal recovered from the procedure while possible need for a transfusion was considered. Three days later, approximately 20 mL of frank blood, suspected to be from the urinary tract, was found under the animal. He was lethargic, hyporexic, and vocalizing. Due to concern regarding progressive anemia, azotemia, and the potential for urethral obstruction, an exploratory laparotomy with a potential right nephrectomy was elected. Blood was collected from an unreleasable, healthy adult male E. lutris under human care, and macro- and micro-agglutination were performed to confirm a feasible match between donor and recipient. Intra-operatively, a cystotomy was performed to remove a large blood clot, and a urinary catheter was passed retrograde to assure patency. The right kidney was removed with a mild amount of hemorrhage, and the blood transfusion was given after anesthetic complications, including sinus arrest, occurred. There were no apparent adverse effects from the transfusion.
Post-operatively, the animal was not mentally appropriate and experienced severe electrolyte abnormalities, urinary retention, and severe azotemia. Respiratory and cardiac arrest occurred 24 hours post-operatively with unsuccessful resuscitation. Pathologic findings included marked pyogranulomatous pyelonephritis with multifocal intralesional mineral deposits and myriad Langhans-type multinucleated giant cells, nodular to diffuse hepatocellular coagulative necrosis, massive focally extensive acute pulmonary hemorrhage, chronic granulomatous to xanthogranulomatous peritonitis with microabscessation, and severe uroabdomen. To the authors' knowledge, this is the first nephrectomy performed in a marine mammal and one of the first blood transfusions recorded in sea otters.
The authors would like to thank the staff and volunteers at the Vancouver Aquarium Marine Mammal Rescue Centre for their incredible effort in caring for this otter (especially Emily Johnson, Sion Cahoon, Chelsea DeColle, Jenelle Hebert, Andrew Celmainas, Kit Thornton, Belinda To, Teresa Budge, and Talia Smith), as well as the marine mammal care team and Elfin the sea otter at the Vancouver Aquarium Marine Science Centre for their help with the blood donation.
* Presenting author
+ Student presenter
1. Bossart GD, Reidarson TH, Dierauf LA, Duffield DA. Clinical pathology. In: Dierauf LA, Gulland FMD, eds. CRC Handbook of Marine Mammal Medicine. 2nd ed. Boca Raton, FL: CRC Press LLC; 2001:383–436.