Abstract

Hemochromatosis has been described in veterinary and human medicine, and is considered uncommon in pinnipeds aside from reports in northern fur seals.^1,2,3,4,5 Information regarding normal serum ferritin, transferrin saturation (TSAT) levels, and criteria to determine when to initiate therapy for treatment of iron overload in pinnipeds is lacking.

Here we present the diagnosis, treatment criteria, and management of a 21-year-old castrated male California sea lion (Zalophus californianus, CSL) with severely elevated gamma-glutamyl transferase (GGT), intermittent anorexia, and abdominal discomfort. Abdominal MRI and liver biopsy confirmed hepatocellular hemosiderosis, in addition to elevated serum ferritin and transferrin saturation levels (TSAT). Diet modifications to increase the diversity of native fish types and decrease the oral iron uptake were attempted, but significant decreases in serum iron, ferritin, and TSAT were not achieved (p<0.05).⁷ Serial phlebotomies were initiated, first under general anesthesia, and subsequently under voluntary control utilizing the superficial palmar vein. The volume of blood collected during each phlebotomy was calculated based on the estimated total blood volume (approx. 1 liter)⁸, and total amount of iron removed was quantified based on the blood hemoglobin concentration, (0.6–1 gram)⁹. Serum ferritin, TSAT, and GGT decreased over time as more iron was removed, however the serum iron remained static. To the best of our knowledge, this is the first documented management of hemochromatosis in a CSL.

Acknowledgements

The authors would like to sincerely thank Dr. Marina Ivančić, Dr. Robert M. Marks, and Dr. Benjamin Drinkwine (Radiologists from NMCSD), for help with the multiple diagnostics involved in this case. Veterinary technicians Jammy Eichman, Anthony Perron, and Ashley Survillion who work tirelessly on each phlebotomy. All of the other veterinarians and technicians of the National Marine Mammal Foundation and U.S. Navy Marine Mammal Program who continue to help provide the best possible care for our animals.

Literature Cited

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