Hypervitaminosis A & Chronic Hepatic Injury

An 8-year-old neutered domestic shorthaired cat presented for tetraparalysis 12 hours after a fall. The cat had been experiencing difficulty in ambulation for 3 months prior, was indoor only, and was exclusively fed a home-made diet based on raw beef liver and giblets.

Physical examination confirmed tetraparalysis; no reflexes or deep pain sensation were present in the limbs, and there was osseous crepitation with severe pain evident on manipulation of the cervical and thoracic spine. Radiographic evaluation of the cervical and thoracic vertebrae revealed exostosis and fusion of all vertebrae from C1-T7, with fracture and deviation of the spinal axis at the level of C1 and C2. The animal was euthanized and gross pathology confirmed radiographic findings. High levels of vitamin A in the liver were measured, and histopathology revealed severe hepatic fibrosis and stellate cell lipidosis. Liver injury in cases of vitamin A toxicity is likely caused by excessive accumulation of vitamin A in the liver, leading to fatty accumulation and liposomal storage disease. Although the exact mechanism of injury in cats is unknown, these changes ultimately can lead to varying degrees of fibrosis and, ultimately, cirrhosis.

This report is the first to show that hypervitaminosis A can lead to chronic hepatic injury in the cat, which in turn can lead to fibrosis and, ultimately, cirrhosis. Although the cat in this report died secondary to osteopathology, hepatic metabolic storage disease would likely have contributed to its overall health. Cases like this are extreme examples of the importance of balancing a home-cooked diet. Although major metabolic complications of nutritional imbalance are rare, it is important to emphasize that not all foods provide bioavailable nutrients in the dog or cat; each species has unique metabolic or dietary needs. A veterinary nutritionist is the best resource for the practitioner and client to formulate home-made diets that are balanced and safe.—Heather Troyer, DVM, DABVP, CVA

Hypervitaminosis A-induced hepatic fibrosis in a cat. Guerra JM, Daniel AGT, Aloia TP, et al. J FELINE MED SURG 16:243-248, 2014.