Cat with lethargy and anorexia

History of Present Illness

An 8-year-old, female, spayed American domestic shorthair cat is brought to the clinic by her owner for further evaluation. One week prior, the owner found the cat hiding and observed that the cat was not well; she appeared lethargic and not interested in food, and her skin and mucus membranes appeared yellow. She was taken to the referring veterinarian's clinic, and laboratory studies showed anemia and increased serum liver enzymes. She was treated with IV fluids, broad-spectrum antibiotics, a blood transfusion, and steroids for 4 days. The patient improved somewhat and was discharged. At home the patient relapsed and was referred for further evaluation.