Abdominal ultrasound typically reveals liver enlargement (ie, hepatomegaly) with diffuse hyperechoic parenchyma, hyperechoic falciform fat and renal cortices, and an isoechoic spleen. Additional findings may include pancreatitis, triaditis (ie, concurrent cholangitis, pancreatitis, inflammatory bowel disease), biliary disease, and thickening of the small intestinal tract, which may indicate inflammatory bowel disease vs lymphoma.
Thoracic radiography is indicated in older patients or if cardiopulmonary disease is suspected. If a neoplastic process is suspected, 3-view chest films should be obtained.
A coagulation profile, specifically evaluation of prothrombin time and partial thromboplastin time, is an important part of the diagnostic evaluation. Cats can become vitamin K-deficient in <7 days (see Suggested Reading), and, in the author’s experience, >50% of cats with hepatic lipidosis have coagulation abnormalities. Coagulopathic patients may be at increased risk for hemorrhage after invasive diagnostic procedures (eg, aspiration, biopsy). Jugular venipuncture or central line placement also may lead to hemorrhage.
Without cytology, the disease may be suspected but cannot be confirmed. Hepatocellular lipid vacuolation is typically dramatic and diagnostic in feline hepatic lipidosis cases. The author more aggressively recommends this diagnostic approach in older patients to help differentiate ultrasound changes that may also be consistent with lymphoma, as well as for patients in which the history is inconsistent with hepatic lipidosis. Histopathology is rarely used but may be obtained for patients undergoing surgery for an unrelated reason (eg, foreign body, neoplasia).