Hepatic Lipidosis

Signalment

Indoor cat more prone to primary hepatic lipidosis

Description

Hepatic lipidosis is the derangement of lipid and protein metabolism, which occurs cats and dogs, but more clinically significant in cats. It is important to differentiate primary (idiopathic) hepatic lipidosis from secondary hepatic lipidosis.

Primary hepatic lipidosis is most recognised in obese indoor cats following anorexia in North America. The mortality rate is high unless the disease is treated aggressively. The pathogenesis includes a number of factors:

• Excessive lipid mobilisation which is induced by anorexia, illness or stress.
• Deficiency of dietary proteins and other nutrients, which reduces the liver's capacity to produce transport proteins and to metabolise fat. Recognised nutrient deficiencies include arginine, carnitine, taurine and methionine.
• Disturbances in the neurohormonal control of appetite resulting in inappropriate anorexia.

Secondary hepatic lipidosis is a common response in dogs and cats to other diseases for example, pacreatitis, diabetes mellitus, inflammatory bowel disease and primary hyperlipidaemia. The effect on dogs is less clinically significant. Aggressive intervention of the hepatic lipidosis and the underlying cause is required.

Up to 50% of cats have an underlying disease which leads to anorexia. If treated aggressively, it is often a reversible process.

Factors which contribute to hepatic lipidosis are:

• Cholangitis/Cholangiohepatitis
• Obesity
• Starvation
• Pancreatitis
• Diabetes

Diagnosis

Clinical Signs

• Often obese cats following a sudden starvation
• Anorexia and lethargy
• Jaundice
• Hepatic Encephalopathy
• Diarrhoea (sometimes)
• Palpable hepatomegaly (sometimes)
• Coagulopathies (sometimes)

Laboratory Tests

Biochemistry

• Markedly increased level in alanine
• Low gamma-glutamyltransferase (GGT) concentration

Diagnostic Imaging

Abdominal radiography shows a marked hepatomegaly. On ultrasound, an enlarged and diffusely hyperechoeic liver is seen.

Histopathology

Fine needle aspirate of the liver is normally sufficient for a diagnosis. Cytology demonstrates hepatocytes swollen with lipid. Biopsy and culture of the liver tissue is always indicated to determine the underlying cause of the disease.

Treatment

• Nutritional support for 4 - 6 weeks
  • This is the most important treatment in hepatic lipidosis. It is vital to ensure that the diet is of adequate calorific content with an increase in protein content. Specific nutrients such as arginine, taurine, or carnitine may also be added.
  • This can be done via different feeding systems such as naso-oesophageal tube, oesophagostomy tube, gastrostomy tube.
• Treat for Hepatic Encephalopathy if presented.

References

• Ettinger, S.J. and Feldman, E. C. (2000) Textbook of Veterinary Internal Medicine Diseases of the Dog and Cat Volume 2 (Fifth Edition) W.B. Saunders Company.
• Nelson, R.W. and Couto, C.G. (2009) Small Animal Internal Medicine (Fourth Edition) Mosby Elsevier.