Bilirubin is a yellow waste byproduct formed by breakdown of red blood cells. Bilirubin is processed by the liver and excreted into the bile. If red blood cells are being broken down rapidly, or if the liver fails to process bilirubin properly, excess bilirubin in the bloodstream accumulates in the skin, resulting in jaundice.
Jaundice is often difficult to spot in a cat because of their fur, and is particularly difficult to identify in cats with darkly pigmented skin. It is most noticeable in a cat’s gums, their sclera (the white part of their eyes), and the pinnae (ear flaps).
Jaundice is caused by a variety of different conditions, but is always cause for medical concern. A cat with jaundice requires prompt medical attention, even if they show no other symptoms. Cats showing symptoms such as pale gums, collapse, weakness, or extreme lethargy require immediate medical attention.
Conditions resulting in icterus either cause liver disease or red blood cell destruction.
The degree of jaundice directly depends on the level of bilirubin that accumulates in the tissue, and is not necessarily reflective of the severity or prognosis of the underlying condition. Any jaundice-causing condition can cause mild, moderate, or severe jaundice, depending on the degree of bilirubin accumulation occurring. Generally, conditions that result in more severe bilirubin accumulation, such as bile duct obstructions, cause more severe yellowing of the tissue, although they have a favorable prognosis. Cats that are predisposed to liver disease or conditions causing destruction of red blood cells are at higher risk of developing jaundice.
Diagnosis of the underlying condition causing jaundice usually requires a combination of:
General treatment approaches typically involve medication and nutraceutical supplements to support liver function. Ensuring cats have adequate hydration through IV fluids and adequate nutrient intake through nutritional therapy is also important to resolve symptoms. Specific treatments such as steroids or antibiotics may be needed depending on the underlying cause of disease. Cats with severe RBC destruction often require blood transfusions.
Jaundice is unique and not easily confused with other symptoms. It is different from pale or bleeding gums and bloodshot or cloudy eyes.