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Amyloidosis in Cats

Reviewed by Dr. Celeste Clements, DVM, DACVIM on Thursday, September 3, 2015
Posted September 04, 2015 in Cat Diseases & Conditions A-Z

Cat looking away

What is amyloidosis?
When cellular proteins form into folded sheets, instead of their correct three-dimensional shapes, amyloidosis occurs. This abnormal protein cannot be dissolved (insoluble) and it is resistant to normal digestion and breakdown. When deposited into different tissues/organs in the body, it is called amyloid1; it causes damage to, and displacement of, the normal cells. Minor, asymptomatic deposits of amyloid can occur with age. But extensive amyloidosis can cause significant and sometimes fatal disease1.

What causes amyloidosis in cats?
Usually, amyloid originates from a protein that is formed in response to inflammation. Any condition that causes severe inflammation can trigger the deposition of the abnormal proteins, including1:

This spontaneous development of amyloidosis is a relatively unusual disorder in cats in general; however, it does occur as a genetic disorder in Abyssinian, Siamese and Oriental shorthair breeds, says DVM360.

Signs that your cat has amyloidosis
Remember that the amyloid deposits can occur in any location in the body–sometimes locally, in just one place, and sometimes more systemically. In small amounts, no damage occurs and no disease is apparent. It is only when the deposits interfere with normal organ function that clinical symptoms appear, and then they are related to the failure of the specific affected organ system2:

  • Liver disease with liver amyloidosis
  • Kidney disease with renal amyloidosis

Diagnosing amyloidosis in cats
Your veterinarian will first diagnose your cat with a tissue specific disease or disorder and will then have to determine that the problem is the result of amyloidosis, which can be very difficult.

According to DVM360, affected Siamese and Oriental shorthair cats that deposit amyloid in their livers sometimes present with acute, internal, abdominal bleeding due to rupture of the lesions. Abyssinian cats with the disease can present at a very young age (typically between 1 and 5 years) with rapidly progressive kidney failure. Other cats that are only mildly affected can live long lives with no discernible, related illness.

The only way to definitively diagnosis the presence of amyloidosis is to obtain biopsy samples of the affected tissues for microscopic review with special stains.

Related symptoms: 

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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.