What are Protein Deposits?
There are two main types of amyloids. AA amyloids usually develop in response to disease and can be found in major organs. They most commonly affect the kidneys, but can also form in the heart, spleen, liver, lungs and brain. Amyloids in the brain may lead to dementia. The second type, AL amyloids, usually develop throughout the body in joints and nerve tissue. Both types of amyloid development are part of a degenerative problem. Early treatment from a veterinarian can greatly extend an affected cat’s life.
After dealing with disease or defect for a long period of time, the body may start to produce abnormally folded protein deposits. This process is referred to as amyloidosis, and the deposits themselves have been termed “amyloids”. These deposits can occur throughout the body, or may remain in one location. The amyloids displace normal cells. This condition can develop in all mammals, but it is generally rare in cats. It is seen more often in older cats than younger cats.
Symptoms of Protein Deposits in Cats
As amyloids most often form in the kidneys, many symptoms are related to kidney failure. If the amyloids have formed in other organs, symptoms will relate to the failing of that organ.
- Polyuria (frequent urination)
- Polydipsia (increased thirst)
- Decreased appetite
- Weight loss
- Swollen limbs
- Mouth ulcers
- Fluid retention
- Breathing problems
- High blood pressure
Causes of Protein Deposits in Cats
While protein deposits are often seen in relation to certain diseases, the exact cause of their formation is unknown. Certain cat breeds are very vulnerable to amyloidosis. Related conditions and risk factors include:
- Hereditary disposition (as seen in Abyssinian and Siamese cat breeds)
- Bacterial infection
- Fungal infection
- Chronic inflammation
- Immune disorders
Diagnosis of Protein Deposits in Cats
If protein deposits are suspected, your veterinarian will require the cat’s full medical history. A complete physical exam will be performed. Full blood work will be needed including a complete blood count and a biochemical profile. This may lead to a discovery of the underlying cause of amyloidosis, such as cancer. Urinalysis will be needed, especially in the case of kidney failure. The urine will be collected over 24 hours to measure how much protein is spilling into it.
X-rays or ultrasounds will be used to evaluate the condition of major organs. If signs of kidney failure are present but both kidneys are of normal size, amyloidosis may be pinpointed. Biopsy is needed for complete diagnosis. Tissue of the affected organ will be collected and tested with the staining of a dye. This will show if any amyloids are present.
Treatment of Protein Deposits in Cats
Amyloidosis itself is not curable. The best treatment would be to identify and alleviate the underlying cause that is creating the protein deposits. Amyloid progression can be slowed, but success depends on how progressed the condition has become.
Certain drugs such as D-penicillamine, thymosin, and even some chemotherapy agents may be prescribed to slow the degeneration caused by amyloidosis. The earlier the condition is caught, the greater the chance that medication will help the cat.
The vet may prescribe a specific and restrictive diet to reduce progression of amyloid formation. If the kidneys have been affected, the diet will be low in phosphorus and protein. If hypertension is present, the diet will have reduced salt.
If there is organ failure in the cat, supportive care will be needed to keep it comfortable and to offer the best possibility of recovery. Generally, this will include fluid administration through IV. Oxygen may also be supplemented.
If the underlying cause is infection, antibiotics or antifungal medication can greatly help the overall health of the cat.
Recovery of Protein Deposits in Cats
After the cat has been discharged from the veterinary clinic or hospital, it will need weekly check-ups to monitor weight gain and collect blood and urine for status testing. If you own a susceptible cat breed, it is important to have an annual exam to screen for amyloidosis. Once the cat becomes a senior, testing should be done twice annually. If caught in its earliest stages, amyloidosis can be slowed down.
If organ damage has occurred, it is not reversible. Certain underlying causes can not be cured. If amyloidosis has progressed for a long period of time, prognosis is guarded. In the case of kidney amyloids, survival is often only 3-20 months. If organs have not been affected, and the amyloids are discovered early, the cat may live a normal life span.