- What is AA Amyloidosis?
- What does it look like (under the microscope)?
- How did I get it?
- What are the symptoms?
- What is the treatment?
- What is the prognosis?
What is AA Amyloidosis?
AA amyloidosis is a disorder in which a specific type of protein is abnormally deposited into different organs, causing damage.
There are several different kinds of amyloidosis, and the kidneys are the most common organs affected. AA amyloidosis is a specific type of amyloidosis, and is also called secondary amyloidosis. It is a rare disease, affecting approximately 3,000 people in the United States. AL amyloidosis, or primary amyloidosis, is more common than AA amyloidosis. Other types include dialysis-related, senile and heritable amyloidosis.
What does it look like (under the microscope)?
Amyloidosis was originally named to describe the waxy deposits that can be seen under the microscope in kidneys affected by amyloidosis. These deposits are fibrils made up of protein which can be seen in different parts of the kidney, including the glomeruli, the tubules and the arteries of the kidney. The glomeruli are the filters of the kidney through which blood flows and is “cleaned.” This makes the urine which then flows through the tubules where the content of the urine is further refined based on your body’s needs. The arteries are located near both the glomeruli and tubules and carry blood to the different parts of the kidney. The amyloid fibrils can be seen in all these parts of the kidney, and in advanced disease, can form nodules, or clumps of fibrils.
A special kind of stain, called Congo Red, can be used to stain these waxy deposits. It turns them a distinctive apple green color when looked at under polarized light of a microscope. This helps to confirm the diagnosis. The deposits can also be seen under a special type of microscope, called an electron microscope, which can show non-branching fibrils.
How did I get it?
This type of amyloidosis happens in people with some type of chronic inflammatory condition; most commonly, rheumatoid arthritis, both adult and juvenile forms. Other diseases it has complicated include ankylosing spondylitis, psoriatic arthritis, mediterranean fever, Crohn’s, chronic infections and neoplasms (particularly renal cell carcinoma and Hodgkin’s Disease).
Amyloidosis more commonly occurs in people whose underlying disease condition is poorly controlled and longstanding. The condition stimulates the liver to produce a protein, called serum amyloid-associated protein A. Cells of our body’s immune system take this protein up and chew it up into smaller pieces called AA protein which are then deposited in tissues, causing Amyloidosis.
What are the symptoms?
AA amyloidosis can affect different organs, including kidneys, liver, spleen, GI and less commonly the heart. It can affect basically any organ in the body. The symptoms depend on the organs in which it involves in the individual.
Kidney involvement often leads to nephrotic syndrome, which means protein is lost in the urine, swelling in the arms and legs and low levels of albumin.
Liver involvement can cause a large liver, and elevated pressures in the liver which can lead to fluid in the abdomen and swelling of veins in the abdomen which can then burst and bleed.
Heart involvement can lead to heart failure, which can cause shortness of breath and fatigue.
Involvement of peripheral nerves leads to numbness and tingling in the fingers and toes.
What is the treatment?
Treatment for AA amyloidosis is primarily at treatment of the underlying disease and stabilization of affected organs. Aggressive treatment of chronic infections can help stop or slow progression of the disease. Unfortunately, the diagnosis is often made after significant damage has already happened to the organs.
Mediterranean fever is one of the diseases that can predispose a patient to develop AA amyloidosis. In the case of a patient who has developed AA amyloidosis due to Mediterranean fever, colchicine can sometimes be used to treat these patients.
What is the prognosis?
Prognosis in AA amyloidosis depends on successful treatment of the underlying disorder. Rarely, the amyloid deposits will spontaneously go away without this treatment.
