The Disease: Amyloidosis
Information from The Cleveland Clinic
What is amyloidosis?
Amyloidosis is a disease in which an abnormal protein (amyloid) builds up in organs and tissues, impairing their function. Amyloid is a protein polysaccharide substance with starch-like characteristics.
What causes amyloidosis?
The cause of amyloidosis is unknown. Amyloidosis is thought to result from many factors.
Is amyloidosis a form of cancer?
No. Amyloidosis is not a form of cancer, although it may occur in some people who have multiple myeloma.
Multiple myeloma is part of a spectrum of diseases called plasma cell dyscrasia. Plasma cells are responsible for forming antibodies against bacteria and foreign proteins. For reasons that are unclear, these cells lose their ability to respond to controlling signals from immune cells. Plasma cells then divide and form abnormal proteins that damage the bone, bone marrow or other organs of the body.
What are the signs and symptoms of amyloidosis?
- Weakness or fatigue
- Weight loss
- Heart damage (congestive heart failure)
- Shortness of breath
- Swelling of the feet and legs (edema)
- Chest pain
- Irregular heart rhythm
- Lightheadedness (due to blood pressure lowering during sudden position changes) in the arms, feet or legs
- Kidney damage (renal failure)
- Swelling of the feet and legs (edema)
- Shortness of breath
- Decreased energy level
- Anemia (low hemoglobin level)
- Skin changes (such as a non-itchy rash, unusual sores or bumps, or thickening of the skin), especially on or near the eyelids, ears and body folds
- Abnormal nail changes
- Unusual hair loss
- Unusual or easy bruising
- Abnormal sensations or numbness in the feet, arms or legs
- Swelling of the lymph glands
- Enlarged tongue (uncommon)
- Symptoms related to damage of the autonomic nervous system (autonomic neuropathy) including bloating or diarrhea -- these symptoms are especially present in the neuropathic hereditary amyloidosis (or "familial" amyloidosis)
- Bone damage and bone fractures (if large amyloid deposits are present)
- Changes in vision (caused by amyloid deposits behind the lens of the eye) may occur in familial amyloidosis
- Sudden drop in blood pressure following changes in posture
Who is affected by amyloidosis?
Amyloidosis is a very rare disease. About two-thirds of patients with amyloidosis have secondary amyloidosis; less than 5% have primary, familial or senile amyloidosis. There are about 2,000 cases diagnosed in the US yearly. In patients with primary amyloidosis, 95% are over the age of 40 and 66% are men.
How is amyloidosis diagnosed?
The diagnosis of amyloidosis is often delayed either because the cause is unclear (as in primary amyloidosis) or the signs and symptoms of the underlying chronic disease mask the signs of amyloid deposits (as in secondary amyloidosis).
Upon physical examination, amyloidosis should be suspected in the presence of any combination of the signs and symptoms listed to the left or when there is:
- Slow onset of unexplained protein in the urine
- Unexplained kidney failure
- Enlarged liver or spleen
- Malabsorption of food
- Nerve damage
- Unexplained congestive heart failure
What tests are performed to confirm the amyloidosis diagnosis?
Blood tests
The results of blood tests can also indicate amyloidosis.
A high platelet count occurs in 5 to 10% of people with amyloidosis and may be a clue to the diagnosis.
Levels of serum alkaline phosphatase (an enzyme in the bone and the liver) may increase and occurs in about 25% of the patients with amyloidosis.
A low hemoglobin level (anemia) is not a prominent feature of amyloidosis but may occur due to kidney dysfunction, multiple myeloma or stomach bleeding. Low blood protein levels could occur because of a loss of protein through the urine and could result in increased cholesterol and triglyceride levels.
Electrocardiogram
An electrocardiogram (EKG) is a test that detects and records the flow of electrical impulses throughout the heart. When an EKG is performed on a person with amyloidosis, low voltage and false signs of heart attack may appear.
Biopsy
A biopsy, which can detect the presence of amyloids in tissues or organs, is necessary to confirm the diagnosis. The most common biopsy sites include abdominal fat, rectum, gums and bone marrow. Biopsies of the kidneys, nerves, heart or liver are sometimes performed to confirm the diagnosis.
How is amyloidosis treated?
There is no known cure for amyloidosis, and no treatment has been found effective in reversing the deposits of amyloids. However, there are treatments that can slow the progression of amyloidosis and reduce its harmful effects on certain organs.
Because each type of amyloidosis is different, the treatment will be tailored to each individual. The treatment will depend on several factors, including the organs or tissues that are affected; the severity of symptoms; and the person's age, overall health and medical history.
In secondary amyloidosis, treatment is aimed at relieving the underlying disease. People with renal amyloidosis may be candidates for kidney dialysis or transplantation. Localized amyloid tumors can be surgically removed, generally without recurrence.
Treatment with chemotherapy that is known to be effective against multiple myeloma and other related diseases has been attempted. More recently, therapy with high dose steroids and alpha-interferons appear to be showing promising results and is currently under investigation. Treatment with cochicine (a drug used to treat some forms of arthritis and cancer) has shown to slow the progression of amyloidosis.
Preliminary research shows that high dose chemotherapy followed by bone marrow transplantation may be an effective treatment. However, further investigation is needed.
What is the outlook?
Amyloidosis is chronic and usually progresses slowly over a number of years. The severity of the disease depends on which organs are affected by the amyloid deposits. Amyloidosis can be potentially life-threatening when the kidneys and heart are affected.
Early diagnosis is the key to managing the disease before it becomes fatal. The outlook for people with primary amyloidosis has improved due to earlier diagnosis, improved supportive care, and advances in medical management of the disease.
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More information about this disease can be found at the Amyloidosis Research Foundation
