Amyloidosis

What is it?
Amyloidosis is a progressive disease in which deposits of a waxy, starch-like protein called amyloid accumulate in one or more organs or body systems. Amyloid proteins are not usually found in the body, but are manufactured by malfunctioning bone marrow. As the amyloid deposits build up, they begin to interfere with the normal function of the organ or body system.
Who gets it?
Amyloidosis occurs in only eight of every one million people. Symptoms usually occur after age 40. Males and females are equally affected.
What causes it?
There are at least 15 different types of amyloidosis. The major forms are primary, secondary, and hereditary. The cause of primary amyloidosis is not known. However, it is associated with abnormalities in blood cells because it often occurs in people with bone marrow cancer (multiple myeloma). Secondary amyloidosis occurs in people who have a chronic infection or inflammatory disease, such as tuberculosis, a bacterial infection called familial Mediterranean fever, bone infections (osteomyelitis), rheumatoid arthritis, inflammation of the small intestine (granulomatous ileitis), Hodgkin's disease, and leprosy. Hereditary amyloidosis occurs in most ethnic groups, and is the only inherited form of the disease. Researchers believe a child needs to receive just one copy of the defective gene to inherit amyloidosis. This pattern of inheritance is called autosomal dominance. If one parent has hereditary amyloidosis, the child will have a 50% chance of developing the disease. There is also a form of amyloidosis associated with Alzheimer's disease.
What are the symptoms?
Symptoms of amyloidosis depend upon the area of the amyloid deposits and can range from mild to severe. In some cases, amyloidosis can cause organ failure and death. The areas typically affected include the heart, gastrointestinal system, kidneys, liver and spleen, lungs, skin, thyroid and adrenal glands, lymph nodes, and blood vessels. Amyloid deposits in the heart make it difficult for the heart to function properly, resulting in shortness of breath, irregular heartbeat, and congestive heart failure. Symptoms of amyloid in the gastrointestinal system include a tongue that is thick and inflamed, signs of malnutrition caused by poor absorption of food, intestinal bleeding, abdominal pain, constipation, and diarrhea. Kidney damage is indicated by swelling in the feet and legs, protein in the urine, high cholesterol that cannot be reduced with medication, and a distaste for foods rich in protein. The liver and spleen will enlarge, and the spleen can rupture as amyloid accumulates. Amyloid deposits in the sinuses, larynx, and trachea will block the airways, making breathing difficult. Approximately half of all people with primary or secondary amyloidosis have skin symptoms. These include waxy-looking raised bumps, called papules, usually located on the face and neck; in the groin, armpits, or anal area; on the tongue; or in the ear canals. Patients may also have skin swelling, hair loss, and dry mouth. Amyloidosis can affect blood clotting, so symptoms may include abnormal bleeding or bruising. Hereditary amyloidosis almost always affects the nervous system. Symptoms may include inflammation and degeneration of the peripheral nerves (peripheral neuropathy), carpal tunnel, weakness, and abnormal sensations.
How is it diagnosed?
If your doctor suspects you have amyloidosis, either because of organ failure or unexplained bleeding, he or she may order blood and urine tests to check for the amyloid protein. A definite diagnosis is made through a tissue sample (biopsy) from the liver, kidney, skin, gums, or rectum. A bone marrow biopsy might also be performed. Other laboratory and imaging tests can confirm the exact organ or system that is affected. The affected organs are usually enlarged, and feel rubbery and firm.
What is the treatment?
Treatment for amyloidosis is determined by the type and extent of the disease. Drugs such as colchicin, prednisone, and other anti-inflammatories are commonly used to slow or stop the progression of this disease. In fact, cholchicine has been known to prevent amyloidosis in patients with familial Mediterranean fever. Chemotherapy drugs, such as melphalan, may also be used to treat this disease. Doctors have found that patients are able to tolerate higher doses of melphalan, which are more effective against amyloidosis, if they undergo bone marrow or stem cell transplants. All blood cells originate from stem cells, which are found in the bone marrow. In cases of secondary amyloidosis, where amyloid deposits are caused by another disease, treating that disease can slow down or even reverse amyloidosis. Symptoms caused by heart or kidney damage are usually treated with medication and dialysis. Heart and kidney transplants may be considered; however, there is a possibility that amyloid will again build up in the new organ. Amyloid deposits sometimes can be surgically removed from a specific area of the body. Surgery can also be performed to relieve nerve pressure in people with hereditary amyloidosis
Self-care tips
The long-term outlook for people with amyloidosis depends upon the extent of the disease. If there is a history of hereditary amyloidosis in your family, you may want to seek genetic counseling before having children.