HEART & BLOOD Blood/Lymphatic System • Hemophilia • Amyloidosis • Giant cell arteritis • Vasculitis • Thrombocytopenia (low platelet count) • Behcet's disease • Takayasu's arteritis • Wegener's granulomatosis • Idiopathic thrombocytopenic purpura • Churg-Strauss syndrome

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Amyloidosis is a rare and potentially fatal disease that occurs when substances called amyloid proteins build up in your body's organs. Amyloid is an abnormal protein usually produced by cells in your bone marrow that can be deposited in any tissue or organ. Amyloidosis frequently affects the heart, kidneys, liver, spleen, nervous system and gastrointestinal tract.

Amyloidosis can affect different organs in different people, and there are many types of amyloid. The different types are defined by where the amyloid building blocks come from. The most common type of the disease, primary systemic amyloidosis, is a bone marrow disorder. Other types that come from the liver are considered familial, or inherited. In still other cases, amyloidosis may occur as a result of kidney disease in people who have undergone long-term dialysis therapy.

The exact cause of amyloidosis is unknown, and there's no cure for amyloidosis. However, medications and special diets can help you manage your symptoms and limit the production of amyloid protein.

Signs and symptoms of amyloidosis depend on the organs affected. The wide range of signs and symptoms often makes amyloidosis difficult to diagnose. You may even have no symptoms. Signs and symptoms may include:

• Swelling of your ankles and legs
• Weakness
• Weight loss
• Shortness of breath
• Numbness or tingling in your hands or feet
• Diarrhea
• Severe fatigue
• An enlarged tongue (macroglossia)
• Skin changes
• An irregular heartbeat
• Difficulty swallowing

Doctors classify amyloidosis into three major forms:

• Primary amyloidosis. This most common form of amyloidosis primarily affects your heart, kidneys, tongue, nerves and intestines. Primary amyloidosis isn't associated with other diseases except for multiple myeloma, in a minority of cases.

  The cause of primary amyloidosis is unknown, but doctors do know that the disease begins in your bone marrow. In addition to producing red and white blood cells and platelets, your bone marrow makes antibodies — proteins that protect you against infection and disease. After antibodies serve their function, your body breaks them down and recycles them. Amyloidosis occurs when cells in the bone marrow produce antibodies that can't be broken down. These antibodies then build up in your bloodstream. Ultimately, they leave your bloodstream and can deposit in your tissues as amyloid, interfering with normal function.

• Secondary amyloidosis. This form occurs in association with chronic infectious or inflammatory diseases, such as tuberculosis, rheumatoid arthritis or osteomyelitis, a bone infection. It primarily affects your kidneys, spleen, liver and lymph nodes, though other organs may be involved. Treatment of the underlying disease may help stop this form of amyloidosis.
• Hereditary amyloidosis. As the name implies, this form of amyloidosis is inherited. This type often affects the nerves, heart and kidneys.

Anyone can develop primary systemic amyloidosis, but certain factors place you at greater risk:

• Age. The majority of people who get amyloidosis are older than 40.
• Sex. Men are much more likely than women to develop the disorder.
• Other diseases. You may be at increased risk if you have a chronic infectious or inflammatory disease. Ten percent to 15 percent of people who have multiple myeloma — a form of bone marrow cancer — develop amyloidosis.
• Family history. Some cases of amyloidosis are inherited.
• Kidney dialysis. If you have kidney disease requiring kidney dialysis — particularly for longer than five years — you may be at increased risk of dialysis-associated amyloidosis. This is because dialysis can't remove large proteins from the blood, so abnormal proteins may build up and deposit in surrounding tissues. This condition is rare with modern dialysis techniques.

Although amyloid is an abnormal protein, the amount of protein you eat plays no role in the development of the disease. Also, there's no recognized link between amyloidosis and stress or occupation.

If you persistently experience any of the signs or symptoms listed earlier, they may indicate amyloidosis or other serious diseases. See your doctor to determine the underlying cause.

In order to rule out other conditions, your doctor may conduct a physical exam and a variety of tests, including blood and urine tests.

Though blood or urine tests may detect an abnormal protein — which could indicate amyloidosis — the only definitive test for amyloidosis is a tissue biopsy. In this biopsy, the doctor uses a needle to remove a small sample of tissue. If your doctor suspects that you have systemic amyloidosis — meaning it affects several parts of your body rather than just one organ — the biopsy may be taken from your abdominal fat, bone marrow or rectum. The sample is then examined under a microscope in a laboratory to check for signs of amyloid. These biopsies are conducted in an outpatient setting with a numbing medication (local anesthetic).

Occasionally, tissue samples may be taken from other parts of your body, such as your liver or kidney, to help diagnose the specific organ affected by amyloidosis. These procedures may require hospitalization.

The severity of amyloidosis depends on which organs the amyloid deposits affect. Potentially life-threatening situations include kidney failure and congestive heart failure:

• Kidney damage. When amyloidosis affects your kidneys, their filtering system is damaged, causing protein to leak from your blood into your urine. When large amounts of protein leave the bloodstream and appear in the urine, the loss of protein from your blood causes fluid to leak out of the blood vessels. This, along with retention of sodium, can cause your feet, ankles and calves to swell (edema). Ultimately, damage to the kidneys' filtering system inhibits your kidneys' ability to remove waste products from your body, which may progress to kidney failure.
• Heart damage. When amyloidosis affects your heart, the most common symptom is shortness of breath, even with the slightest exertion. You may find it difficult to climb a flight of stairs or walk long distances without stopping to rest. When amyloid protein builds up in your heart, it reduces your heart's ability to fill with blood in between heartbeats. This means less blood is pumped with each beat. Your heart will have difficulty keeping up with your body's demand for blood during exertion. And when amyloidosis affects the electrical system of your heart, this may disturb your heart's rhythm.
• Nervous system damage. Another potential complication of amyloidosis is disruption of your nervous system function. In about 50 percent of people with amyloidosis, this may include carpal tunnel syndrome — characterized by pain, numbness or tingling of the fingers. Disruption of another area of your nervous system might cause numbness or a lack of feeling in your toes or soles of your feet, or a burning sensation in these areas due to nerve irritation.

  If amyloid deposits affect the nerves that control your bowel function, you may experience periods of alternating constipation and diarrhea. Sometimes the condition affects nerves that control blood pressure, and you may experience dizziness or near fainting when standing too quickly as a result of a drop in your blood pressure.

Though there's no cure for amyloidosis, treatment may help manage symptoms and limit further production of amyloid protein. Managing amyloidosis is primarily done with medications and diet. Well-balanced nutrition is important to provide your body with an adequate energy supply.

Treating complications
Because amyloidosis can cause a number of complications, you may also need treatment — such as a special diet — for those specific conditions, based on your signs and symptoms and affected organs. For example, if amyloidosis affects your heart or kidneys, you may be asked to follow a low-salt diet to control fluid retention. Or your doctor may prescribe diuretics and other medications. In some cases, your doctor might prescribe medication for pain control.

If you have secondary amyloidosis, the primary goal of therapy is to treat the underlying condition — for example, taking an anti-inflammatory medication for rheumatoid arthritis.

Researchers are studying other therapies to determine their place in the treatment of amyloidosis. Ask your doctor whether these treatments are appropriate for you. For primary systemic amyloidosis, some of these include:

• Peripheral blood stem cell transplantation. Peripheral blood stem cell transplantation involves using high-dose chemotherapy and transfusion of previously collected immature blood cells (stem cells) to replace diseased or damaged marrow. These cells may be your own (autologous transplant) or from a donor (allogeneic transplant). Autologous transplant is currently the preferred standard.
• Medicines. Therapies include melphalan (Alkeran), an agent also used to treat certain types of cancer, and prednisone, a corticosteroid used for its anti-inflammatory effects. Other types of chemotherapy regimens — such as melphalan with high-dose dexamethasone or VAD, which stands for vincristine, Adriamycin and Dexamethasone — are being tested in amyloidosis. Several medications — such as thalidomide, a drug now used to treat multiple myeloma — are being tested for their ability to inhibit the disease. Your doctor may be aware of clinical trials available to you.

For hereditary amyloidosis, one possible therapy may be liver transplantation because the protein that causes this form of amyloidosis is made in the liver.

If you feel short of breath, take a rest. Although you'll need to avoid strenuous activities, you may be able to continue normal daily activities, like going to work. Talk to your doctor about what's an appropriate level of activity for you.