Overview

Amyloidosis (am-uh-loi-DO-sis) is a rare disease that occurs when a protein called amyloid builds up in organs. This amyloid buildup can make the organs not work properly.

Organs that may be affected include the heart, kidneys, liver, spleen, nervous system and digestive tract.

Some types of amyloidosis occur with other diseases. These types may improve with treatment of the other diseases. Some types of amyloidosis may lead to life-threatening organ failure.

Treatments may include chemotherapy with strong drugs used to treat cancer. Other types of medications can reduce amyloid production and control symptoms. Some people may benefit from organ or stem cell transplants.

Symptoms

You may not experience symptoms of amyloidosis until later in the course of the disease. Symptoms may vary, depending on which organs are affected.

Signs and symptoms of amyloidosis may include:

  • Severe fatigue and weakness
  • Shortness of breath
  • Numbness, tingling, or pain in the hands or feet
  • Swelling of the ankles and legs
  • Diarrhea, possibly with blood, or constipation
  • An enlarged tongue, which sometimes looks rippled around its edge
  • Skin changes, such as thickening or easy bruising, and purplish patches around the eyes

When to see a doctor

See your health care provider if you regularly experience any of the signs or symptoms associated with amyloidosis.

Causes

There are many different types of amyloidosis. Some types are hereditary. Others are caused by outside factors, such as inflammatory diseases or long-term dialysis. Many types affect multiple organs. Others affect only one part of the body.

Types of amyloidosis include:

  • AL amyloidosis (immunoglobulin light chain amyloidosis). This is the most common type of amyloidosis in developed countries. AL amyloidosis is also called primary amyloidosis. It usually affects the heart, kidneys, liver and nerves.
  • AA amyloidosis. This type is also known as secondary amyloidosis. It's usually triggered by an inflammatory disease, such as rheumatoid arthritis. It most commonly affects the kidneys, liver and spleen.
  • Hereditary amyloidosis (familial amyloidosis). This inherited disorder often affects the nerves, heart and kidneys. It most commonly happens when a protein made by your liver is abnormal. This protein is called transthyretin (TTR).
  • Wild-type amyloidosis. This variety has also been called senile systemic amyloidosis. It occurs when the TTR protein made by the liver is normal but produces amyloid for unknown reasons. Wild-type amyloidosis tends to affect men over age 70 and often targets the heart. It can also cause carpal tunnel syndrome.
  • Localized amyloidosis. This type of amyloidosis often has a better prognosis than the varieties that affect multiple organ systems. Typical sites for localized amyloidosis include the bladder, skin, throat or lungs. Correct diagnosis is important so that treatments that affect the entire body can be avoided.

Risk factors

Factors that increase the risk of amyloidosis include:

  • Age. Most people diagnosed with amyloidosis are between ages 60 and 70.
  • Sex. Amyloidosis occurs more commonly in men.
  • Other diseases. Having a chronic infectious or inflammatory disease increases the risk of AA amyloidosis.
  • Family history. Some types of amyloidosis are hereditary.
  • Kidney dialysis. Dialysis can't always remove large proteins from the blood. If you're on dialysis, abnormal proteins can build up in your blood and eventually be deposited in tissue. This condition is less common with more modern dialysis techniques.
  • Race. People of African descent appear to be at higher risk of carrying a genetic mutation associated with a type of amyloidosis that can harm the heart.

Complications

Amyloidosis can seriously damage the:

  • Heart. Amyloid reduces the heart's ability to fill with blood between heartbeats. Less blood is pumped with each beat. This can cause shortness of breath. If amyloidosis affects the heart's electrical system, it can cause heart rhythm problems. Amyloid-related heart problems can become life-threatening.
  • Kidneys. Amyloid can harm the kidneys' filtering system. This affects their ability to remove waste products from the body. It can eventually cause kidney failure.
  • Nervous system. Nerve damage can cause pain, numbness, or tingling of the fingers and feet. If amyloid affects the nerves that control bowel function, it can cause periods of alternating constipation and diarrhea. Damage to the nerves that control blood pressure can make people feel faint if they stand up too quickly.
By Mayo Clinic Staff