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 affect the way organs work.

Amyloidosis may affect the heart, kidneys, liver, spleen, nervous system, soft tissue, muscle and digestive tract.

There are many different types of amyloidosis. Some occur with other diseases and improve with treatment. Other types may lead to life-threatening organ failure.

Treatments may include chemotherapy medicines used to treat cancer. Other medicines can reduce amyloid production and manage symptoms. Some people may benefit from organ or blood stem cell transplants.

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, also called immunoglobulin light chain amyloidosis. This is one of the most common types of amyloidosis in developed countries. AL amyloidosis used to be called primary amyloidosis. It often affects the heart, kidneys, liver and nerves. It can be associated with multiple myeloma or other blood conditions.
• Wild-type ATTR amyloidosis, also called transthyretin amyloidosis. This type also has been called senile systemic amyloidosis. It occurs when the transthyretin protein, also called TTR, made by the liver produces amyloid for unknown reasons. Wild-type ATTR amyloidosis tends to affect men over age 60 and often targets the heart. It also can cause carpal tunnel syndrome.
• Hereditary ATTR amyloidosis, also called familial transthyretin amyloidosis. This inherited condition often affects the nerves, heart and kidneys. It most commonly happens with changes to the TTR protein made by your liver. This altered protein is passed down through families.
• Other hereditary forms of amyloidosis. There are other hereditary forms of amyloidosis. These are more rare. They can affect different organs, depending on the type and how proteins are affected. Examples include apolipoprotein A-1 amyloidosis, gelsolin amyloidosis and fibrinogen amyloidosis.
• AA amyloidosis. This is also known as secondary amyloidosis. It's often triggered by a chronic inflammatory disease, such as rheumatoid arthritis. It most commonly affects the kidneys, liver and spleen.
• Localized amyloidosis. This type of amyloidosis has a better prognosis than varieties that affect multiple organ systems. It is, however, not common. Typical sites for localized amyloidosis include the bladder, skin, throat or lungs. Correct diagnosis is important so treatments that affect the entire body can be avoided.

Factors that increase the risk of amyloidosis include:

• Age. Most people diagnosed with amyloidosis are over the age of 50.
• Sex assigned at birth. 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.
• Dialysis. Dialysis can't always remove large proteins from the blood. If you're on dialysis, certain 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 version of the TTR protein that is associated with a type of amyloidosis that can harm the heart.

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.

Amyloidosis is often overlooked because the symptoms can mimic those of more-common diseases.

Early diagnosis can help prevent further organ damage. Precise diagnosis of the type of amyloidosis you have is important. Treatment varies greatly, depending on your specific condition.

Laboratory tests

Blood and urine may be analyzed for proteins that can indicate amyloidosis. People with certain symptoms also may need thyroid and kidney function tests.

Biopsy

A tissue sample can be checked for signs of amyloidosis. The biopsy may be taken from the fat under the skin on the belly or from bone marrow. Some people may need a biopsy of an affected organ, such as the liver or kidney. The tissue can be tested to see what type of amyloid is involved.

Imaging tests

Images of the organs affected by amyloidosis may include:

• Echocardiogram. This technology uses sound waves to create moving images that can show how well the heart is working. It also can show heart damage that can be specific to amyloidosis.
• MRI. MRI uses radio waves and a strong magnetic field to create detailed images of organs and tissues. These images can be used to check the structure and function of the heart. MRI can be useful in diagnosing whether amyloidosis is affecting the heart.
• Nuclear imaging. In this test, tiny amounts of radioactive material, called tracers, are injected into a vein. This can reveal early heart damage caused by certain types of amyloidosis. It also can help distinguish between different types of amyloidosis, which can guide treatment decisions.

There's no cure for amyloidosis. But treatment can help to slow or stop the production of amyloid protein. Treatment can improve symptoms and potentially extend life expectancy. If the amyloidosis has been triggered by another condition, such as rheumatoid arthritis or tuberculosis, treating the underlying condition can be helpful.

Medicines

• Chemotherapy. Some cancer medicines are used for AL amyloidosis to stop the growth of cells that produce the protein that forms amyloid. Most people start therapy that contains daratumumab (Darzalex), which is a monoclonal antibody used to treat multiple myeloma.
• ATTR therapies. Drugs such as tafamidis (Vyndamax; Vyndaqel) and acoramidis (Attruby) have been approved to treat ATTR amyloidosis. These medicines have been shown to slow down the buildup of amyloid in the heart, improve symptoms and prolong life expectancy. Patisiran (Onpattro), eplontersen (Wainua) and vutrisiran (Amvuttra) also are approved for people with familial ATTR amyloidosis. These medicines interfere with the production of the TTR protein in the liver. This helps prevent amyloid buildup.
• Heart medicines. If your heart is affected, you may need to take blood thinners to reduce the risk of clots. You also may need medicines to control your heart rate. Some medicines increase urination, which can reduce the strain on your heart and kidneys.

Surgical and other procedures

• Autologous blood stem cell transplant. This procedure involves collecting your own stem cells from your blood and storing them for a short time while you have high-dose chemotherapy. The stem cells are then returned to your body. The blood stem cells are collected and returned through a vein. This treatment is most appropriate for people with AL amyloidosis whose disease isn't advanced and whose heart isn't greatly affected. Stem cell transplant is used for people who did not respond well to other treatments for AL amyloidosis.
• Dialysis. If your kidneys have been damaged by amyloidosis, you may need to start dialysis. This procedure uses a machine to filter wastes, salts and fluid from your blood on a regular schedule.
• Organ transplant. If amyloid deposits have severely damaged your heart or kidneys, you might need surgery to replace those organs. Some types of amyloid are formed in the liver, so a liver transplant could stop that production.

You may be referred to a healthcare professional who specializes in blood disorders called a hematologist.

What you can do

When you make the appointment, ask if there's anything you need to do in advance. It may be helpful to:

• Write down your symptoms, including any that may seem unrelated to the reason you scheduled the appointment.
• Make a list of all your medications, vitamins and supplements, including the doses.
• Write down your key medical information, including other conditions.
• Write down key personal information, including any recent changes or stressors in your life.
• Write down questions to ask your healthcare team.
• Ask a relative or friend to go with you, to help you remember what the care team says.

For amyloidosis, some basic questions to ask your healthcare professional include:

• What's the most likely cause of my symptoms?
• What type of amyloidosis do I have?
• What organs are affected?
• What stage is my disease?
• What kinds of tests do I need?
• What kind of treatments do I need?
• Am I at risk of long-term complications?
• What types of side effects can I expect from treatment?
• Do I need to follow any dietary or activity restrictions?
• I have another health condition. How can I best manage them together?

In addition to the questions that you've prepared to ask your care team, don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your healthcare team is likely to ask you several questions, such as:

• When did your symptoms begin? How severe are they, and are they continuous or occasional?
• Does anything seem to make your symptoms better or worse?
• How is your appetite? Have you recently lost weight without trying?
• Have you experienced any leg swelling?
• Have you experienced shortness of breath?
• Are you able to work and perform your usual daily tasks? Are you often tired?
• Have you noticed that you bruise easily?
• Has anyone in your family ever been diagnosed with amyloidosis?