Amyloidosis (am-uh-loi-DO-sis) is a rare disease that occurs when an abnormal protein, called amyloid, builds up in your organs and interferes with their normal function.

Amyloid isn't normally found in the body, but it can be formed from several different types of protein. Organs that may be affected include the heart, kidneys, liver, spleen, nervous system and digestive tract.

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

Treatments may include chemotherapy similar to that used to combat cancer. Your doctor may suggest medications to reduce amyloid production and to control symptoms. Some people may benefit from organ or stem cell transplants.

You may not experience signs and symptoms of amyloidosis until the condition is advanced. When signs and symptoms are evident, they depend on which of your organs are affected.

Signs and symptoms of amyloidosis may include:

• Swelling of your ankles and legs
• Severe fatigue and weakness
• Shortness of breath with minimal exertion
• Unable to lie flat in bed due to shortness of breath
• Numbness, tingling or pain in your hands or feet, especially pain in your wrist (carpal tunnel syndrome)
• Diarrhea, possibly with blood, or constipation
• Unintentional weight loss of more than 10 pounds (4.5 kilograms)
• An enlarged tongue, which sometimes looks rippled around its edge
• Skin changes, such as thickening or easy bruising, and purplish patches around the eyes
• An irregular heartbeat
• Difficulty swallowing

When to see a doctor

See your doctor if you persistently experience any of the signs or symptoms associated with amyloidosis.

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

Subtypes of amyloidosis include:

• AL amyloidosis (immunoglobulin light chain amyloidosis). 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. Also known as secondary amyloidosis, this variety is usually triggered by an inflammatory disease, such as rheumatoid arthritis. Improved treatments for severe inflammatory conditions have resulted in a sharp decline in the number of cases of AA amyloidosis in developed countries. 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 of amyloidosis occurs when the TTR protein made by the liver is normal but produces amyloid for unknown reasons. Formerly known as senile systemic amyloidosis, wild-type amyloidosis tends to affect men over age 70 and typically 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.

Factors that increase your risk of amyloidosis include:

• Age. Most people diagnosed with amyloidosis are between ages 60 and 70, although earlier onset occurs.
• Sex. Amyloidosis occurs more commonly in men.
• Other diseases. Having a chronic infectious or inflammatory disease increases your 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.

The potential complications of amyloidosis depend on which organs the amyloid deposits affect. Amyloidosis can seriously damage your:

• Heart. Amyloid reduces your heart's ability to fill with blood between heartbeats. Less blood is pumped with each beat, and you may experience shortness of breath. If amyloidosis affects your heart's electrical system, your heart rhythm may be disturbed. Amyloid-related heart problems can become life-threatening.
• Kidneys. Amyloid can harm the kidneys' filtering system, causing protein to leak from your blood into your urine. The kidneys' ability to remove waste products from your body is lowered, which may eventually lead to kidney failure and the need for dialysis.
• Nervous system. You may experience pain, numbness or tingling of your fingers or numbness, lack of feeling or a burning sensation in your toes or the soles of your feet. If amyloid affects the nerves that control your bowel function, you may experience periods of alternating constipation and diarrhea. If it affects the nerves that control blood pressure, you may feel faint after standing up too quickly.

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

Early diagnosis can help prevent further organ damage. Precise diagnosis is important because treatment varies greatly, depending on your specific condition.

Laboratory tests

Your blood and urine may be analyzed for abnormal protein that can indicate amyloidosis. Depending on your signs and symptoms, you may also have thyroid and liver function tests.

Biopsy

A tissue sample may be taken and checked for signs of amyloidosis. The biopsy may be taken from the fat under the skin on your abdomen (fat aspirate), bone marrow, or an affected organ — such as your liver or kidney. Specialized testing of the tissue can help determine the type of amyloid deposit.

Imaging tests

Images of the organs affected by amyloidosis can help establish the extent of your disease. Tests may include:

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

There's no cure for amyloidosis. But treatment can help manage signs and symptoms and limit further production of amyloid protein. If the amyloidosis has been triggered by another condition, such as rheumatoid arthritis or tuberculosis, treating the underlying condition can be helpful.

Medications

• Chemotherapy. Many of the same types of medicines used to treat some forms of cancer are used in AL amyloidosis to stop the growth of abnormal cells that produce the protein leading to formation of amyloid.
• Heart medications. If your heart is affected, your doctor may suggest blood thinners to reduce the risk of clots and medications to control your heart rate. You may also need to restrict your salt intake and take drugs that increase urination, which can reduce the strain on your heart and kidneys.
• Targeted therapies. For certain types of amyloidosis, drugs such as patisiran (Onpattro) and inotersen (Tegsedi) can interfere with the commands sent by faulty genes that create amyloid. Other drugs, such as tafamidis (Vyndamax, Vyndaqel) and diflunisal, can stabilize bits of protein in the bloodstream and prevent them from getting transformed into amyloid deposits.

Surgical and other procedures

• Autologous blood stem cell transplant. This procedure involves collecting your own stem cells from your blood through a vein and storing them for a short time while you have high-dose chemotherapy. The stem cells are then returned to your body via a vein. This treatment is most appropriate for people whose disease isn't advanced and whose heart isn't greatly affected.
• 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. Your doctor might suggest surgery to replace your heart or kidneys if amyloid deposits have severely damaged those organs. Some types of amyloid are formed in the liver, so a liver transplant could halt that production.

You may be referred to a doctor who specializes in blood disorders (hematologist).

What you can do

• Write down your symptoms, including any that may seem unrelated to the reason why you scheduled the appointment.
• Make a list of all your medications, vitamins and supplements.
• 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 doctor.
• Ask a relative or friend to accompany you, to help you remember what the doctor says.

Questions to ask your doctor

• 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 doctor, don't hesitate to ask other questions during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may provide time to go over points you want to spend more time on. You may be asked:

• When did you first begin experiencing symptoms? 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 normal daily tasks? Are you often tired?
• Have you noticed that you bruise easily?
• Has anyone in your family ever been diagnosed with amyloidosis?