Amyloidosis is when an abnormal protein called amyloid builds up in your tissues and organs. When it does, it affects their shape and how they work. Amyloidosis is a serious health problem that can lead to life-threatening organ failure.
Causes and Types of Amyloidosis
Many different proteins can lead to amyloid deposits, but only a few have been linked to major health problems. The type of protein and where it collects tells the type of amyloidosis you have. Amyloid deposits may collect throughout your body or in just one area.
The different types of amyloidosis include:
AL amyloidosis (immunoglobulin light chain amyloidosis). This is the most common type and used to be called primary amyloidosis. AL stands for “amyloid light chains,” which is the type of protein responsible for the condition. There’s no known cause, but it happens when your bone marrow makes abnormal antibodies that can’t be broken down. It’s linked with a blood cancer called multiple myeloma. It can affect your kidneys, heart, liver, intestines, and nerves.
AA amyloidosis. Previously known as secondary amyloidosis, this condition is the result of another chronic infectious or inflammatory disease such as rheumatoid arthritis, Crohn’s disease, or ulcerative colitis. It mostly affects your kidneys, but it can also upset your digestive tract, liver, and heart. AA means the amyloid type A protein causes this type.
Dialysis-related amyloidosis (DRA). This is more common in older adults and people who have been on dialysis for more than 5 years. This form of amyloidosis is caused by deposits of beta-2 microglobulin that build up in the blood. Deposits can build up in many different tissues, but it most commonly affects bones, joints, and tendons.
Familial, or hereditary, amyloidosis. This is a rare form passed down through families. It often affects the liver, nerves, heart, and kidneys. Many genetic defects are linked to a higher chance of amyloid disease. For example, an abnormal protein like transthyretin (TTR) can be the cause.
Age-related (senile) systemic amyloidosis. This is caused by deposits of normal TTR in the heart and other tissues. It happens most commonly in older men.
Organ-specific amyloidosis. This causes deposits of amyloid protein in single organs, including the skin (cutaneous amyloidosis).
Though some types of amyloid deposits have been linked to Alzheimer's disease, the brain is rarely affected by amyloidosis that happens throughout your body.
Risk Factors for Amyloidosis
Men get amyloidosis more often than women. Your risk for amyloidosis goes up as you grow older. Amyloidosis affects 15% of patients with a form of cancer called multiple myeloma.
Amyloidosis may also happen in people with end-stage kidney disease who are on dialysis for a long time (see "Dialysis-related amyloidosis" above).
Symptoms of Amyloidosis
Symptoms of amyloidosis are often subtle. They can also vary greatly depending on where the amyloid protein is collecting in the body. It is important to note that the symptoms described below may be due to a variety of health problems. Only your doctor can make a diagnosis of amyloidosis.
General symptoms of amyloidosis may include:
- Changes in skin color
- Severe fatigue
- Feeling of fullness
- Joint pain
- Low red blood cell count (anemia)
- Shortness of breath
- Swelling of the tongue
- Tingling and numbness in legs and feet
- Weak hand grip
- Severe weakness
- Sudden weight loss
Cardiac (Heart) Amyloidosis
Amyloid deposits in the heart can make the walls of the heart muscle stiff. They can also make the heart muscle weaker and affect the electrical rhythm of the heart. This condition can cause less blood to flow to your heart. Eventually, your heart will no longer be able to pump normally. If amyloidosis affects your heart, you may have:
- Shortness of breath with light activity
- An irregular heartbeat
- Signs of heart failure, including swelling of the feet and ankles, weakness, fatigue, and nausea, among others
Renal (Kidney) Amyloidosis
Your kidneys filter waste and toxins from your blood. Amyloid deposits in the kidneys make it hard for them to do this job. When your kidneys do not work properly, water and dangerous toxins build up in your body. If amyloidosis affects the kidneys, you may have:
- Signs of kidney failure, including swelling of the feet and ankles and puffiness around the eyes
- High levels of protein in your urine
Amyloid deposits along your gastrointestinal (GI) tract slow down the movement of food through your intestines. This interferes with digestion. If amyloidosis affects your GI tract, you may have:
- Less appetite
- Stomach pain
- Weight loss
If your liver is affected, that can cause liver enlargement and fluid buildup in the body.
Amyloid deposits can damage the nerves outside your brain and spinal cord, called the peripheral nerves. The peripheral nerves carry information between your brain and spinal cord and the rest of your body. For example, they make your brain perceive pain if you burn your hand or stub your toes. If amyloidosis affects your nerves, you may have:
- Balance problems
- Problems controlling your bladder and bowel
- Sweating problems
- Tingling and weakness
- Lightheadedness when standing due to a problem with your body's ability to control blood pressure
A thorough physical exam and a detailed and accurate account of your medical history are crucial in helping your doctor diagnose amyloidosis.
Blood and urine tests can spot abnormal proteins. Depending on your symptoms, your doctor may also check your thyroid and liver.
Your doctor will do a biopsy to confirm a diagnosis of amyloidosis and know the specific type of protein you have. The tissue sample for the biopsy may be taken from your belly fat (the abdominal fat pad), bone marrow, or sometimes your mouth, rectum, or other organs. It's not always necessary to biopsy the part of the body damaged by the amyloid deposits.
Imaging tests can also help. They show the amount of damage to organs like your heart, liver, or spleen.
Your doctor will do a genetic test if they think you have a type that is passed down through families. Treatment for hereditary amyloidosis is different from treatment for other types of the disease.
Once you’re diagnosed, your doctor might check your heart with an echocardiogram or your liver and spleen with imaging tests.
There is no cure for amyloidosis. Your doctor will prescribe treatments to slow the development of the amyloid protein and manage your symptoms. If amyloidosis is related to another condition, then treatment will include targeting that underlying condition.
Specific treatment depends on what type of amyloidosis you have and how many organs are affected.
- High-dose chemotherapy with stem cell transplant can help remove the substance that leads to amyloid formation in some people with primary AL amyloidosis. Chemotherapy medicines alone may be used to treat other patients with primary AL amyloidosis.
- Secondary (AA) amyloidosis is treated by controlling the underlying disorder and with powerful anti-inflammatory medicines called steroids, which fight inflammation.
- A liver transplant may treat the disease if you have certain types of hereditary amyloidosis.
- New therapies can slow the production of the abnormal protein TTR in hereditary amyloidosis.
- Your doctor might also recommend a kidney transplant.
Other treatments to help with symptoms include:
- Diuretic medicine to remove extra water from your body
- Thickeners to add to fluids to prevent choking if you have trouble swallowing
- Compression stockings to relieve swelling in your legs or feet
- Changes to what you eat, especially if you have gastrointestinal amyloidosis
What to Expect
Amyloidosis can be deadly, especially if it affects your heart or kidneys. Early diagnosis and treatment are important and can help improve survival.
Researchers continue to question why some types of amyloid make people sick and how the formation of amyloid can be stopped. Studies to investigate new treatments are ongoing. If you have amyloidosis, consider asking your doctor if there are any clinical trials you can join, or search for one by visiting www.clinicaltrials.gov and typing in the search term "amyloidosis."