AL amyloidosis, which is also called amyloid light-chain amyloidosis or primary amyloidosis, can affect many different organs. It most commonly leads to problems with the heart and the kidneys. About 70 percent of people with AL amyloidosis have amyloid deposits in one or both of these organs. This condition can also affect the nervous system, digestive system, and skin. In fact, AL amyloidosis can affect any type of tissue except for the brain and spinal cord.
Some people with AL amyloidosis may only have one affected organ, but most people experience problems with multiple organs, especially as the disease progresses. People who have amyloid deposits in more than one organ are more likely to have a worse prognosis. Your affected organs may play a role in which symptoms you experience, the treatments you receive, and the outlook you have.
Amyloidosis is caused by abnormal proteins that attach together, forming clumps. These clumps can be deposited in different organs and tissues. As more amyloid proteins are produced and amyloid deposits build up within an organ, they can prevent that organ from working correctly. The organ can become damaged, leading to disease symptoms and eventually, organ failure.
Experts believe there are a couple of reasons amyloid deposits cause damage:
There are different types of amyloidosis. Some types are localized, meaning amyloid deposits are only found in one location in the body. Other types are systemic and cause amyloid proteins to build up in many areas.
AL amyloidosis is the most common type of systemic amyloidosis. In this subtype, plasma cells — a type of white blood cell — make misshapen light-chain proteins. Light chains are used to form antibodies, immune proteins that kill germs and fight infections. Although plasma cells are usually found in the bone marrow tissue located inside of certain bones, the amyloid light-chain proteins they produce can spread throughout the body.
Read about the connection between AL amyloidosis and blood cancers, such as multiple myeloma.
The symptoms you have may provide a clue as to which organs are affected. To determine whether AL amyloidosis is damaging a particular organ, your doctor may recommend a biopsy. During this procedure, a small sample of the organ will be removed and sent to a lab. There, specialists will stain the tissue with a dye called Congo red. The sample will turn green if amyloid proteins are present within that organ. Knowing which organs may be damaged may help you and your health care team understand how to treat your condition and what your prognosis might be.
Read about staging and progression in AL amyloidosis.
As many as 3 out of 4 people with AL amyloidosis develop amyloid proteins in the muscle tissue of their hearts. This is sometimes referred to as cardiac amyloidosis. When amyloid fibrils collect in the heart, the walls of this organ become thicker, which can lead to heart failure. Common symptoms that may indicate heart damage include:
The main factor that determines a person’s AL amyloidosis prognosis is whether the disease affects the heart. Past studies have found that those who have heart failure due to AL amyloidosis live for an average of six months after diagnosis, if the disease is left untreated. However, newer treatments may be improving survival rates. For example, receiving a heart transplant often leads to better outcomes. Studies show that:
Not everyone is healthy enough to undergo a heart transplant, but other treatments can also help. Abnormal heart rhythms can be treated with a pacemaker device that helps the heart beat more regularly. Additionally, treatments designed to kill abnormal plasma cells, including drugs like Darzalex (daratumumab) and Velcade (bortezomib), can reduce levels of light-chain proteins. This can improve cardiac symptoms for people with AL amyloidosis, often leading to a better outcome.
AL amyloidosis affects the kidneys in about 65 percent of cases. It often causes a condition called nephrotic syndrome. Nephrotic syndrome can lead to signs like high levels of protein in the urine, low levels of albumin protein in the blood, or high cholesterol levels. Eventually, nephrotic syndrome can lead to kidney failure.
If you have amyloid deposits in the kidneys, you may experience symptoms like:
Treatments that target plasma cells and eliminate amyloid proteins can also help improve kidney function. One common treatment for AL amyloidosis is a high-dose chemotherapy drug called Evomela (melphalan) followed by an autologous stem cell transplant. During a stem cell transplant, a person receives healthy blood stem cells that can make new plasma cells to replace the abnormal ones. This process can sometimes help decrease signs of kidney disease. People who have improved kidney function following this treatment are more likely to live longer. Other treatments, such as dialysis and kidney transplant, may also be used to help people with AL amyloidosis who experience kidney failure.
In a small study of 43 people with AL amyloidosis, 35 percent had nervous system involvement. Amyloid deposits can damage nerves in the arms, hands, feet, or legs. AL amyloidosis can also affect the nerves that control body functions like blood pressure or movement of food through the intestines.
People with nervous system damage may experience:
These symptoms might go away if you are treated for AL amyloidosis. However, many people continue to have nerve-related symptoms even after their treatment is finished. Nervous system symptoms can also be caused by chemotherapy drugs used to treat AL amyloidosis. However, treatment-related symptoms will usually disappear once you are no longer using these medications.
Experts estimate that between 1 percent and 8 percent of AL amyloidosis cases affect the gastrointestinal (digestive) system. Amyloidosis can affect the tongue, esophagus, stomach, small intestines, large intestines, liver, or some combination of these. Deposits can form in the muscle, mucus membrane, nerves, or blood vessels of these organs, leading to a wide variety of symptoms.
These symptoms can include:
One study of 137 people with AL amyloidosis found that those with gastrointestinal amyloidosis symptoms lived for an average of about eight months following diagnosis. People without these symptoms lived for an average of nearly 16 months. However, chemotherapy and stem cell transplantation has been found to improve amyloidosis and help people with digestive AL amyloidosis live longer.
Amyloid deposits can be found in the skin of about 30 percent to 40 percent of people with AL amyloidosis. Skin-related symptoms can include:
Skin treatments may include surgery to remove the bumps. However, skin symptoms often don’t have as big of an impact on overall health compared with symptoms related to other organs. Heart and kidney function play the biggest role in a person’s prognosis.
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