Amyloidosis can affect different organs

By The staff at the Mayo Clinic

Amyloidosis (am-uh-loi-DO-sis) is a disease that occurs when substances called amyloid proteins build up in your organs. Amyloid is an abnormal protein usually produced by cells in your bone marrow that can be deposited in any tissue or organ.

Amyloidosis can affect different organs in different people, and there are different types of amyloid. Amyloidosis frequently affects the heart, kidneys, liver, spleen, nervous system and gastrointestinal tract.

Signs and symptoms of amyloidosis depend on which of your organs are affected. When signs and symptoms are evident, they may include:

• Swelling of your ankles and legs
• Weakness
• Significant weight loss
• Shortness of breath
• Numbness or tingling in your hands or feet
• Diarrhea or constipation
• Feeling full quickly
• Severe fatigue
• An enlarged tongue (macroglossia)
• Skin changes, such as thickening or easy bruising
• Purplish patches (purpura) around the eyes
• An irregular heartbeat
• Difficulty swallowing
• Protein in the urine (detected by urine tests)

Doctors classify amyloidosis into three major forms:

• Primary amyloidosis. This most common form of amyloidosis can affect many areas, including your heart, kidneys, liver, spleen, nerves, intestines, skin, tongue and blood vessels. Primary amyloidosis isn’t associated with other diseases — except for multiple myeloma, a form of bone marrow cancer.The exact cause of primary amyloidosis is unknown, but doctors do know that the disease begins in your bone marrow. In addition to producing red and white blood cells and platelets, your bone marrow makes antibodies — proteins that protect you against infection and disease. After antibodies serve their function, your body breaks them down and recycles them. Amyloidosis occurs when cells in the bone marrow produce antibodies that can’t be broken down. These antibodies then build up in your bloodstream. Ultimately, they leave your bloodstream and can deposit in your tissues as amyloid, interfering with normal function.

• Secondary amyloidosis. This form occurs in association with chronic infectious or inflammatory diseases, such as tuberculosis, inflammatory arthritis or osteomyelitis, a bone infection. It primarily affects your kidneys, spleen, liver and lymph nodes, though other organs may be involved. Treatment of the underlying disease may help stop progression of this form of amyloidosis.

• Hereditary (familial) amyloidosis. As the name implies, this form of amyloidosis is inherited. This type often affects the liver, nerves, heart and kidneys.

• Dialysis-related amyloidosis (DRA). This form of amyloidosis develops when proteins in blood are deposited in joints and tendons, causing pain, stiffness and fluid in the joints, as well as carpal tunnel syndrome. The condition is most likely to affect people on long-term hemodialysis.

Risk factors

Anyone can develop primary amyloidosis, but certain factors place you at greater risk:

• Age. The majority of people who develop amyloidosis are older than 60.

• Other diseases. You may be at increased risk if you have a chronic infectious or inflammatory disease. People who have multiple myeloma — a form of bone marrow cancer — are also at increased risk of amyloidosis.

• Family history. Some cases of amyloidosis are inherited.

• Kidney dialysis. If you have kidney disease requiring kidney dialysis, you have an increased risk of dialysis-associated amyloidosis. This is because dialysis can’t remove large proteins from the blood, so large, abnormal proteins may build up and deposit in surrounding tissues. This condition is less common with modern dialysis techniques.

Complications

The severity of amyloidosis depends on which organs the amyloid deposits affect. Potentially life-threatening situations include kidney failure and congestive heart failure:

• Kidney damage. When amyloidosis affects your kidneys, their filtering system is damaged, sometimes causing protein to leak from your blood into your urine. Ultimately, damage to the kidneys’ filtering system inhibits your kidneys’ ability to remove waste products from your body, which may progress to kidney failure.

• Heart damage. When amyloidosis affects your heart, a common symptom is shortness of breath, even with slight exertion. You may find it difficult to climb a flight of stairs or walk long distances without stopping to rest. When amyloid protein builds up in your heart, it reduces your heart’s ability to fill with blood in between heartbeats. This means less blood is pumped with each beat. Your heart will have difficulty keeping up with your body’s demand for blood during exertion. And when amyloidosis affects the electrical system of your heart, this may disturb your heart’s rhythm.

• Nervous system damage. Another potential complication of amyloidosis is disruption of your nervous system function. This may include carpal tunnel syndrome — characterized by pain, numbness or tingling of the fingers. Disruption of another area of your nervous system might cause numbness or a lack of feeling in your toes or soles of your feet, or a burning sensation in these areas.If amyloid deposits affect the nerves that control your bowel function, you may experience periods of alternating constipation and diarrhea. Sometimes the condition affects nerves that control blood pressure, and you may experience dizziness or near fainting when standing too quickly as a result of a drop in your blood pressure.

This article was originally published here:
http://www.mayoclinic.org