A disorder in which insoluble protein fibers are deposited in tissues and organs, impairing their function.

Alternative Names

Amyloid - primary

Causes, incidence, and risk factors

The cause of primary amyloidosis is unknown, but the condition is related to abnormal production of immunoglobulins by plasma cells (a type of immune cell). Symptoms are related to the organs affected by the deposits, which can include the following: tongue, intestines, skeletal and smooth muscles, nerves, skin, ligaments, heart, liver, spleen, and kidneys. Cardiomyopathy (decreased heart function), renal failure (kidney failure), carpal tunnel syndrome (painful swelling of nerves in the wrist), malabsorption (inadequate absorption of nutrients from the intestinal tract), gastrointestinal reflux, and other conditions can result. The deposits infiltrate the affected organs, causing them to lose resilience and become stiff, which decreases their ability to function. Secondary amyloidosis can be caused by infection, inflammatory diseases, and sometimes cancer. Risk factors have not been identified. Primary amyloidosis is rare, occurring only in 1 out of 100,000 people.

Signs and tests

A

physical examination may show enlarged liver or spleen. There may be signs of heart failure . If specific organ damage is suspected, testing to confirm amyloidosis of that organ may be performed.

biopsy

of a tissue or organ will be positive for amyloid. A

skin biopsy that includes subcutaneous fat, a rectal mucosa biopsy, or a bone marrow biopsy can help confirm the diagnosis.

heart evaluation may reveal

arrhythmias , abnormal heart sounds , or signs of heart failure.

ECG

shows abnormalities.

echocardiogram

shows poor wall motion because of a stiff heart

muscle ( cardiomyopathy ).

kidney function

evaluation may reveal renal failure or nephrotic syndrome (excessive protein in the urine).

Urinalysis

shows

protein , casts , or fat bodies.

Serum creatinine

is increased.

BUN

is increased.

abdominal ultrasound

may reveal enlarged liver or spleen.

evaluation for

carpal tunnel syndrome may reveal involvement of the nerve:

Nerve conduction velocity

shows a conduction block.

Hand grips are weak because of

weakness of the thumb. This disease may also alter the results of the following tests:

tongue biopsy

nerve biopsy

myocardial biopsy

gum biopsy

carpal tunnel biopsy

Bence-Jones protein (quantitative)

immunoelectrophoresis - serum

quantitative immunoglobulins

urine

protein

Treatment

Some patients with primary amyloidosis respond to chemotherapy directed at the abnormal plasma cells. In secondary amyloidosis, aggressive treatment of the underlying disease can improve symptoms and/or slow progression of disease. Complications such as heart failure, kidney failure , and other problems can sometimes be treated as necessary.

Expectations (prognosis)

The severity of the disease depends upon the organs affected. Heart and kidney involvement may lead to organ failure and death. Systemic involvement is associated with death within 1 to 3 years.

Complications

heart failure

kidney failure

endocrine

failure (hormonal disorder)

respiratory

failure

death

Calling your health care provider

Call your health care provider if symptoms consistent with primary amyloidosis develop. If you know you have primary amyloidosis, call your health care provider if difficulty breathing , persistent swelling of the ankles or other areas, decreased urine output , or other symptoms occur. This may indicate that complications have developed.

Prevention

There is no known prevention.