A disorder in which insoluble protein fibers are deposited in
tissues and organs, impairing their function.
Causes of Amyloidosis
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.
Symptoms of amyloidosis
- numbness of hands and feet
- weak hand grip
- weight loss
- shortness of breath
- swelling of the extremities
- swallowing difficulties
- irregular heart rhythm
- skin changes
- enlarged tongue
Additional symptoms that may be associated with this disease:
- urine output, decreased
- other tongue problems
- stools, clay colored
- joint pain
- hoarseness or changing voice
Diagnosis of amyloidosis
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
- 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
- heart evaluation may reveal arrhythmias, abnormal heart sounds, or signs of heart
- 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 of amyloidosis
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.
Information compiled from the National Institutes of Health
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