Primary amyloidosis

Definition

Primary amyloidosis is a disorder in which insoluble protein fibers are deposited in tissues and organs, impairing their function.

Causes, incidence, and risk factors

The cause of primary amyloidosis is unknown, but the condition is related to abnormal production of immunoglobulins by a type of immune cell called plasma cells.

The symptoms depend on the organs affected by the deposits, which can include the tongue, intestines, skeletal and smooth muscles, nerves, skin, ligaments, heart, liver, spleen, and kidneys.

This can result in the following conditions:

• Cardiomyopathy (poor heart function)
• Kidney failure
• Carpal tunnel syndrome (painful swelling of nerves in the wrist)
• Malabsorption (inadequate absorption of nutrients from the intestinal tract)
• Gastrointestinal reflux (GERD)
• Other conditions

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. It is related to the malignant plasma cell disorder multiple myeloma.

Symptoms

• fatigue
• 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

• weakness
• urine output, decreased
• other tongue problems
• stools, clay colored
• diarrhea
• joint pain
• hoarseness or changing voice

Signs and tests

Your doctor may discover that you have an 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. For example:

• 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. Autologous stem cell transplanation may be used, as in multiple myeloma.

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.

Illustrations

Amyloidosis on the fingers

Amyloidosis on the face

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Amyloid - primary