Amyloid - primary

Definition

Primary amyloidosis is a disorder in which protein fibers are deposited in tissues and organs, harming them.

Alternative Names

Causes

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

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

Primary amyloidosis can result in conditions that include:

• Cardiomyopathy
• Carpal tunnel syndrome
• Gastrointestinal reflux (GERD)
• Kidney failure
• Malabsorption

The deposits invade the affected organs, causing them to 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

• Enlarged tongue
• Fatigue
• Irregular heart rhythm
• Numbness of hands and feet
• Shortness of breath
• Skin changes
• Swallowing difficulties
• Swelling in the arms and legs
• Weak hand grip
• Weight loss

Additional symptoms that may be associated with this disease:

• Clay-colored stools
• Decreased urine output
• Diarrhea
• Hoarseness or changing voice
• Joint pain
• Other tongue problems
• Weakness

Exams and Tests

Your doctor may discover that you have an enlarged liver or spleen. You may also have signs of heart failure

If specific organ damage is suspected, your doctor may order tests to confirm amyloidosis of that organ. For example:

• Abdominal ultrasound may reveal enlarged liver or spleen.
• A 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.
• A heart evaluation may reveal arrhythmias, abnormal heart sounds, or signs of heart failure.
  • An ECG shows abnormalities.
  • An echocardiogram shows poor motion of the heart wall, due to a stiff heart muscle (cardiomyopathy).
• Evaluation for carpal tunnel syndrome may reveal involvement of the nerve:
  • Hand grips are weak because of weakness of the thumb.
  • Nerve conduction velocity shows a conduction block.
• Kidney function evaluation may reveal kidney failure or nephrotic syndrome (too much protein in the urine).
  • BUN is increased.
  • Serum creatinine is increased.
  • Urinalysis shows protein, casts, or fat bodies.

This disease may also alter the results of the following tests:

• Bence-Jones protein (quantitative)
• Carpal tunnel biopsy
• Gum biopsy
• Immunoelectrophoresis - serum
• Myocardial biopsy
• Nerve biopsy
• Quantitative immunoglobulins
• Tongue biopsy
• Urine protein

Treatment

Some patients with primary amyloidosis respond to chemotherapy directed at the abnormal plasma cells. Stem cell transplantation 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.

Outlook (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.

Possible Complications

• Death
• Endocrine failure (hormonal disorder)
• Heart failure
• Kidney failure
• Respiratory failure

When to Contact a Medical Professional

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.

Buxbaum JN. The Amyloidoses. In: Goldman L, Ausiello D. Cecil Textbook of Medicine. 22nd ed. Philadelphia, Pa: WB Saunders; 2004.

Hoffman R, Benz Jr. EJ, Shattil SJ, et al., eds. Hematology: Basic Principles and Practice. 4th ed. Philladelphia, Pa: Churchill Livingston; 2005:1540-48.