Primary amyloidosis

Definition

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

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 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:

• Carpal tunnel syndrome
• Gastrointestinal reflux (GERD)
• Heart muscle damage (cardiomyopathy)
• Kidney failure
• Malabsorption

The deposits build up in the affected organs, causing them to become stiff, which decreases their ability to function.

Risk factors have not been identified. Primary amyloidosis is rare. It is similar to multiple myeloma, and is treated the same way.

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

Signs and tests

Your doctor may discover that you have an enlarged liver or spleen.

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

• Abdominal ultrasound may reveal a swollen liver or spleen.
• An abdominal fat pad biopsy, rectal mucosa biopsy, or a bone marrow biopsy can help confirm the diagnosis.
• A heart evaluation, including an ECG,may reveal arrhythmias, abnormal heart sounds, or signs of congestive heart failure. An echocardiogram shows poor motion of the heart wall, due to a stiff heart muscle.
• A carpal tunnel syndrome evaluation may show that hand grips are weak.Nerve conduction velocity shows abnormalities.
• Kidney function tests may show signs of kidney failure or too much protein in the urine ( nephrotic syndrome).
  • BUN level 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.

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

• Congestive heart failure
• Death
• Endocrine failure (hormonal disorder)
• Kidney failure
• Respiratory failure

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.

References

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.