amyloidosis

More about Amyloidosis: Causes and symptoms Diagnosis Treatment Prognosis Prevention Resources

Definition

Amyloidosis is a progressive, incurable, metabolic disease characterized by abnormal deposits of protein in one or more organs or body systems.

Description

Amyloid proteins are manufactured by malfunctioning bone marrow. Amyloidosis, which occurs when accumulated amyloid deposits impair normal body function, can cause organ failure or death. It is a rare disease, occurring in about eight of every 1, 000, 000 people. It affects males and females equally and usually develops after the age of 40. At least 15 types of amyloidosis have been identified. Each one is associated with deposits of a different kind of protein.

Types of amyloidosis

The major forms of this disease are primary systemic, secondary, and familial or hereditary amyloidosis. There is also another form of amyloidosis associated with Alzheimer's disease.

Primary systemic amyloidosis usually develops between the ages of 50 and 60. With about 2, 000 new cases diagnosed annually, primary systemic amyloidosis is the most common form of this disease in the United States. Also known as light-chain-related amyloidosis, it may also occur in association with multiple myeloma (bone marrow cancer).

Secondary amyloidosis is a result of chronic infection or inflammatory disease. It is often associated with:

• familial Mediterranean fever (a bacterial infection characterized by chills, weakness, headache, and recurring fever)
• granulomatous ileitis (inflammation of the small intestine)
• Hodgkin's disease (cancer of the lymphatic system)
• leprosy
• osteomyelitits (bacterial infection of bone and bone marrow)
• rheumatoid arthritis

Familial or hereditary amyloidosis is the only inherited form of the disease. It occurs in members of most ethnic groups, and each family has a distinctive pattern of symptoms and organ involvement. Hereditary amyloidosis is though to be autosomal dominant, which means that only one copy of the defective gene is necessary to cause the disease. A child of a parent with familial amyloidosis has a 50-50 chance of developing the disease.

Amyloidosis can involve any organ or system in the body. The heart, kidneys, gastrointestinal system, and nervous system are affected most often. Other common sites of amyloid accumulation include the brain, joints, liver, spleen, pancreas, respiratory system, and skin.

— Maureen Haggerty

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n.
A disorder marked by the deposition of amyloid in various organs and tissues of the body. It may be associated with a chronic disease such as rheumatoid arthritis, tuberculosis, or multiple myeloma.

A disorder characterized by the accumulation of an unusual extracellular fibrous protein (amyloid) in the connective tissue of the body. The deposition of amyloid may be widespread, involving major organs and leading to serious clinical consequences, or it may be very limited with little effect on health.

Amyloidosis has been classified clinically as: (1) primary amy-loidosis, with no evidence for preexisting or coexisting disease; (2) amyloidosis associated with multiple myeloma; (3) secondary amyloidosis, associated with chronic infections (such as osteomyelitis, tuberculosis, leprosy), chronic inflammatory disease (such as rheumatoid arthritis, ankylosing spondylitis, regional enteritis), or neoplasms (such as medullary carcinoma of the thyroid); (4) heredofamilial amyloidosis, associated with familial Mediterranean fever and a variety of heritable neuropathic, renal, cardiovascular, and other syndromes; (5) local amyloidosis, with local, often tumorlike, deposits in isolated organs without evidence of systemic involvement; (6) amyloidosis associated with aging. There is no specific treatment for amyloidosis, but supportive treatment is very useful.

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(am′iloidō′sis)
n

A condition in which amyloid, a glyco-protein, is deposited intercellularly in tissues and organs. Four types of amyloidosis are recognized, two of which, primary amyloidosis and amyloid tumor, frequently produce nodules in the tongue and gingiva.

Amyloidosis. (Regezi/Sciubba/Jordan, 2003)

The deposition in various tissues of amyloid. This protein is almost insoluble and once it infiltrates the tissues they become waxy and nonfunctioning. Systemic amyloidosis may be immunocytic or reactive (see below).

• cutaneous a. — multiple cutaneous, hard, painless, chronic plaques occur over the head, neck and shoulders of horses. There may be involvement of the nasal mucosa and resulting dyspnea.
• familial renal a. of Shar pei dogs — manifested by episodic fever and swelling of one or both hocks which may resolve spontaneously, but is recurring. The condition is resistant to treatment and eventually there is renal and/or hepatic failure.
• immunocytic a., immunogenic a., primary a. — amyloid produced from light chains of immunoglobulins as in plasma-cell dyscrasias. See also al protein.
• reactive a. — is derived from excess serum protein SAA produced as a result of chronic antigenic stimulation. The kidney is most often affected and the amyloid is most often deposited in glomeruli but medullary deposits are seen in cats and cattle. Idiopathic amyloidosis is common in the dog and less common in cats. It is associated with chronic suppurative disease processes in cattle, antiserum production in horses, and it occurs rarely in pigs. Called also secondary alopecia.
• renal a. — characterized by severe proteinuria and uremia. There is chronic diarrhea, polydipsia and anasarca. Seen particularly in dogs and cats.
• secondary a. — reactive amyloidosis (above).