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Amyloidosis

A Primary or Secondary Disorder Occurring in Other Conditions

Aug 5, 2007 Elaine Moore

Amyloidosis is characterized by deposits of amyloid protein within one or more organs. Amyloidosis can occur as an autoimmune disorder or it can accompany other disorders

Amyloidosis is a disorder in which deposits of an abnormal protein known as amyloid protein accumulate in one or more organs. These deposits interfere with the normal functioning of affected organs. Amyloidosis may occur as a primary autoimmune disorder or it may occur as a secondary condition accompanying rheumatoid arthritis, inflammatory bowel disease, ankylosing spondylitis, Behcet syndrome, psoriasis and psoriatic arthritis, infections such as tuberculosis, inflammatory diseases, some cancers, and Mediterranean fever. In autoimmune amyloidosis, plasma cells in the bone marrow produce abnormal antibodies made from amyloid protein.

In addition to autoimmune amyloidosis, conditions of amyloidosis may occur as a familial or hereditary disorder caused by a protein mutation or it may occur as a manifestation of beta 2 micro globulin disorders, which can occur in people undergoing dialysis, and it can occur in Alzheimer’s disease as amyloid deposits lodge within brain cells.

Who is Affected?

While the condition known as amyloidosis has been reported for more than 300 years, it’s only been in the last 20 years that researchers discovered the protein abnormalities that characterize amyloidosis. People with a family history of amyloidosis and people with autoimmune disorders are at risk for amyloidosis.

What is Amyloid Protein?

The body produces nearly 25 different types of amyloid protein. Amyloid protein production is caused by the aggregation of misfolded, normally soluble proteins. Amyloid protein forms fibers or fibrils that lodge in organs and tissues.

Symptoms of Amyloidosis

Symptoms depend on the affected organs. The organs most often affected include the kidneys, liver, spleen, heart, tongue, intestines, skeletal and smooth muscles, nerves, skin, and ligaments.

Common symptoms include enlarged tongue, fatigue, irregular hear rhythm, numbness of hands and feet, shortness of breath, skin changes, difficulty swallowing, weak hand grip, weight loss, hoarseness or voice changes, other tongue problems, weakness, diarrhea, and decreased urine output. When there is systemic involvement, amyloidosis can be fatal.

Conditions that can occur as a result of amyloidosis include

Malabsorption of nutrients
Kidney failure
Respiratory failure
Gastrointestinal reflux disease
Carpal tunnel syndrome
Cardiomyopathy, heart failure
Endocrine failure
Death

Diagnosis

Diagnosis depends on the organ or organs affected. An abdominal ultrasound may reveal an enlarged liver or spleen. Biopsy of tissue or organs will be positive for amyloid deposits. A bone marrow showing the presence of abnormal plasma cells can also confirm the diagnosis. Nerve conduction velocity tests can show a conduction block. Kidney function tests show abnormalities when the kidneys are affected.

Treatment

Some patients respond to chemotherapeutic agents such as methotrexate directed at the abnormal plasma cells. In amyloidosis that accompanies another inflammatory disorder such as rheumatoid arthritis, treatment aimed at reducing inflammation can improve symptoms or slow disease progression. Diets that work to reduce inflammation also offer benefits.

Resources:

Primary Amyloidosis, Medline Plus Encyclopedia, National Institutes of Health, July 10, 2007, accessed July 20, 2007.

Bruce Baethge, Amyloidosis, Overview, eMedicine from WebMD, Aug 11, 2006,

The copyright of the article Amyloidosis in General Medicine is owned by Elaine Moore. Permission to republish Amyloidosis in print or online must be granted by the author in writing.

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