Amyloidosis is a rare, chronic disease resulting in the accumulation of an abnormal fibrillar scleroprotein (amyloid), which infiltrates body organs and soft tissues. Amyloidosis is classified in two ways, based on histologic findings: perireticular type, which affects the inner coats of blood vessels, and pericollagen type, which affects the outer coats of blood vessels and also involves the parenchyma.
Although prognosis varies with type and with the site and extent of involvement, amyloidosis sometimes results in permanent — usually life-threatening — organ damage.
Amyloidosis is sometimes familial, especially in people of Portuguese ancestry. It may occur in conjunction with tuberculosis, chronic infection, rheumatoid arthritis, multiple myeloma, Hodgkin’s disease, paraplegia, and brucellosis. It may also accompany Alzheimer’s disease.
In amyloidosis, accumulation and infiltration of amyloid produces pressure and causes atrophy of nearby cells. Reticuloendothelial cell dysfunction and abnormal immunoglobulin synthesis occur in some types of amyloidosis. In the United States, evidence of amyloidosis on autopsy is 0.5%, but true incidence is difficult to determine.
Amyloidosis produces dysfunction of the kidneys, heart, GI tract, peripheral nerves, and liver.
❑ Kidneys: The primary sign of renal involvement is proteinuria, leading to nephrotic syndrome and, eventually, renal failure.
❑ Heart: Amyloidosis often causes intractable heart failure, due to amyloid deposits in the subendocardium, endocardium, and myocardium.
❑ GI tract: GI amyloidosis may produce stiffness and enlargement of the tongue, hindering enunciation. In addition, it may decrease intestinal motility and produce malabsorption, bleeding, infiltration of blood vessel walls, abdominal pain, constipation, and diarrhea. Tumorlike amyloid deposits may occur in all portions of this system. Chronic malabsorption may lead to malnutrition and predispose to infection.
❑ Peripheral nervous system: The appearance of peripheral neuropathy indicates peripheral nerve involvement.
❑ Liver: Hepatic amyloidosis is rare and usually coexists with other forms of this disease. It generally produces liver enlargement, often with azotemia, anemia, albuminuria and, rarely, jaundice.
In cardiac amyloidosis, other findings include faint heart sounds and an electrocardiogram showing low voltage and conduction or rhythm abnormalities resembling those characteristic of myocardial infarction. In hepatic amyloidosis, liver function studies are generally normal, except for a slightly elevated serum alkaline phosphatase level.
Treatment is directed at eliminating the underlying cause and is mainly supportive. Transplantation may be useful for amyloidosis-induced renal failure, although the donor kidney may also develop amyloidosis. Patients with cardiac amyloidosis require conservative treatment to prevent dangerous arrhythmias. Malnutrition caused by malabsorption in end-stage GI involvement may require total parenteral nutrition.
❑ Maintain nutrition and fluid balance; give analgesics to relieve intestinal pain; control constipation or diarrhea; and manage infection and fever.
❑ Provide good mouth care for the patient with tongue involvement. Refer him for speech therapy if needed; provide an alternate method of communication if he can’t talk.
❑ Regularly assess airway patency when the tongue is involved and prevent respiratory tract compromise by gentle and adequate suctioning, when indicated. Keep a tracheostomy tray at the bedside.
❑ When long-term bed rest is necessary, properly position the patient and turn him often to prevent pressure ulcers. Perform range-of-motion exercises to prevent contractures.
❑ Provide psychological support. Exercise patience and understanding to help the patient cope with this chronic illness.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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Title: Professional Guide to Diseases (Eighth Edition)
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2005
ISBN: 1-58255-370-X
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