Sunday, January 15, 2006

vitamin B12 deficiency (pernicious anemia)

Pernicious anemia is the most common type of megaloblastic (abnormal blood cells) anemia. It is caused by a vitamin B12 deficiency secondary to the lack of intrinsic factor secretion due to gastric atrophy. It occurs most frequently in later life. The onset is insidious so that the anemia may be severe by the time the patient is first seen. The symptoms often can be mistaken for other illnesses, especially in the elderly. Inflammation of the tongue is an important sign. Liver enlargement is common, especially if there is cardiac failure, and mental changes seem to predominate. Other symptoms include anorexia (loss of appetite), nausea, vomiting, flatulence, dyspepsia (discomfort under the breastbone after eating), and diarrhea.
Pernicious anemia may occur over a period of eight to 12 years in patients who have had a partial gastrectomy (surgical removal of all or part of the stomach). After a total gastrectomy, B12 stores are depleted in two to three years and pernicious anemia follows about nine months later.
Vitamin B12 therapy is necessary for life in confirmed cases of pernicious anemia. In the elderly, this is administered by injection and rarely by oral therapy. Clinical improvement is observed almost immediately after the start of therapy. However, neurological symptoms are slower to respond unless they have been present for less than six months.
Ham, R. J. Geriatric Medicine Annual-1987. Oradell, N.J.: Medical Economics Books, 1987.
Reichel. W. Clinical Aspects of Aging. Baltimore: Williams & Wilkins Co., 1979.

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