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diabetes mellitus
(di″ә-beītēs melīĭ-tәs)
a broadly applied term that refers to a complex group of syndromes having in common a disturbance in the oxidation and use
of glucose. This is often secondary to a malfunction of the beta cells of the pancreas, whose function is the production and release of insulin. Because insulin is involved in the metabolism of carbohydrates, proteins, and fats, diabetes is not limited to a disturbance of glucose homeostasis alone. Most cases of diabetes mellitus fall into two broad categories, called type 1 and type 2 diabetes mellitus There are also other types, such as gestational diabetes mellitus and impaired glucose homeostasis. Diabetes mellitus can present a wide variety of symptoms, from none at all to profound ketosis and coma. If it first appears late in life, patients may not know they have it until it is discovered during a routine examination,
or when the symptoms of chronic vascular disease, gradual kidney failure, or impaired vision cause them to seek medical help.
The typical symptoms are increased urination, increased thirst, and increased hunger. Because of insulin deficiency, glucose
accumulates in the blood, which increases the blood osmolarity and osmotic pressure; this causes depletion of intracellular water and diuresis. The water loss creates intense thirst and increased urination. The noticeable increase in appetite is not as clearly understood; it may be the result of the body's effort to increase
its supply of energy foods even though eating more carbohydrates in the absence of sufficient insulin does not meet the energy needs of the cells.
Copyright 2007. An Elsevier publication. All rights reserved.
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