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endocrine system
obesity
diagnoses
definition and etiology
definition: Body weight over 20% of the normal weight for the patient based on standard height/weight charts. Except for persons who are heavily muscular, the 20% figure is usually accurate.
etiology: Conventionally, the principal cause of obesity is ingestion of calories beyond the body's energy output. The stored energy is deposited in adipose tissue.
The three major components of overall energy usage are resting metabolic rate (approximately 60-75% of daily caloric burning); caloric expenditure through exercising; and the thermic response to eating food (burning energy to digest, absorb, and process).
There are seven factors involved in a person becoming and remaining overweight:
genetic: Obesity tends to be familial. Statistics are that 80% of the offspring of two obese parents are overweight; 40% of the offspring of one obese parent; while only 10% of the offspring of normal parents are overweight. It is not clear whether the principal cause is purely genetic, or a combination of familial eating patterns, environmental factors and genetics.
psychologic: Although many obese patients admit they overeat when emotionally upset, there is no clear understanding, in conventional medicine, of the physiologic connections between mood and overeating. Specific psychologic disorders associated with obesity are bulimia and night-eating syndrome.
endocrine: Endocrine disorders are usually secondary to obesity and not primary causes for patients becoming overweight. Apparently the only true endocrine disorder which causes obesity is hyperadrenocorticism, although hypothyroidism can clearly lower the metabolism enough to cause weight gain and prevent weight loss.
physical activity: The sedentary lifestyle of Western societies is frequently recognized as a major reason for the obesity seen in those societies. Physical activity not only burns calories directly, but increases the metabolism between exercise periods, leading to a generally higher use of calories.
social factors: These factors are gaining importance as key determinants of obesity. Obesity is seen significantly more in low socioeconomic groups than higher ones.
developmental: There are three types of obesity on the cellular level:
» hypertrophic (increase in fat cell size: seen in adult-onset obesity)
» hyperplastic (increase in amount of fat cells: seen in childhood-induced obesity)
» hypertrophic-hyperplastic, which is a combination of the two, often seen in childhood-onset obesity; as the obese child ages, s/he must severely limit the amount of adipose in each cell to maintain a normal weight because they have developed so many more fat cells than normal.
Obesity is also generally associated with aging, as often the caloric intake remains as it did when the patient was younger, though their metabolism and physical activity slows.
brain damage: Brain damage may cause obesity, though the reports are extremely rare in humans.
signs and symptoms
20% above weight for age and height.
Signs and symptoms associated with the primary cause for obesity, if there is one: e.g. buffalo hump in Cushing's.
Hypoventilation syndrome (Pickwickian syndrome).
lab findings:
May have elevated lipids, glucose.
Rule out thyroid disease, adrenal disease with appropriate testing.
Hormonal assays if indicated.
Consider other testing for primary causes of obesity.
course and prognosis
Obesity increases morbidity and mortality, usually from cardiovascular system disorders (atherosclerosis, hyperlipidemia, hypertension).
Other illnesses associated with the obese include hypoglycemia and hyperglycemia, low self-esteem and dislike of self and body, and anxiety and depression over inability to lose weight. Weight-loss programs are notoriously ineffective in treatment of the obese, and so the prognosis is very poor, especially for obese children.
Conventional treatment consists of a low calorie diet; therapeutic fasting; medication to decrease the appetite or to increase the metabolism through the thyroid; exercise; surgery only in those to whom all other treatments have failed (jejunoileal bypass, gastric bypass, gastric stapling); behavior modification and self-help groups.
Holistic approaches involving metabolic enhancement, lifestyle counseling, dietary modifications and exercise programs are usually effective where compliance is maintained, and where pathological abnormalities are absent.
differential diagnosis
Cushing's disease.
Hypothyroidism.
Insulinoma.
Hypothalamic disorders.
footnotes