19 WEIGHT LOSS
Harrison’s Manual of Medicine
Significant unintentional weight loss in a previously healthy individual is often a harbinger of underlying systemic disease. The routine medical history should always include inquiry about changes in weight. Rapid fluctuations of weight over days suggest loss or gain of fluid, whereas long-term changes usually involve loss of tissue mass. Loss of 5% of body weight over 6-12 months should prompt further evaluation.
A list of possible causes of weight loss is extensive (Table 19-1). In older persons the most common causes of weight loss are depression, cancer, and benign gastrointestinal disease. In younger individuals diabetes mellitus, hyperthyroidism, anorexia nervosa, and infection, especially with HIV, should be considered.
Table 19-1 Causes of Weight Loss
Before extensive evaluation is undertaken, it is important to confirm that weight loss has occurred. In the absence of documentation, changes in belt notch size or the fit of clothing may help to determine loss of weight.
The history should include questions about fever, pain, shortness of breath or cough, palpitations, and evidence of neurologic disease. A history of GI symptoms should be obtained, including difficulty eating, dysphagia, anorexia, nausea, and change in bowel habits. Use of cigarettes, alcohol, and all medications should be reviewed, and patients should be questioned about previous illness or surgery as well as diseases in family members. Risk factors for HIV should be assessed. Signs of depression, evidence of dementia, and social factors, including financial issues that might affect food intake, should be considered.
Physical examination should begin with weight determination and documentation of vital signs. The skin should be examined for pallor, jaundice, turgor, surgical scars, and stigmata of systemic disease. Evaluation for oral thrush, dental disease, thyroid gland enlargement, and adenopathy and for respiratory, cardiac, or abdominal abnormalities should be performed. All men should have a rectal examination, including the prostate; all women should have a pelvic examination; and both should have testing of the stool for occult blood. Neurologic examination should include mental status assessment and screening for depression.
Initial laboratory evaluation is shown in Table 19-2, with appropriate treatment based on the underlying cause of the weight loss. If an etiology of weight loss is not found, careful clinical follow-up, rather than persistent undirected testing, is reasonable.
Table 19-2 Screening Tests for Evaluation of Involuntary Weight Loss
For a more detailed discussion, see Reife CM: Weight Loss, Chap. 43, p. 250, in HPIM-15.