Weight Loss
Weight Loss: Excerpt from The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
David B. Graham
Involuntary weight loss is a challenging problem, often surrounded with fears by both patient and physician of an occult malignancy. Although malignancy is an important cause of weight loss, extensive and costly workups for occult cancers are rarely beneficial (1–5). The evaluation of weight loss is accomplished through simple and concise history, physical examination, and laboratory testing.
Approach.
The key to the diagnosis of involuntary weight loss is a careful and complete history and physical examination. The approach begins broadly and then quickly focuses on specifics derived from the initial evaluation.
A. Quantify loss. A loss of 5% of the baseline body weight (not ideal body weight) over 6 months is significant (1–3,5).
1. Can the weight loss be verified? Serial measurements are best, but other markers include numerical estimates and changes in clothing or belt size.
2. Up to 50% of patients do not have true weight loss (1), and in up to 25% of cases with documented weight loss and thorough evaluation, no cause is ever found (3,5).
3. Is there a physical cause? One-third of cases will be caused by depression, dementia, or social factors (1,2) (Chapters 3.3 and 4.4).
B. Categories of weight loss. The evaluation of weight loss can be divided into four major categories: decreased intake, increased nutrient loss, increased metabolic demand, and impaired absorption (Table 2.7).
C. Special considerations
1. A tailored approach in the elderly includes greater emphasis on social factors.
2. The approach in human immunodeficiency virus infection and acquired immunodeficiency syndrome is more comprehensive, and special attention is given to disease-specific infections, nutritional changes, and neoplasia.
History: Initial data
A. Is the loss intentional? Consider dieting, diuretics, and eating disorders.
B. What is the patient’s average daily or weekly intake? Consider frequency of meals, appetite changes, and difficulty with food preparation.
C. Tobacco, alcohol, and drug histories are very important and frequently lead to other concerns.
D. Chronic conditions? Medical, surgical, psychiatric, and family histories are always pertinent.
E. Social factors include stress, isolation, and the cost and effort required to eat.
Basic physical examination
A. Relevant physical findings will be present in 66% of cases (1,2,5).
B. Quantify loss by serial weight measurements.
C. Check the vital signs: temperature, blood pressure, and respiratory and heart rates. Consider determining oxygen saturation.
D. Perform a physical examination, with emphasis on areas suggested by clues from the history.
Testing
A. Basic laboratory tests. Debate continues regarding the most useful and cost-effective laboratory testing for involuntary weight loss. A structured approach is best (1–5). Useful tests include:
1. Complete blood count, thyrotropin assay, urinalysis, and fecal occult blood testing.
2. Comprehensive chemistry panel including albumin, transaminases, blood urea nitrogen, creatinine, and electrolytes—calcium, magnesium, phosphorus, sodium, and potassium.
3. Chest radiograph is often useful but not required (1).
B. Comprehensive analysis. Further testing should be done only as directed by the initial findings. Careful observation and follow-up are superior management strategies to undirected diagnostic testing (1–5).
1. When indicated, upper gastrointestinal radiographs, endoscopy, and colonoscopy are the most useful second-line tests (3).
2. National Cancer Institute or United States Preventive Services Task Force age-specific screening guidelines should be considered and brought up to date for the patient. These can be accessed on the internet through the National Library of Medicine (http://www.nlm.nih.gov).
3. Computed tomography and other expensive investigations are seldom beneficial in the absence of a specific (often guideline-based) indication (3,4).
Diagnostic assessment.
The integration of history, examination, and laboratory data usually reveals the cause for involuntary weight loss.
A. Cancer, including gastrointestinal malignancies, accounts for 16% to 36% of cases, and other gastrointestinal diseases account for another 14% to 23% (1,3).
B. If the initial steps are not conclusive, the best approach is careful observation. Follow-up examinations and testing should be done monthly for 6 months. If a physical cause exists, it will almost always be found within this time (1).
C. If an organic cause is present, this simple approach will find it more than 75% of the time (1–3).
D. If an organic cause is not identified in 6 months, one is unlikely to be found (1–3). These undifferentiated patients, however, do well and have an excellent prognosis, assuming they do not have continued and progressive weight loss (1).
E. Malignancy is a significant cause of weight loss; however, a truly occult malignancy is rare and an exhaustive search for one is not supported by the literature (1–5).
References
1. Marton KI, Sox Jr HC, Krupp JR. Involuntary weight loss: diagnostic and prognostic significance. Ann Intern Med 1981;95:568–574.
2. Rabinovitz M, Pitlik SD, Leifer M, et al. Unintentional weight loss. A retrospective analysis of 154 cases. Arch Intern Med 1986;146:186–187.
3. Thompson MP, Morris LK. Unexplained weight loss in the ambulatory elderly. J Am Geriatr Soc 1991;39:497–500.
4. Wise GR, Craig D. Evaluation of involuntary weight loss. Where do you start? Postgrad Med 1994;95:143–146, 149–150.
5. Reife CM. Involuntary weight loss. Med Clin North Am 1995;79(2):299–313.
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Book Source Details
- Book Title: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter
- Author(s): Robert B. Taylor (editor)
- Year of Publication: 2000
- Copyright Details: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, Copyright © 2000 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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