Mrs. M is an 85-year-old woman who comes to the office complaining of weight loss. She is quite concerned that she has something dreadful.
|What is the differential diagnosis of involuntary weight loss? How would you frame the differential?|
Significant involuntary weight loss (IWL) is defined as > 5% loss of usual body weight in the last 6–12 months. Significant IWL can be a harbinger of serious underlying disease. One study documented significantly increase mortality in men with IWL compared with men whose weight was stable or increased (36% vs ≈15%). There are a large number of diseases that can cause IWL, which are best organized by system (see below). The 4 most common causes of IWL are cancer (GI, lung, and lymphoma), ≈25%; nonmalignant GI diseases, 17%; depression and alcoholism, 14%; and unknown, 22%. Endocrine disorders account for 7% of IWL. Although cancer is the most common cause, it is not the cause in most patients.
Three pivotal points are worth remembering when evaluating the patient with IWL. First, the weight loss should be documented, because 25–50% of patients who complain of IWL, have not in fact lost weight. Elderly adults often lose muscle mass and simply look like they lost weight. Weight loss should be documented by comparing prior weights or if these are unavailable by finding a significant decrease in a patient's clothing size.
|Clinicians should verify the weight loss or document significant changes in the patient's clothing or belt size.|
Second, inquire about symptoms of diarrhea or malabsorption. Symptoms of diarrhea, or large difficult to flush, malodorous stools suggests small bowel or pancreatic disease and directs the diagnostic search.
Third, obtain a truly comprehensive history (including a psychosocial history) and perform a detailed head to toe physical exam and a baseline laboratory evaluation to search for any subtle diagnostic clues that may help focus the evaluation (Figure 27–1).
Diagnostic approach: involuntary weight loss.
Differential Diagnosis Ofinvoluntary Weight Loss
Heart failure (severe)
Subacute bacterial endocarditis (SBE)
GI (organized from mouth to rectum)
Poor dentition (50% of patients edentulous by age 65)
Esophageal stricture or web
Peptic ulcer disease (PUD)
Gastric outlet obstruction
Small bowel diseases
Bacterial overgrowth syndromes
Chronic GI infections
Infectious: HIV infection or complications
Poverty (15% of patients over age 65 live below the poverty line)
Immobility or inadequate transportation
Chronic obstructive pulmonary disease (severe)
Systemic lupus erythematosus
Drugs (eg, digoxin, loop diuretics, diltiazem, levodopa)
Mrs. M reports that she has lost weight over the last 6 months. She denies any diarrhea, loose, or difficult to flush stools. She reports that her appetite is poor and she feels fatigued.
|At this point, what is the leading hypothesis, what are the active alternatives, and is there a must not miss diagnosis? Given this differential diagnosis, what tests should be ordered?|
The patient's history is typical of many patients complaining of weight loss. Patients report an unspecified amount of weight loss, associated with anorexia. The first pivotal step in the evaluation is to verify that weight loss did in fact occur.
Mrs. M does not remember her prior weight but reports that her clothes are much too loose. Indeed, she has gone out to buy clothes 2 sizes smaller.
Mrs. M's change in clothing size suggests true and significant weight loss. The second pivotal step in evaluating patients with documented weight loss determines whether the patient has symptoms suggestive of diarrhea or malabsorption. Since the history does not suggest diarrhea or malabsorption, the third pivotal step in the evaluation of these patients is a comprehensive, system-based approach utilizing a thorough history and physical exam as well as basic laboratory exams (CBC, urinalysis, renal panel, calcium, liver panel, fecal occult blood test (FOBT), erythrocyte sedimentation rate (ESR), TSH, and chest radiograph). The myriad of diseases associated with IWL make it vital to search for clues before beginning a more expensive and indiscriminate investigation. In the absence of specific clues, focus first on cancer (the most common cause of IWL and the leading hypothesis) and then on other common causes, including nonmalignant GI disease, psychosocial disease, and hyperthyroidism (active alternatives). SBE, HIV, temporal arteritis, and tuberculosis are “must not miss” alternatives.
Finally, malabsorption should be reconsidered if the evaluation is negative, since patients with malabsorption may not have diarrhea or foul stools. Table 27–1 lists the differential diagnosis.
Table 27–1. Diagnostic Hypotheses for Mrs. M.
| Save Table
Table 27–1. Diagnostic Hypotheses for Mrs. M.
|Diagnostic Hypotheses||Clinical Clues||Important Tests|
|Stomach||Early satiety||EGD or upper GI|
Change in stools
Positive FOBT, iron deficient anemia
|Chest radiograph, chest CT scan|
Jaundice, dark urine (bilirubinuria)
|Abdominal ultrasound or CT scan|
|Active Alternatives—Most Common|
|Nonmalignant GI disease|
|Dental||New ill-fitting dentures|
|Esophageal disease||Dysphagia||EGD or upper GI|
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