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Chapter 040. Diarrhea and Constipation (Part 11)

FACTITIAL CAUSES Factitial diarrhea accounts for up to 15% of unexplained diarrheas referred to tertiary care centers. Either as a form of Munchausen syndrome (deception or self-injury for secondary gain) or eating disorders, some patients covertly selfadminister laxatives alone or in combination with other medications (e.g., diuretics) or surreptitiously add water or urine to stool sent for analysis. Such patients are typically women, often with histories of psychiatric illness and disproportionately from careers in health care. Hypotension and hypokalemia are common co-presenting features. The evaluation of such patients may be difficult: contamination of the stool with water or urine. | Chapter 040. Diarrhea and Constipation Part 11 FACTITIAL CAUSES Factitial diarrhea accounts for up to 15 of unexplained diarrheas referred to tertiary care centers. Either as a form of Munchausen syndrome deception or self-injury for secondary gain or eating disorders some patients covertly selfadminister laxatives alone or in combination with other medications e.g. diuretics or surreptitiously add water or urine to stool sent for analysis. Such patients are typically women often with histories of psychiatric illness and disproportionately from careers in health care. Hypotension and hypokalemia are common co-presenting features. The evaluation of such patients may be difficult contamination of the stool with water or urine is suggested by very low or high stool osmolarity respectively. Such patients often deny this possibility when confronted but they do benefit from psychiatric counseling when they acknowledge their behavior. APPROACH TO THE PATIENT CHRONIC DIARRHEA The laboratory tools available to evaluate the very common problem of chronic diarrhea are extensive and many are costly and invasive. As such the diagnostic evaluation must be rationally directed by a careful history and physical examination Fig. 40-3A . When this strategy is unrevealing simple triage tests are often warranted to direct the choice of more complex investigations Fig. 403B . The history physical examination Table 40-4 and routine blood studies should attempt to characterize the mechanism of diarrhea identify diagnostically helpful associations and assess the patient s fluid electrolyte and nutritional status. Patients should be questioned about the onset duration pattern aggravating especially diet and relieving factors and stool characteristics of their diarrhea. The presence or absence of fecal incontinence fever weight loss pain certain exposures travel medications contacts with diarrhea and common extraintestinal manifestations skin changes arthralgias oral aphthous ulcers should .