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Case Report

Factitious Diarrhea: A Case of Watery Deception

Katz, Sherri L.; McGee, Phyllis; Geist, Rose; Durie, Peter

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Journal of Pediatric Gastroenterology and Nutrition: November 2001 - Volume 33 - Issue 5 - p 607-609
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Falsification of illness occurs when a patient fabricates symptoms or induces a physical illness. A recent review of the literature covering the past 3 decades identified 42 published case studies of falsified illness in children younger than 18 years of age (1). The psychiatric term for illness falsification is “factitious disorder,” which is defined as an intentional, self-inflicted, or fabricated illness or symptom motivated solely by the individual's need to assume the sick role, without external incentives (2). Children are at risk of developing a chronic pattern of illness falsification with the potential for serious self-harm as the sophistication of their fabrications increase. Therefore, early detection and intervention is essential (1).

We report a unique case of a factitious illness in which an adolescent diluted stool samples with water to feign chronic diarrhea. The purpose of this report is to heighten awareness of the existence of factitious illnesses in childhood and adolescence and to discuss the diagnosis of factitious diarrhea.


A 16-year-old boy had a 5-month history of frequent watery stools (15–20 times/d) that began following antibiotic therapy for sinusitis. The stools were never solid, contained no blood or mucous, and had the appearance of urine containing particulate matter. There was no nocturnal diarrhea and no association of diarrhea with specific nutrients. A lactose-free diet produced no change in symptoms. He had no history of travel.

The patient also complained of intermittent periumbilical abdominal pain, fatigue, decreased appetite, and weight loss of 10 to 15 pounds. A 5-pound weight loss was documents during the 5 months before admission. The patient had no fever, change in urine output, or dysuria. No fecal matter was noted in the urine. He found the diarrhea to be embarrassing and at times wore protective clothing because he claimed that he was incontinent. He reported feeling “sad” because the diarrhea prevented him from remaining in residence at his school. He had developed abdominal pain and depression when his parents had separated 3 years earlier. The symptoms resolved when the family was reunited. The patient had severe learning disabilities and had been attending a residential school for children with special needs for 2 years. He denied suicidal ideation. The patient took no medications, had no known allergies, and denied abuse of laxatives or other substances.

The patient underwent extensive investigation as an outpatient. Complete blood count, erythrocyte sedimentation rate, alpha 1 -acid glycoprotein, serum protein, albumin, vitamin B12, ferritin, carotene, immunoglobulins, and liver function tests were all normal. A fecal alpha 1 -antitrypsin clearance study was normal. A lactose breath hydrogen test, antiendomysial antibody, and 72-hour fecal fat balance study were within normal limits. Investigations for secretory causes of diarrhea including serum cortisol, urinary vanillylmandelic acid, homovanillic acid, norepinephrine, and dopamine were normal. Stool samples were negative for bacteria, Clostridium difficile toxin, and viral and parasitic pathogens.

Results of an abdominal ultrasound and barium enema were normal. Esophagogastroduodenoscopy and sigmoidoscopy revealed normal appearance and histology. Pasty stool was identified in the upper rectum. Serum electrolytes, urea, creatinine, and urinalysis were within normal limits. A 24-hour stool collection, performed at home, produced 16 L. The electrolyte composition of several separate containers revealed a mean sodium of 2 mmol/L, potassium of 0.2 mmol/L, and osmolality of 9 mOsm/kg water (Table 1). The high stool volume and suspiciously low electrolyte concentration suggested stool dilution. When confronted, the patient denied fabricating his symptoms, and his parents also rejected this possibility. This prompted a hospital admission.

Stool electrolyte composition and osmolality

At the time of admission, physical examination was normal. Formed stool was palpable on rectal examination. Fluid balance and stooling patterns were documented, and all stools were collected for volume, electrolyte composition, and osmolality (Table 1). The parents agreed to remain away from the hospital for a 72-hour period. During the first 24 hours, the patient had frequent watery stools and the fluid balance recorded a deficit of 2.5 L. However, the patient's weight was unchanged, his vital signs were stable, and he exhibited no signs of dehydration.

On the second day, because of theoretical concerns about excessive fluid loss and the risk of cardiovascular collapse, constant observation during defecation and urination was implemented with the patient's consent. Within 2 hours, he produced a formed stool, and stated that he was `feeling much better.` During the ensuing 2 days in the hospital, he produced only formed stools, which could not be analyzed for electrolyte composition or osmolality because of their high viscosity.

The patient again denied that he was diluting his stools but was grateful for being cured. A psychiatric assessment revealed that he did not meet the criteria for depression. He expressed anxiety about being unable to meet high parental expectations, especially at school, and was stressed by separation from his family while at school and in the hospital. He possessed limited abstract verbal skills making it difficult for him to communicate his anxieties to his parents.


This case illustrates a scenario in which the patient's symptom of diarrhea was the manifestation of a factitious disorder. The diagnosis was suspected when physical signs were inconsistent with the history and presenting complaint. These included a lack of clinical findings of severe disease or dehydration, despite huge daily stool losses. Laxative abuse, ingestion of osmotic agents (i.e., apple juice or sorbitol), and bacteria containing substances (i.e., feces) (3) may induce factitious diarrhea. Alternatively, symptoms of diarrhea may be fabricated by diluting the stool with water or urine (4). Ewe and Karbach (5) suggest that factitious diarrhea should be suspected in adults when stool output is greater than 500 g per day.

Determination of stool electrolytes and osmolality will confirm the diagnosis of factitious diarrhea because low values can be explained only by the addition of water to the specimen. The colon cannot excrete free water, because it crosses the intestinal epithelium as a result of active transport of solutes (6,7).

Phillips et al. (4), retrospectively reviewed the results of all stool specimens referred for analysis to a tertiary care laboratory over a 6-year period. Of 325 stool samples obtained from patients with diarrhea for at least 4 weeks, 202 were considered to be appropriate for analysis. More than 90% of these subjects were outpatients. Stool samples were measured for pH, osmolality, and electrolyte composition. In addition, the osmotic gap was calculated. Evidence of factitious diarrhea because of laxative use or stool dilution was found in 35 of 202 (17%) patients. Five of these patients had hypotonic stools and were assumed to have mixed their stools with water or another hypotonic fluid. The authors of this study concluded that fecal water analysis is essential for determining the pathogenesis of diarrhea. These tests are considerably less expensive than alternative invasive tests and can be performed in any hospital laboratory.

Two cases of factitious diarrhea by stool dilution have been reported in adults (7). Stool osmolality was significantly less than the osmolality of serum, and the diagnosis of factitious diarrhea was confirmed by the presence of normal stool osmolality when defecation was supervised or when colonic contents were sampled endoscopically.

This patient's stool electrolytes and stool osmolality confirmed that the diarrhea was factitious, not from laxative abuse, but from dilution of the stool with water. This case has similarities to other cases of factitious diarrhea but is unique in several aspects. First, there are only a few reported cases of factitious diarrhea by stool dilution (7). The most common cause of factitious diarrhea in adults is laxative ingestion (3,4). Second, there was no known active parental involvement. In children and adolescents, factitious diarrhea is a common presentation of Munchausen by proxy in which the caregiver, generally the mother, is responsible for inducing diarrhea in the child (8,9).

Phenolphthalein administration, ipecac poisoning, and diet manipulation have been reported as methods of parental-induced diarrhea (10–13). Finally, although factitious diarrhea is a well-recognized manifestation of factitious illness in adults (3,4), no case reports of factitious diarrhea in adolescents were found in the literature (1).

The pathogenic factors involved in the development of factitious disorders remain unclear. As with this case, illness falsification often begins with a legitimate but self-limited illness (14). Munchausen syndrome, the best-studied subtype of factitious disorders, has been hypothesized to originate from a precipitating event, often separation from a person toward whom the patient experiences intensely ambivalent emotions (15). All such patients demonstrate a desperate plea for help by a person who has been unable to devise a better solution to his or her emotional problems (16).

Factitious disorders require diagnosis and treatment. If we had failed to diligently search for a cause, resolution of symptoms would not have occurred and an opportunity to examine the deeper underlying issues in this case would have been missed. Although clinical course is variable and often chronic, its prognosis may be more optimistic for adolescents than for adults and early intervention may prevent chronic patterns of illness falsification later in life (1). Unfortunately, at least one family member usually fails to comply with the recommendation for ongoing outpatient psychiatric counseling. This family was lost to follow-up.

To conclude, this is the first reported case of factitious diarrhea produced by adding water to the stool in an adolescent. In this case, simple analysis of stools for electrolytes and osmolality provided proof that the diarrhea was indeed factitious. Symptom or illness falsification should be considered in any child when the history and physical findings are inconsistent with the presenting symptoms.


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    © 2001 Lippincott Williams & Wilkins, Inc.