Chronic diarrhea is still an important cause of morbidity and mortality in children. There are several causes of chronic diarrhea which may be due to intestinal, extra-intestinal or underlying systemic diseases. The etiology varies depending on the age of onset and may include both common and uncommon disorders. In this article some of the uncommon disorders such as immune deficiencies, intestinal lymphangiectasias, drug induced diarrhea, eosinophilic gastrointestinal disorders, endocrinopathies, neuroendocrine secretory tumors, malignancy and factitious diarrhea have been included. Though these disorders are uncommon it is essential that they are considered in select situations as detailed below and evaluated so that definitive therapy may be offered.

This case of ascending paralysis, following an episode of diarrhea, was initially misinterpreted as Guillain-Barré syndrome. The prominent hypokalemia led to the search for other differential diagnoses, initially interpreted as a rare case of periodic hypokalemic paralysis, which usually occurs in Asians after intake of large amounts of starch foods, such as Spaghetti, or rest after heavy exercise. In this case, the reason for the hypokalemia with associated paralysis was caused by a hyperhyreosis factitia through denied intake of T3.

Factitious disorder is a rare psychiatric illness characterized by the willful and deceptive induction of illness for the purpose of assuming the sick role. It presents a substantial diagnostic challenge, as patients often go to great lengths to conceal their deception. Accordingly, its presence in the full spectrum of gastrointestinal diseases is likely underappreciated. While factitious gastrointestinal bleeding, abdominal pain and diarrhea are relatively common, factitious non-gastrointestinal symptoms in the setting of gastrointestinal illness have been infrequently reported. We present the case of a patient with Crohn's disease with recurrent pancytopenia attributed to the surreptitious ingestion of 6-mercaptopurine. In patients with possible access to immunomodulatory drugs, a high suspicion for and early identification of factitious disorder may improve patient outcomes and avoid invasive and costly diagnostic evaluations.

The aetiology of diarrhoea can often be simple to identify, but in some cases may pose a challenge. The diagnosis of drug-induced diarrhoea can easily be sorted based on timing of the symptom with onset of a new drug. Treatment can vary from simply monitoring and eventual resolution with continuation of the drug, to discontinuation of the offending agent. In cases where a drug cannot always be stopped, additional medications can help control the symptom. Factitious diarrhoea can present a diagnostic challenge if the evaluating physician does not suspect its possibility. Typically a careful history, and in some cases, stool testing can provide clues. The diagnosis of idiopathic diarrhoea is often made when exhaustive testing provides no definite aetiology and the goal of management is supportive care and symptomatic treatment.

Laxatives have been used for health purposes for over 2000 years, and for much of that time abuse or misuse of laxatives has occurred. Individuals who abuse laxatives can generally be categorized as falling into one of four groups. By far the largest group is made up of individuals suffering from an eating disorder such as anorexia or bulimia nervosa. The prevalence of laxative abuse has been reported to range from approximately 10% to 60% of individuals in this group. The second group consists of individuals who are generally middle aged or older who begin using laxatives when constipated but continue to overuse them. This pattern may be promulgated on certain beliefs that daily bowel movements are necessary for good health. The third group includes individuals engaged in certain types of athletic training, including sports with set weight limits. The fourth group contains surreptitious laxative abusers who use the drugs to cause factitious diarrhoea and may have a factitious disorder. Normal bowel function consists of the absorption of nutrients, electrolytes and water from the gut. Most nutrients are absorbed in the small intestine, while the large bowel absorbs primarily water. There are several types of laxatives available, including stimulant agents, saline and osmotic products, bulking agents and surfactants. The most frequently abused group of laxatives are of the stimulant class. This may be related to the quick action of stimulants, particularly in individuals with eating disorders as they may erroneously believe that they can avoid the absorption of calories via the resulting diarrhoea. Medical problems associated with laxative abuse include electrolyte and acid/base changes that can involve the renal and cardiovascular systems and may become life threatening. The renin-aldosterone system becomes activated due to the loss of fluid, which leads to oedema and acute weight gain when the laxative is discontinued. This can result in reinforcing further laxative abuse when a patient feels bloated and has gained weight. Treatment begins with a high level of suspicion, particularly when a patient presents with alternating diarrhoea and constipation as well as other gastrointestinal complaints. Checking serum electrolytes and the acid/base status can identify individuals who may need medical stabilization and confirm the severity of the abuse. The first step in treating laxative misuse once it is identified is to determine what may be promoting the behaviour, such as an eating disorder or use based on misinformation regarding what constitutes a healthy bowel habit. The first intervention would be to stop the stimulant laxatives and replace them with fibre/osmotic supplements utilized to establish normal bowel movements. Education and further treatment may be required to maintain a healthy bowel programme. In the case of an eating disorder, referral for psychiatric treatment is essential to lessen the reliance on laxatives as a method to alter weight and shape.

A 23-year-old female with a history of a histologically confirmed diagnosis of celiac disease was referred to our institution for refractory celiac disease for consideration of immunosuppressive therapy. Full workup revealed an elevated fecal magnesium level, and a concurrent diagnosis of laxative abuse was confirmed after discussion with the family. This case highlights the importance of considering factitious diarrhea in all patients admitted for refractory diarrhea, even those with documented underlying conditions.

We report two cases of factitious diarrhoea caused by stool dilution. In the first report stools from a patient with chronic diarrhoea were found to have been diluted with urine, and the diarrhoea further compounded by surreptitious laxative misuse. In the second report, after prolonged investigation of high output ileostomy, the patient's ileal effluent was found to have been diluted with water. We conclude that factitious diarrhoea, in particular dilutional diarrhoea, is over-investigated and underdiagnosed. Stool weights, complete input/output measurement, analysis of stool osmolality and electrolytes, and laxative screening are essential in the investigation of chronic watery diarrhoea.