Functional Diarrhea
Section snippets
Introduction and definition
Chronic diarrhea is a frequent presenting symptom, seen by both general practitioners and gastroenterologists. The differential diagnosis is broad, and diagnostic evaluation may be complex.1, 2, 3
In spite of the large number of causes of chronic diarrhea, and in spite of extensive investigations, no cause for the symptoms is found in a large group of patients, who are referred to as having functional diarrhea.3
According to the Rome III Diagnostic Criteria for Functional Gastrointestinal
Epidemiology
The prevalence of functional diarrhea in the population is poorly studied. Most available surveys on the epidemiology of chronic diarrhea have not systematically distinguished D-IBS from other types of chronic diarrhea, and in a condition with such a broad differential diagnosis, symptom-based criteria are insufficient to exclude several organic causes. Nevertheless, a telephone survey in the United States found that 26.9% of 1017 respondents reported symptoms of diarrhea or loose stools in the
Diagnostic approach
History taking should evaluate the ingestion of poorly absorbed carbohydrates (fructose, sorbitol, and so forth), which may cause diarrhea, or a link between symptoms and ingestion of dairy products, suggestive of lactose intolerance. The Bristol stool form scale can be used as a visual aid to confirm a patient's usual stool consistency. Medication use needs to be assessed, because several drugs (magnesium-containing antacids; lipase inhibitors, such as orlistat; prokinetics, such as
Pathophysiologic mechanisms in functional diarrhea
Although many studies have addressed pathophysiologic mechanisms in D-IBS, functional diarrhea is poorly studied. The stool consistency, which is a key feature in the Rome III definition of functional diarrhea, suggests that rapid bowel transit is present in patients with chronic diarrhea.3, 5 In keeping with an underlying motility disorder, a colonic manometry study found increased propagating colonic contractions and decreased nonpropagating contractions in functional diarrhea patients.10
Treatment approach
Clear explanation of the symptoms and diagnosis and reassurance about the benign nature of chronic functional diarrhoea are important. It is worthwhile to discuss potential triggering factors, such as specific foods, stress, and anxiety. Dietary restrictions of food components, such as fructose, sorbitol, caffeine, or other precipitating foods, are generally proposed as a first approach.2, 3, 9 A trial of lactose elimination can be advocated in those who consume milk products on a regular basis.
Opioid Agonists
Opioid receptor ligands are the most frequently used agents in the (symptomatic) treatment of diarrhea. Morphine is well known to slow gastrointestinal transit and codeine, a μ-opioid receptor agonist, is less potent but also has antidiarrheal properties. Because of their central effects and risk of habituation, these opioids are usually avoided in the treatment of chronic diarrhea. Diphenoxylate and loperamide, especially, are preferentially used because they lack central nervous system
Bile-Acid Binding Agents
Up to 50% of patients with chronic idiopathic diarrhea have bile acid malabsorption.36, 37, 38, 39, 40, 41, 42, 43 Studies report that this is the group of patients that responds best to cholestyramine treatment. Cholestyramine and related binding resins improve urgency and stool consistency and reduce stool frequency and stool weight.39, 44, 45 The dose used is 4 g, up to 3 times daily, with the early morning dose considered the most important. Palatability and solubility of cholestyramine are
Proabsorptive drugs: clonidine
In diabetic diarrhea, efficacy of clonidine, a proabsorptive agent, in doses up to 300 μg, 3 times a day, has been reported.53 The beneficial effects of clonidine probably also include motility components, because the drug was shown to slow intestinal transit and to inhibit colonic tone in health.54, 55 The efficacy of clonidine in nondiabetic chronic diarrhea has not been addressed. Taking into account the unfavorable side-effect profile, mainly due to hypotension and nausea, clonidine should
Antisecretory drugs: octreotide
The use of the somatostatin analog octreotide has been investigated in several types of chronic diarrhea, including carcinoid diarrhea, dumping syndrome, short bowel syndrome, chemotherapy-induced diarrhea, and AIDS-associated diarrhea.56 Octreotide enhances intestinal absorption and inhibits gastric, pancreatic, and intestinal secretion. Favorable responses have been reported for diabetic diarrhea as well.57
Based on these properties, octreotide has been applied in the treatment of chronic
Summary
Chronic diarrhea, specifically functional diarrhea, is a clinical problem of considerable magnitude. The epidemiology of this condition needs further studies, because the overlap with D-IBS is usually not taken into account in currently available literature. The underlying pathophysiology may involve rapid intestinal transit, but only few quality mechanistic studies are available. The role of stress, and of specific nutrient intolerances, is incompletely elucidated. In clinical practice, a
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Cited by (23)
Methods of Determining Irritable Bowel Syndrome and Efficiency of Probiotics in Treatment: A Review
2023, Current Therapeutic Research - Clinical and ExperimentalApproach to the adult patient with chronic diarrhea: a literature review
2021, Revista de Gastroenterologia de MexicoSimilarities in Clinical and Psychosocial Characteristics of Functional Diarrhea and Irritable Bowel Syndrome With Diarrhea
2020, Clinical Gastroenterology and HepatologyShen-ling-bai-zhu-san, a spleen-tonifying Chinese herbal formula, alleviates lactose-induced chronic diarrhea in rats
2019, Journal of EthnopharmacologyCitation Excerpt :Chronic diarrhea has been defined as diarrhea lasting in excess of 4 weeks, which is one of predominant symptoms in functional bowel disorders such as functional diarrhea and diarrhea-predominant irritable bowel syndrome (Lacy et al., 2016). So far, it has been thought that chronic diarrhea is closely related with rapid intestinal transit, emotions and specific nutrient intolerances (Tack, 2012). For example, lactose intolerance related chronic diarrhea is a common problem frequently encountered in the gastrointestinal clinics in China (Zheng et al., 2015; Xiong et al., 2017).
Functional diarrhea
2019, Clinical and Basic Neurogastroenterology and MotilityBowel disorders
2016, Gastroenterology
Competing interests: None declared.