Diarrhea can be defined as the passage of:[1]World Health Organization. Health topics - diarrhoea. 2017 [internet publication].
http://www.who.int/topics/diarrhoea/en
[2]Riddle MS, DuPont HL, Connor BA. ACG clinical guideline: diagnosis, treatment, and prevention of acute diarrheal infections in adults. Am J Gastroenterol. 2016 May;111(5):602-22.
http://www.spg.pt/wp-content/uploads/2015/07/2016-acute-diarrhea.pdf
http://www.ncbi.nlm.nih.gov/pubmed/27068718?tool=bestpractice.com
Three or more loose or liquid stools per 24 hours, and/or
Stools that are more frequent than what is normal for the individual lasting <14 days, and/or
Stool weight greater than 200 g/day.
Based on duration, diarrhea is classified as:[2]Riddle MS, DuPont HL, Connor BA. ACG clinical guideline: diagnosis, treatment, and prevention of acute diarrheal infections in adults. Am J Gastroenterol. 2016 May;111(5):602-22.
http://www.spg.pt/wp-content/uploads/2015/07/2016-acute-diarrhea.pdf
http://www.ncbi.nlm.nih.gov/pubmed/27068718?tool=bestpractice.com
[3]Arasaradnam RP, Brown S, Forbes A, et al. Guidelines for the investigation of chronic diarrhoea in adults: British Society of Gastroenterology, 3rd edition. Gut. 2018 Aug;67(8):1380-99.
https://gut.bmj.com/content/67/8/1380.long
http://www.ncbi.nlm.nih.gov/pubmed/29653941?tool=bestpractice.com
[4]World Gastroenterology Organisation. Acute diarrhea in adults and children: a global perspective. 2012 [internet publication].
http://www.worldgastroenterology.org/guidelines/global-guidelines/acute-diarrhea/acute-diarrhea-english
[5]Shane AL, Mody RK, Crump JA, et al. 2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea. Clin Infect Dis. 2017 Nov 29;65(12):e45-80.
https://academic.oup.com/cid/article/65/12/e45/4557073
http://www.ncbi.nlm.nih.gov/pubmed/29053792?tool=bestpractice.com
Epidemiology
In 2016, diarrhea was the eighth leading cause of death among all ages and the fifth leading cause of death among children younger than 5 years.[6]GBD 2016 Diarrhoeal Disease Collaborators. Estimates of the global, regional, and national morbidity, mortality, and aetiologies of diarrhoea in 195 countries: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Infect Dis. 2018 Nov;18(11):1211-28.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6202444
http://www.ncbi.nlm.nih.gov/pubmed/30243583?tool=bestpractice.com
Worldwide, it has been estimated that there are 2 billion episodes of diarrheal illness per year.[4]World Gastroenterology Organisation. Acute diarrhea in adults and children: a global perspective. 2012 [internet publication].
http://www.worldgastroenterology.org/guidelines/global-guidelines/acute-diarrhea/acute-diarrhea-english
Death due to diarrhea disproportionately affects postneonatal children <5 years.[4]World Gastroenterology Organisation. Acute diarrhea in adults and children: a global perspective. 2012 [internet publication].
http://www.worldgastroenterology.org/guidelines/global-guidelines/acute-diarrhea/acute-diarrhea-english
However, with implementation of improved access to oral rehydration therapy (ORT), vitamin supplementation, rotavirus vaccines, and education on feeding and weaning, it is estimated that mortality has dropped from 3.9 million deaths in 1967 to 526,000 in 2015.[7]Black R, Fontaine O, Lamberti L, et al. Drivers of the reduction in childhood diarrhea mortality 1980-2015 and interventions to eliminate preventable diarrhea deaths by 2030. J Glob Health. 2019 Dec;9(2):020801.
https://jogh.org/documents/issue201902/jogh-09-020801.pdf
http://www.ncbi.nlm.nih.gov/pubmed/31673345?tool=bestpractice.com
Additionally, new antisecretory agents have shown promise in conjunction with ORT to reduce diarrhea volume burden.[8]Eberlin M, Chen M, Mueck T, et al. Racecadotril in the treatment of acute diarrhea in children: a systematic, comprehensive review and meta-analysis of randomized controlled trials. BMC Pediatr. 2018 Apr 3;18(1):124.
https://bmcpediatr.biomedcentral.com/articles/10.1186/s12887-018-1095-x
http://www.ncbi.nlm.nih.gov/pubmed/29614995?tool=bestpractice.com
Despite the improvement, diarrhea remains the third leading cause of death in postneonatal children <5 years, after pneumonia and preterm birth/neonatal disorders.[9]Centers for Disease Control and Prevention. Global diarrhea burden. Dec 2015 [internet publication].
https://www.cdc.gov/healthywater/global/diarrhea-burden.html
[10]World Health Organization. Children: reducing mortality. Oct 2017 [internet publication].
http://www.who.int/mediacentre/factsheets/fs178/en
Around 47.8 million cases of acute diarrheal infection occur each year in the US, with an estimated cost of at least US$150 million to the healthcare economy.[11]Scallan E, Griffin PM, Angulo FJ, et al. Foodborne illness acquired in the United States: unspecified agents. Emerg Infect Dis. 2011 Jan;17(1):16-22.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3204615
http://www.ncbi.nlm.nih.gov/pubmed/21192849?tool=bestpractice.com
[12]Scallan E, Hoekstra RM, Angulo FJ, et al. Foodborne illness acquired in the United States: major pathogens. Emerg Infect Dis. 2011 Jan;17(1):7-15.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3375761
http://www.ncbi.nlm.nih.gov/pubmed/21192848?tool=bestpractice.com
Basic pathophysiology
Normally, approximately 10 liters of fluid consisting of ingested food and drink, in addition to secretions from the salivary glands, stomach, pancreas, bile ducts, and duodenum, enters the gastrointestinal tract every day. The small intestine is the major site for reabsorption. Overall, about 99% of the fluid is reabsorbed, leaving 0.1 liter to be excreted in the feces. Diarrhea occurs when various factors interfere with this normal process, resulting in decreased absorption or increased secretion of fluid and electrolytes, or increase in bowel motility.
Improved understanding of the pathophysiology of infectious diarrhea, and the factors that promote the spread of causative infectious agents, will lead to practical approaches for preventing and responding to outbreaks.[13]Pawlowski SW, Warren CA, Guerrant R. Diagnosis and treatment of acute or persistent diarrhea. Gastroenterology. 2009 May;136(6):1874-86.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2723735
http://www.ncbi.nlm.nih.gov/pubmed/19457416?tool=bestpractice.com
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