Diarrhea

also see Viral gastroenteritis, Diarrhea of Infancy, Chronic nonspecific aka Toddlers Diarrhea, GI Bleeding

Etiology of Acute Diarrhea:

• Viruses: rotavirus, enteric adenovirus,norwalk-like,caliciviruses,astroviruses
• Parasites: giardia lamblia, crptosporidia, entamoeba histolytica
• Preformed bacterial toxins: staph aureus, bacillus cereus, clostridiabotulinum
• Bacteria: campylobacter, shigella, salmonella, yersinia, C.difficile, and E.coli
  • EnteropathogenicE.coli(EPEC): characterized by watery diarrhea, often chronic without fever
  • EnterotoxigenicE.coli(ETEC): self-limited acute watery diarrhea, usually without fever, most common cause oftraveller'sdiarrhea
  • Enterohemorrhagic E.coli(EHEC):afebrile, bloody diarrhea, associated with HUS
  • EnteroinvasiveE.coli (EIEC): acutedysentary
• Predominant causes of outbreaks in daycare: rotavirus,giardia,calcivirus,campylobacter, and shigella
• Non-infectious causes: dietary protein-inducedenterocolitis, Hirschsprung'sdisease,Chron'sdisease, Ulcerative colitis, radiation colitis
• bloody diarrhea in infancy may be caused by Wiscott-Aldritch

Causes of Chronic Diarrhea:

• Birth to 4 months of age: cow and soy protein-induced mucosal injury, malabsorption following infectious insult, cystic fibrosis, short bowel syndrome (resection, congenital), congenital monosaccharide transport defects, acrodermatitis enterohepatica, congenital disaccharidasedeficiency, microvillous inclusion disease
• 4 months to 3 years of age: chronic non-specific diarrhea of childhood, milk and/or protein sensitivity, giardiasis, celiacsprue,sucrase-isomaltasedeficiency
• 3 years to end of childhood:giardiasis, celiac disease, IBD, lactosemalabsorption, irritable bowel syndrome

Causes of secretory diarrhea:

• enterotoxin - producing bacteria
• cholera, neural crest tumors
• familial chloridorrhea (defect of ileal chloride transport; have watery diarrhea as the result of accumulation of chloride ion in intestinal lumen)

Causes of osmotic diarrhea:

• lactase deficiency (congenital or acquired)
• sucrase-isomaltase deficiency
• congenital glucose or fructose transport defect
• ingestion of nonabsorbablecarbohydrate (sorbitol).

Causes of fat malabsorption:

• small intestinal disorders –celiac disease, immune defects, intestinal lymphangiectasia, eosinophilic gastroenteritis, abetalipoproteinemia
• Wolman'sdisease (alysosomalstorage disease resulting in accumulation of cholesterol esters andtriglyceridesin most of the visceral organs; fatal in infancy)
• pancreatic insufficiency –cystic fibrosis,Shwachman-Diamond syndrome, chronic pancreatitis
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CHLA Board Review 2005