Snapshot A 12-year-old boy is brought to the clinic for diarrhea and vomiting. He has no fever but complains of intermittent, cramp, abdominal pain. They just returned from a family picnic, where, about two hours ago the child ate potato salad. The mother reports other family members had become ill after the meal as well. (Staphylococcus aureus) Introduction Diarrhea defined as stool with increased water content, volume, or frequency (> 250 grams/day) Time course: acute diarrhea lasts < 14 days persistent diarrhea lasts 2 - 4 weeks chronic diarrhea lasts > 4 weeks Types of diarrhea: invasive/inflammatory non-invasive, non-inflammatory osmotic diarrhea secretory diarrhea Presentation Symptoms abdominal pain and cramping watery diarrhea bloody diarrhea general malaise Physical exam +/- fever signs of dehydration dry mucous membranes lethargy dry skin headache Evaluation Acute diarrhea does not routinely require laboratory evaluation, unless there is: high fever (≥ 38.5ºC (101.3ºF)) bloody diarrhea lasts longer than four days severe abdominal pain hospitalized patients elderly (> 70) immunocompromised other systemic illness General evaluation includes methylene blue stool study if positive then leukocytes are present, indicating inflammatory diarrhea CBC, ESR, BMP stool smear for fecal leukocytes C. difficile toxin stool culture ova and parasites consider sigmoidoscopy in patients with severe proctitis, bloody diarrhea, or possible C. dificil Differential Depends on both the time course and type of diarrhea Infectious causes include: viruses (rotavirus, norovirus, CMV, hep A) bacteria (Campylobacter, C. difficile, Salmonella, Shigella and E. coli) parasites (Giardia, Entamoeba histolytica, Cryptosporidium) for full list of bugs causing diarrhea, see Microbiology topic Noninfectious causes include: medication adverse effects antibiotics antibiotics can destroy normal flora and allow infection with Clostridium dificile treatment: first line: metronidazole second line: vancomycin third line: fidaxomicin laxatives chemotherapeutics acute abdominal processes diverticulitis gastroenterologic disease IBD IBS celiac disease small intestine bacterial overgrowth secondary to stasis (can occur in scleroderma) allergy or intolerance lactose intolerance artificial sweetener allergy endocrine disease carcinoid syndrome factitious laxative abuse iatrogenic radiation therapy post-surgery (i.e. gastric bypass) Treatment Conservative oral rehydration salts IV fluids, if severe dehydration or patient unable to take PO liquids electrolyte replacement (Na+, K+) Pharmacologic (acute) antidiarrheal agents such as loperamide and bismuth salicylate most infectious causes are self-limited if severe diarrhea, consider IV antibiotics definitive treatment depends on the cause of diarrhea (see the above differential)