Evaluation acute diarrhea

(NEJM 2014;370:1532; Digestion 2017;95:293; PLOS One 2017;12:11) Acute infectious diarrhea in immunocompetent adults.

• Ddx: hyperthyroid, adrenal insufficiency, meds (abx, antacids, immune checkpt inhibitors), appendicitis, diverticulitis, radiation, 1st presentation of bowel disorder (eg, IBD, celiac)

• History: stool freq, blood, abd pain, duration of sxs [~1 wk for viral & bacterial (except C. diff), >1 wk for parasitic], travel, food, recent abx, immunocompromise

• PEx: vol depletion (VS, UOP, axillae, skin turgor, MS), fever, abd tenderness, ileus, rash

• Laboratory: calprotectin, stool cx, BCx, lytes, C. diff (if recent hosp/abx), stool O&P (if >10 d, travel to endemic area, exposure to unpurified H2O, community outbreak, daycare, HIV ⊕ or MSM); ± stool ELISAs (viruses, Crypto, Giardia), serologies (E. histolytica); PCR available (but high ⊕ rate & unclear if true vs. colonized; consider if immunocompromised)

• Imaging/endoscopy: consider if warning signs (WS) of fever, severe abd pain, blood or pus in stool, >6 stools/d, severe dehydration, immunosupp, elderly, duration >7 d, hosp-acquired. CT/KUB if ? toxic megacolon; sig/colo if immunosupp or cx ⊖.