| Question | Answer |
| HUS may be due to: | E coli; shigella |
| Invasive pathogens (most common causes of infxs diarrhea) | Salmonella, shigella, campy, hemorrhagic E coli |
| Other viral agents of gastroenteritis in children/adults | Norwalk virus; Astrovirus; Reovirus |
| Shigella Tx | Abx recommended (FQ or Bactrim) |
| Salmonella complications | Septicemia/Bacteremia; poss osteomyelitis, endocarditis, arthritis |
| Diarrhea | >3/day or 200 mL; osmotic vs secretory; dx: fecal WBC, occult blood, flex sig/bx, upper GI |
| Diarrhea: inflam vs non-inflammatory agents | inflam: cMV, E histo, EHEC, C diff, SSC; non-inflam: noro, rota, giardia, crypto, SA, B cereus, vibrio cholera |
| E coli: hemorrhagic colitis: | severe abd pain, bloody diarrhea (no fever usually) caused by shiga or shiga-like toxin |
| Gastroenteritis: Antimicrobial tx: used for: | shigellosis, traveler’s diarrhea, C.difficile, campylobacter; can prolong salmo/C diff shedding, or worsen shiga toxin course |
| Salmonella: gastroenteritis S/S | most common salmonella type; 8-48 hr incubation; F, N/V, crampy abd pain, bloody diarrhea 3-5d; +stool cx |
| Dx giardiasis with: | giardia antigen stool assay |
| AIDS-associated diarrhea 2/2: | Mycobacterium avium-intracellulare (MAI) |
| Tx of choice for more severe infxs diarrhea: | FQ; TMP-SMX = 2nd-line tx; Add azithro for Campy |
| Salmonella typhi Sx | 10-14d post-ingestion: fever, HA, myalgia, malaise, anorexia; followed by GI sx (GB colonization & intestine reinfxn); typhoid fever: pulse-temperature discordance; 1-5% chronic carriers |
| Loperamide | opiate w/o systemic fx; inhibits peristalsis; can use w/Abx for traveler’s diarrhea |
| DO NOT use anti-motility agents in: | pts w/shigella, C diff, E coli O157 (inflammatory diarrhea) |
| ETEC: tx | travelers diarrhea; Abx after sx onset may decrease duration; Cipro or rifaximin |
| Parasitic GI causes of diarrheal disease | G. lamblia, C. parvum, B. hominis |
| E coli group = more common in pediatric populations (usu developing countries) | Enteropath & enteroaggregative |
| Traveler’s Diarrhea is caused by: | E. coli (ETEC); tx is hydration & Cipro |
| E. coli groups = small bowel processes | Enterotoxigenic; enteropathogenic; enteroaggregative |
| Antimicrobial tx: used for: | shigellosis, traveler’s diarrhea, C.difficile, campylobacter; can prolong salmo/C diff shedding, or worsen shiga toxin course |
| Acute bacterial diarrhea w/ prodrome of HA, F, then crampy abd pain & diarrhea | Campylobacter jejuni (most common cause of acute bacterial diarrhea) |
| Shigella Sx | Lower abd cramps, diarrhea, fever, bloody, purulent stools & tenesmus; usu self-ltg (7 days) |
| V cholera S/S | rice-water stools; poss hypotensive shock within 2 hrs; dose fx; tx rehydrate & 1 dose Cipro; untx’d 50% mortality |
| Most common cause of nosocomial diarrhea | C diff (Abx-induced diarrhea); tx w/Flagyl or oral vanco |
| Vibrio | watery dia, abd cramping; V para: also wound infxn; heat to >75C to destroy; susceptible: liver dz & Fe overload states |
| Acute/ persistent/ chronic | Acute <14 days; Chronic >1 month |
| Common antibiotic causes of colitis: | Ampicillin, clindamycin, tetracycline, cephalosporins |
| Parasitic GI Syndromes in AIDS patients/protracted diarrhea: | MAI, Giardia lamblia, Cryptosporidium parvum, Isospora belli |
| Most important viral agent of gastroenteritis in children/adults | Calicivirus |
| C perfringens sx | Abd cramps & watery diarrhea without fever or N/V; lasts <24 hr |
| Most important agent of gastroenteritis in infants | Rotavirus A |
| Assessing severity of illness | dehydration; duration of sx; inflammation (fever, blood, tenesmus) |
| Diarrhea: Abx for: | Shigella, cholera, ETEC, C diff; No Abx for salmo, campy, EHEC, Yersinia |
| HUS may be due to: | E coli; shigella ETEC: tx travelers diarrhea |
| Giardia: most susceptible | immunocompromised; immunocompetent w/Ig def |
| Salmonella: bacteremia S/S | usually in immunocompromised pt; recurrent fever, local infxn (bone, joints, lungs) |
| E. coli groups = colon processes (bloody diarrhea): | enterohemorrhagic; enteroinvasive |
| Afebrile, watery or loose stool. No blood or mucus | Viral Gastroenteritis |
| Abdominal pain, diarrhea after picnic/party. Eaten ham, cream, custards, mayonnaise | Staphylococcus aureus infectious diarrhea |
| Campy Sx: | dysentery; poss bacteremia; usu self ltg (may last 1 wk/longer); assoc w/GBS & Reiters |
| Order stool studies if: | Diarrhea is persistent or recurring; h/o fever or tenesmus |
| Toxin A = enterotoxin; Toxin B = cytotoxin | C. diff |
| Shigella Sx | Lower abd cramps, diarrhea, fever, bloody, purulent stools & tenesmus; usu self-ltg (7 days) |
| Greasy, foul smelling, floating stools. Pear-shaped flagellated protozoan w/ 2 “eyes”. Water, travel, camping history | Giardia |
| Chronic diarrhea: etiology | Malabsorption; motility disorders; inflammation |
| C diff mgmt: | IV/PO Flagyl or PO vanco. 20% relapse in 1-2 wks after DC of therapy; relapses respond well to 2nd course of tx. Multiple relapses: consider taper & pulsed therapy |
| Salmonella: Enteric (typhoid) fever S/S | 5-14d incubation, insidious (kids abrupt); F, HA, ST, myalgia, malaise; abd pain, pea soup diarrhea; pulse-temperature discordance; freq relapse; 1-5% chronic carriers |
| Vibrio cholera MOA | stimulates adenyl cyclase in intestinal epithelial cells to overproduce cAMP => H2O & Cl- hypersecretion => diarrhea |
| Salmonella Sx | fevers, myalgias, abd cramping, HA; |
| Yersinia Sx: | Diarrhea, fever, abdominal pain for 1-2 wks (chronic: poss for mos); fx terminal ileum; lg lymph nodes (mimics appy); systemic dz: high mortality |
| Intestinal amoebiasis | Entamoeba histolytica |
| Oral Rehydration Solution: | 3.5 g NaCl, 2.5 g Na HCO3, 1.5 g KCl, 20 g glucose, in 1L water |
| Other agents of gastroenteritis in infants | Adenovirus (serotypes 40/41); Coxsackie Virus |
| Rice-water stools; poss hypotensive shock within 2 hrs; dose effects = | Vibrio cholera |
| Severe cases of ETEC can be treated with: | SMZ/TMP or quinolone; prophylaxis not recommended |
| E coli group = in developed countries | Enterohemorrhagic |
| E coli: most likely from: | undercooked beef; unpasteurized juice; spinach; in warm weather |
| V cholera MOA | activates adenylate cyclase (cAMP regulates Na & Cl absorpn/secretion) |
| E. histolytica | necrosis of lg intestine; tropical; abd pain, cramping, colitis; can be bloody/fevers; travelers, MSM |
| E coli group = most common in developing countries | Enteroinvasive |
| salmonella: 3 patterns | Enteric (typhoid) fever; gastroenteritis; bacteremia |
| Pre-formed toxins: organisms | S aureus; B Cereus; Clostridium Perfringens |
| Defn diarrhea | >3/day; 200 g or ml; loose/liquid consistency |
| Most common cause of BACTERIAL gastroenteritis | C. jejuni |
