Acute diarrhea
Background
- Almost all true diarrheal emergencies are of noninfectious origin
- 85% of diarrhea is infectious in etiology
- Viruses cause vast majority of infectious diarrhea
- Bacterial causes are responsible for most cases of severe diarrhea
- Foreign travel assoc w/ 80% probability of bacterial diarrhea (see Traveler's Diarrhea)
- Definitions
- Diarrhea: Increased frequency of defection, usually >3 bowel movements per day
- Hyperacute: 1-6 hr
- Acute: less than 3 wks in duration
- Gastroenteritis: Diarrhea with nausea and/or vomiting
- Dysentery: Diarrhea with blood/mucus/pus
- Invasive = Infectious
Diagnosis
History
- Possible food poisoning?
- Symptoms occur within 6hr
- Does it resolve (osmotic) or persist (secretory) w/ fasting?
- Are the stools of smaller volume (large intestine) or larger volume (small intestine)
- Fever or abdominal pain? (diverticulitis, gastroenteritis, IBD)
- Bloody or melenic?
- Tenesmus? (shigella)
- Malodorous? (giardia)
- Recent travel?
- Recent Abx?
- HIV/immunocomp/sexual hx
- Heat intolerance and anxiety? (thyrotoxicosis)
- Paresthesias or reverse temperature sensation? (Ciguatera)
Physical Exam
- Thyroid masses
- Oral ulcers, erythema nodosum, episcleritis, anal fissure (IBD)
- Reactive arthritis (Arthritis, conjunctivitis, urethritis)
- Suggests infx w/ salmonella, shigella, campylobacter, or yersinia
- Rectal exam for fecal impaction
- Guaiac
- Abdominal pain out of proportion to exam (mesenteric ischemia)
Toxigenic v. Infectious
Characteristic | Toxic | Infectious/Invasive |
Incubation | 2-12h | 1-3d |
Onset | abrupt | gradual |
Duration | <10-24h | 1-7days |
Fever | No | Yes |
Abdominal Pain | Minimal | Yes, tenesmus |
Systemic | No | Yes, myalgias, N/V |
Physical findings | Nontoxic | Toxic |
Abdominal Tenderness | No | Yes |
Stool Blood, WBCs | No | Yes |
Differential Diagnosis
Acute diarrhea
Infectious
- Viral (e.g. rotavirus)
- Bacterial
- Campylobacter
- Shigella
- Salmonella (non-typhi)
- Escherichia coli
- E. coli 0157:H7
- Yersinia enterocolitica
- Vibrio cholerae
- Clostridium difficile
- Parasitic
- Toxin
Noninfectious
- GI Bleed
- Appendicitis
- Mesenteric Ischemia
- Diverticulitis
- Adrenal Crisis
- Thyroid Storm
- Toxicologic exposures
- Antibiotic or drug-associated
Watery Diarrhea
- Enterotoxigenic E. coli (most common cause of watery diarrhea)[1]
- Norovirus (often has prominent vomiting)
- Campylobacter
- Non-typhoidal Salmonella
- Enteroaggregative E. coli (EAEC)
- Enterotoxigenic Bacteroides fragilis
Traveler's Diarrhea
Work-Up
Indicated for:
- Profuse watery diarrhea w/ signs of hypovolemia
- Severe abdominal pain
- Fever >38.5 (101.3) (suggests infection w/ invasive bacteria)
- Symptoms >2-3d
- Blood or pus in stool (E. coli 0157:H7)
- Recent hospitalization or abx use
- Elderly or immunocompromised
- Systemic illness w/ diarrhea (esp if pregnant (listeria))
- Fecal leukocytes
- Used to differentiate invasive from noninvasive infectious diarrheas
- Sn 50-80%, Sp 83% for presence of bacterial pathogen
- If pt has +leukocytes but negative infection consider IBD
- Stool culture
- Plays minor role in ED evaluation
- Yield is only 1.5-5.5%
- Consider in pts w/:
- Immunosuppression
- Severe, inflammatory diarrhea (including bloody diarrhea)
- Underlying IBD (need to distinguish between flare and superimposed infection)
- O&P
- Indicated if parasitic cause is suspected:
- Diarrhea >7d
- Untreated water
- AIDS
- Bloody diarrhea w/ few or no fecal leukocytes (intestinal amebiasis)
- Indicated if parasitic cause is suspected:
- C. diff toxin
- 10% false negative rate
- Takes 24hr to run
- Chemistry
- Warranted in severely dehydrated pts
- Abd x-ray
- Consider if h/o abdominal sx (r/o obstruction)
- CXR
- Consider if diarrhea + cough (Legionella)
- CT
- Consider if suspect mesenteric ischemia
Treatment
- Oral rehydration
- Fluids should contain sugar, salt, and water
- Probiotics
- Lactobacilli and bifidobacterium
- 25% decrease in average duration of diarrhea (good evidence)
- Food
- Eat: BRAT diet (no evidence)
- Avoid: Caffeine (incr gastric motility), raw fruit (incr osmotic diarrhea), lactose
- Antibiotics
- Contraindications:
- Suspected or proven EHEC (e.g. O157:H7)
- Suspect if bloody diarrhea, abdominal pain, but little or no fever
- Suspected or proven EHEC (e.g. O157:H7)
- Indications:
- Suspected bacterial diarrhea
- Fever
- Bloody diarrhea (except for EHEC)
- Occult blood or +fecal leukocytes
- Moderate to severe travelers' diarrhea (>4 stools/d, fever, blood, or mucus in stool)
- >8 stools/d
- Volume depletion
- >1wk duration
- Immunocompromised
- Toxic appearance
- Suspected bacterial diarrhea
- Ciprofloxacin
- First-line choice for empiric therapy
- 500mg BID x 3-5d
- Azithromycin
- Use if fluroquinolone resistance is expected (e.g. Campylobacter from SE Asia)
- 500mg QD x3d
- Contraindications:
- Antimotility agents
- May mask amount of fluid lost (fluid may pool in the intestine); encourage rehydration
- Agents:
- Loperamide
- Most effective agent
- Dose: 4mg; then 2mg after each unformed stool for no more than 2d (max 16mg/d)
- Give w/ abx in pts w/ invasive infection
- Avoid in pts w/:
- Bloody diarrhea
- C. diff
- High fever
- Bismuth subsalicylate
- Consider when loperamide is contraindicated (high fever, dysentery)
- Dose: 30 mL or 2tab q30 min for 8doses; repeat on day 2
- Caution: may cause bismuth encephalopathy in HIV pts
- Diphenoxylate and atropine 4mg QID x2d
- 2nd line agent (may cause cholinergic side effects
- Loperamide
Disposition
- Conservatism should be the rule with the young and the elderly
See Also
Source
- Rosen's
- Tintinalli
- UpToDate
- ↑ Marx et al. “Cholera and Gastroenteritis caused by Noncholera Vibrio Species”. Rosen’s Emergency Medicine 8th edition vol 1 pg 1245-1246.