DESCRIPTION 
Bowel movements characterized as frequent (> 3/day), loose, and watery owing to an infectious or toxin exposure
ETIOLOGY
- Viruses:
- Invasive bacteria:
- Campylobacter:
- Contaminated food or water, wilderness water, birds, and animals
- Most common bacterial diarrhea
- Gross or occult blood is found in 60–90%.
- Salmonella:
- Shigella:
- Vibrio parahaemolyticus:
- Raw and undercooked seafood
- Yersinia:
- Contaminated food (pork), water, and milk
- May present as mesenteric adenitis or mimic appendicitis
- Bacterial toxin:
- Escherichia coli:
- Staphylococcus aureus:
- Most common toxin-related disease
- Symptoms 1–6 hr after ingesting food
- Bacillus cereus:
- Classic source—fried rice left on steam tables
- Symptoms within 1–36 hr
- Clostridium difficile:
- Antibiotic-associated enteritis linked to pseudomembranous colitis
- Incubation period within 10 days of exposure or initiation of antibiotics
- Aeromonas hydrophila:
- Aquatic sources primarily
- Affects children < 3 yr of age
- Fecal leukocytes absent
- Cholera:
- Caused by enterotoxin produced by Vibrio cholerae
- Profuse watery stools with mucus (classic appearance of rice-water stools)
- Protozoa:
- Giardia lamblia:
- Most common cause of parasite gastroenteritis in North America
- High-risk groups: Travelers, children in day care centers, institutionalized people, homosexual men, and campers who drink untreated mountain water
- Cryptosporidium parvum:
- Commonly carried in patients with AIDS
- Entamoeba histolytica (entamebiasis):
- 5–10% extraintestinal manifestations (hepatic amebic abscess)
Pediatric Considerations
- Most are viral in origin and self-limited.
- Rotavirus accounts for 50%.
- Shigella: Infections associated with seizures
- Focus evaluation on state of hydration.
[Outline]
SIGNS AND SYMPTOMS
History
- Loose, watery bowel movements
- Bloody stools with mucus
- Abdominal pain and cramps, tenesmus, flatulence
- Fever, headache, myalgias
- Nausea, vomiting
- Dehydration, lethargy, and stupor
Physical Exam
- Dry mucous membranes
- Abdominal tenderness
- Perianal inflammation, fissure, fistula
ESSENTIAL WORKUP
- Digital rectal exam to determine presence of gross or occult blood
- Fecal leukocyte determination:
- Present with invasive bacteria
- Absent in protozoal infections, viral, toxin-induced food poisoning
DIAGNOSIS TESTS & INTERPRETATION
Lab
- CBC—indications:
- Significant blood loss
- Systemic toxicity
- Electrolytes, glucose, BUN, creatinine—indications:
- Stool culture—indications:
- Presence of fecal leukocytes
- Historical markers: Immunocompromised, travel, homosexual
- Public health: Food handler, day care or health care worker, institutionalized
- Blood cultures—indications:
- Suspected bacteremia or systemic infections
- Ill patients requiring admission
- Immunocompromised
- Elderly patients and infants
Imaging
Abdominal radiographs:
- No value unless obstruction or toxic megacolon suspected
DIFFERENTIAL DIAGNOSIS
[Outline]
PRE-HOSPITAL
- Difficult IV access with severe dehydration
- Avoid exposure to contaminated clothes or body substances.
INITIAL STABILIZATION/THERAPY
- ABCs
- IV fluid with 0.9% normal saline (NS) resuscitation for severely dehydrated
ED TREATMENT/PROCEDURES
- Oral fluids for mild dehydration (Gatorade/Pedialyte)
- IV fluids for:
- Hypotension, nausea and vomiting, obtundation, metabolic acidosis, significant hypernatremia or hyponatremia
- 0.9% NS bolus: 500 mL–1 L (peds: 20 mL/kg) for resuscitation, then 0.9% NS or D5W 0.45% NS (peds: D5W 0.25% NS) to maintain adequate urine output
- Bismuth subsalicylate (Pepto-Bismol):
- Antisecretory agent
- Effective clinical relief without adverse effects
- Kaolin-pectin (Kaopectate):
- Reduces fluidity of stools
- Does not influence course of disease
- Antimotility drugs: Diphenoxylate (Lomotil), loperamide (Imodium), paregoric, codeine:
- Appropriate in noninfectious diarrhea
- Initial use of sparse amounts to control symptoms in infectious diarrhea
- Avoid prolonged use in infectious diarrhea—may increase duration of fever, diarrhea, and bacteremia and may precipitate toxic megacolon
- Antibiotics for infectious pathogens:
MEDICATION
- Ampicillin: 500 mg (peds: 20 mg/kg/24h) PO or IV q6h
- TMP-SMX (Bactrim DS): 1 tab (peds: 8–10 mg TMP/40–50 mg SMX/kg/24h) PO or 4–5 mg/kg TMP IV BID
- Ceftriaxone: 1 g (peds: 50–75 mg/kg/12h) IM or IV q12h.
- Ciprofloxacin (quinolone): 500 mg PO or 400 mg IV q12h (> 18 yr)
- Doxycycline: 100 mg PO or 100 mg IV q12h
- Erythromycin: 500 mg (peds: 40–50 mg/kg/24h) PO QID
- Iodoquinol: 650 mg (peds: 30–40 mg/kg/24h not to exceed 2 g daily) PO TID
- Metronidazole: 250 mg (peds: 35 mg/kg/24h) PO TID (> 8 yr)
- Quinacrine: 100 mg (peds: 6 mg/kg/24h) PO TID
- Tetracycline: 500 mg PO or IV q6h
- Vancomycin: 125–500 mg (peds: 40 mg/kg/24h) PO q6h
[Outline]
DISPOSITION
Admission Criteria
- Hypotension, unresponsive to IV fluids
- Significant bleeding
- Signs of sepsis or toxicity
- Intractable vomiting or abdominal pain
- Severe electrolyte imbalance or metabolic acidosis
- Altered mental status
- Children with > 10–15% dehydration
Discharge Criteria
- Mild cases requiring oral hydration
- Dehydration responsive to IV fluids
Issues for Referral
Cases of prolonged diarrhea may be referred to a gastroenterologist for further workup.
FOLLOW-UP RECOMMENDATIONS
Since diarrhea is self-limiting, follow-up is optional.
[Outline]
- Denno DM, Shaikh N, Stapp JR, et al. Diarrhea etiology in a pediatric emergency department: A case control study. Clin Infect Dis. 2012;55:897–904.
- DuPont HL. Clinical practice. Bacterial diarrhea. N Engl J Med. 2009;361(16):1560–1569.
- Leffler DA, Lamont JT. Treatment of Clostridium difficile–associated disease. Gastroenterology. 2009;136:1899–1912.
- Mehal JM, Esposito DH, Holman RC, et al. Risk factors for diarrhea-associated infant mortality in the United States, 2005–2007. Pediatr Infect Dis J. 2012;31:717–721.
See Also (Topic, Algorithm, Electronic Media Element)
Gastroenteritis