DESCRIPTION 
Inflammation of stomach and intestines associated with diarrhea and vomiting; often the result of infectious or toxin exposure.
ETIOLOGY
Infectious
- Viruses:
- 50–70% of all cases with Norovirus cases on the rise in travelers returning from Mexico and India.
- Invasive bacteria:
- Campylobacter: Contaminated food or water, wilderness water, birds, and animals:
- Most common cause
- Gross or occult blood is found in 60–90%.
- Salmonella: Contaminated water, eggs, poultry, or dairy products:
- Shigella: Fecal–oral route
- Vibrio parahaemolyticus: Raw and undercooked seafood
- Yersinia: Contaminated food (pork), water, and milk:
- Specific food-borne disease (food poisoning):
- Staphylococcus aureus:
- Most common toxin-related disease
- Symptoms within 1–6 hr after ingesting food
- Bacillus cereus:
- Classic source is fried rice left on steam tables.
- Symptoms within 1–36 hr
- Cholera: Profuse watery stools with mucous (rice-water stools)
- Ciguatera:
- Fish intoxication
- Onset 5 min–30 hr (average 6 hr) after ingestion
- Paresthesias, hypotension, peripheral muscle weakness
- Amitriptyline may be therapeutic.
- Scombroid:
- Caused by blood fish: Tuna, albacore, mackerel, and mahi-mahi
- Flushing, headache, erythema, dizziness, blurred vision, and generalized burning sensation
- Symptoms last < 6 hr.
- Treatment includes antihistamines.
- Protozoa:
- Giardia lamblia:
- High-risk groups: Travelers, day care children, homosexual men, and campers who drink untreated mountain water
Noninfectious Causes
- Toxins:
- Zinc, copper, cadmium
- Organic chemicals: Polyvinyl chlorides
- Pesticides: Organophosphates
- Radioactive substances
- Alkyl mercury
- Altered host response to food substance (tyramine, monosodium glutamate, tryptamine)
Pediatric Considerations
- Focus evaluation on state of hydration
- Most of viral origin and self-limited
- Rotavirus accounts for up to 50%
- Shigella infections associated with seizures
[Outline]
SIGNS AND SYMPTOMS
History
- Nausea, vomiting, diarrhea
- Bloody/mucous diarrhea
- Abdominal cramps or pain
- Fever
- Malaise, myalgias, headache, anorexia
- Hypotension, lethargy, and dehydration (severe cases)
Physical Exam
- Dry mucous membranes
- Tachycardia
- 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/health care worker)
- Blood culture indications:
- Suspected bacteremia or systemic infections
- Ill patients requiring admission
- Immunocompromised
- Elderly patients and infants
Imaging
Abdominal radiographs have no value unless obstruction or toxic megacolon suspected.
Pediatric Considerations
- Lab studies not required in most cases
- Rotazyme assay detects rotavirus:
- Rarely indicated in managing outpatients
- Helpful to cohort and avoid cross-contamination among inpatients
- Stool culture indication:
- Fecal leukocytes
- Toxic
- Infants
- Immunocompromised
DIFFERENTIAL DIAGNOSIS
[Outline]
PRE-HOSPITAL
- Difficult IV access with severe dehydration.
- Avoid exposure to contaminated clothes or body substances.
INITIAL STABILIZATION/THERAPY
- Management of ABCs
- IV fluid with 0.9% 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 (adults: 500 mL–1 L, peds: 20 mL/kg) for resuscitation, then 0.9% NS or D5 0.45% peds: NS (peds: D5 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, and 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:
- Antiemetics for nausea/vomiting:
MEDICATION
- Ampicillin: 500 mg (peds: 20 mg/kg/24 h) PO or IV q6h
- TMP–SMX; Bactrim DS: 1 tab (peds: 8–10 mg TMP/40–50 mg SMX/kg/24 h) PO BID
- Ceftriaxone: 1 g (peds: 50–75 mg/kg/12 h) IM or IV q12h
- Ciprofloxacin (quinolone): 500 mg PO or 400 mg IV BID (> 18 yr)
- Doxycycline: 100 mg PO or 400 mg IV BID
- Metronidazole: 250 mg (peds: 35 mg/kg/24 h) PO TID (> 8 yr)
- Ondansetron 4 mg (peds: 0.1 mg/kg) IV
- Prochlorperazine (Compazine): 5–10 mg IV q3–4h; 10 mg PO q8h; 25 mg per rectum (PR) q12h
- Promethazine (Phenergan): 25 mg IM/IV q4h; 25 mg PO/PR (peds: 0.25–1 mg/kg PO/PR/IM)
- Tetracycline: 500 mg PO or IV QID
- Vancomycin 125–500 mg (peds: 40 mg/kg/24 h) PO q6h
[Outline]
DISPOSITION
Admission Criteria
- Hypotension unresponsive to IV fluids
- Significant bleeding
- Signs of sepsis/toxicity
- Intractable vomiting or abdominal pain
- Severe electrolyte imbalance
- 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 symptoms may be referred to a gastroenterologist for further workup.
FOLLOW-UP RECOMMENDATIONS
Most cases are self-limiting; therefore, follow-up is optional.
[Outline]
- Bresee JS, Marcus R, Venezia RA, et al. The etiology of severe acute gastroenteritis among adults visiting emergency departments in the United States. J infect Dis. 2012;205:1374–1381.
- Centers for Disease Control and Prevention (CDC). Vital signs: Incidence and trends of infection with pathogens transmitted commonly through food–foodborne diseases active surveillance network, 10 U.S. sites, 1996–2010. MMWR Morb Mortal Wkly Rep. 2011;60:749–755.
- DuPont HL. Clinical practice. Bacterial diarrhea. N Engl J Med. 2009;361(16):1560–1569.
- Hill DR, Ericsson CD, Pearson RD, et al. The practice of travel medicine: Guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2006;43:1499–1539.
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