Gastroenteritis, Emergency Medicine

Basics

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:
  - Typhoid fever (Salmonella typhi) characterized by unremitting fever, abdominal pain, rose spots, splenomegaly, and bradycardia
  - Immunocompromised susceptible
- Shigella: Fecal-oral route
- Vibrio parahaemolyticus: Raw and undercooked seafood
- Yersinia: Contaminated food (pork), water, and milk:
  - May present as mesenteric adenitis or mimic appendicitis
- 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)

Focus evaluation on state of hydration
Most of viral origin and self-limited
Rotavirus accounts for up to 50%
Shigella infections associated with seizures

Diagnosis

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:
- Lethargy, significant dehydration, toxicity, or altered mental status
- Diuretic use, persistent diarrhea, chronic liver or renal disease
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.

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

Gastritis/peptic ulcer disease
Milk and food allergies
Appendicitis
Irritable bowel syndrome
Ulcerative colitis/Crohns disease
Malrotation with midgut volvulus
Meckel diverticulum
Drugs and toxins:
- Mannitol
- Sorbitol
- Phenolphthalein
- Magnesium-containing antacids
- Quinidine
- Colchicine
- Mushrooms
- Mercury poisoning

Treatment

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:
- Campylobacter: Quinolones or erythromycin
- Salmonella: Quinolones or trimethoprim-sulfamethoxazole (TMP-SMX)
- Typhoid fever: Ceftriaxone
- Shigella: Quinolone, TMP-SMX, or ampicillin
- V. parahaemolyticus:Tetracycline or doxycycline
- Clostridium difficile: Metronidazole or vancomycin
- Escherichia coli: Quinolones or TMP-SMX
- Giardia lamblia: Metronidazole
Antiemetics for nausea/vomiting:
- Ondansetron
- Prochlorperazine
- Promethazine

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

Follow-Up

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.

Followup Recommendations

Most cases are self-limiting; therefore, follow-up is optional.

Pearls and Pitfalls

Viruses account for over 50% of cases
Avoid antimotility drugs in cases due to infectious pathogens.
TMP-SMX (Bactrim DS), ciprofloxacin, doxycycline, and tetracycline are contraindicated in pregnancy. Metronidazole may be used during the 3rd trimester.

Additional Reading

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.

Codes

ICD9

008.63 Enteritis due to norwalk virus
009.0 Infectious colitis, enteritis, and gastroenteritis
558.9 Other and unspecified noninfectious gastroenteritis and colitis
008.43 Intestinal infection due to campylobacter
003.0 Salmonella gastroenteritis
004.9 Shigellosis, unspecified
008.44 Intestinal infection due to yersinia enterocolitica

ICD10

A08.11 Acute gastroenteropathy due to Norwalk agent
A09 Infectious gastroenteritis and colitis, unspecified
K52.9 Noninfective gastroenteritis and colitis, unspecified
A04.5 Campylobacter enteritis
A02.0 Salmonella enteritis
A03.9 Shigellosis, unspecified
A04.6 Enteritis due to Yersinia enterocolitica

SNOMED

25374005 Gastroenteritis (disorder)
12463005 Infectious gastroenteritis (disorder)
24789006 Viral gastroenteritis due to Norwalk-like agents
18081009 enteric campylobacteriosis (disorder)
111817006 Infection by Shigella (disorder)
240334006 Yersinia enterocolitica food poisoning (disorder)
42338000 Salmonella gastroenteritis (disorder)

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