Acute gastroenteritis

Background

• Blood diarrhea suggests bacterial etiology
• Viral AGE usually lasts <7d
• Do not dx isolated vomiting as AGE

Causes

Noninvasive AGE

Species	Onset	Symptoms	Transmisison	Preformed Toxin
Viral (norovirus, adenovirus, rotavirus)	11-72 hrs	Nausea, vomiting, watery diarrhea Mild abd cramps, myalgia	Fecal-oral Contaminated food or water	No
Staph	1-6 hrs	Nausea, severe vomiting, diarrhea, Mild abd cramping	Previously cooked foods (mayonaise, ham, salads)	Yes
B. cereus	1-6 hrs	Abrupt onset of nausea, vomiting, mild diarrhea	Previously cooked foods (rice, vegetables, dried fruits, meat)	Yes
C. perfringens	8-24 hrs	Nausea, minimal vomiting, watery diarrhea Abd cramps	Previously cooked or reheated meats and poultry	Yes
V. cholerae	11-72 hrs	Explosive rice-water diarrhea Vomiting, abd cramps Fever	Fecal-oral Contaminated food or water	No
Giardia	1-4 wks	Flatus, bloating Foul-smelling and fatty stools (steatorrhea)	Fecal-oral Contaminated water	No

Invasive AGE

Species	Onset	Symptoms	Transmission
Salmonella	6-72 hours	Fever Abdominal pain Headache	Eggs Poultry Water Reptiles
Shigella	1-3 days	Fever Abdominal pain Headache 1-5 years old	Food Fecal-Oral
Yersinia	1-5 days	Appendicitis mimic, RLQ pain Fever Vomiting Kids and Young Adults	Water Milk Pork Wild Animals Fecal-Oral
Campylobacter	1-7 days	Low grade fever Abdominal pain Kids and Young Adults	Water Poultry Pets/Animals
C. Diff	1-11 Weeks	Copious FOUL diarrhea	Antibiotic use: PCN, Clinda, Cephalosporins
Entamoeba	1-11 weeks	Appendicitis Mimic Abdominal pain, nausea/vomiting, diarrhea	Water Sanitation Travel

Clinical Features

• Vomiting/diarrhea
• Crampy/diffuse abdominal pain

Differential Diagnosis

Diffuse Abdominal pain

• Abdominal aortic aneurysm
  • Aortocaval fistula
• Acute gastroenteritis
• Aortoenteric fisulta
• Appendicitis (early)
• Bowel obstruction
  • Large bowel obstruction
    • Ogilvie's syndrome
  • Small bowel obstruction
  • Malignant bowel obstruction
• Bowel perforation
• Diabetic ketoacidosis
• Gastroparesis
• Hernia
• Hypercalcemia
• Inflammatory bowel disease
• Mesenteric ischemia
  • Mesenteric vein thrombosis
• Pancreatitis
• Peritonitis
• Sickle cell crisis
• Spontaneous bacterial peritonitis
• Volvulus

Diagnosis

• Assess hydration status
  • Cap refill, skin turgor, resp rate
• Consider stool labs if:
  • >10 stools in previous 24hr
  • Travel to high-risk country
  • Fever
  • Bloody stool
  • Persistent diarrhea

Management

1. Rehydration (PO preferred)
   • 30mL(1oz)/kg/hr
2. Antiemetic
   • Ondansetron 0.15mg/kg/dose IV/PO
3. Antibiotics
   • Only consider in pts w/ invasive infection
     • Shigella, campylobacter, E. coli, yersinia, vibrio
     • Bloody stool with mucus and fever
   • NOT indicated for E. coli O157:H7
   • NOT routinely indicated for salmonella
     • Exceptions: SCD, IBD, <3mo
   • Azithromycin (able to tolerate PO)
   • OR ciprofloxacin
   • OR TMP-SMX
   • Ceftriaxone (parenteral)

Disposition

• Most can be discharged
• Admit
  • Unable to tolerate PO
  • Hemodynamic instability
  • Significant comorbidities

See Also

• Nausea and Vomiting
• Diarrhea (Peds)
• Dehydration
• Acute diarrhea