Bacterial gastroenteritis

See Acute gastroenteritis (peds) for pediatric patients

Background

• Most acute gastroenteritis (AGE) is viral, not bacterial
• Bloody diarrhea suggests bacterial etiology
• Do NOT diagnose isolated vomiting as AGE

Clinical Features and Causes

Noninvasive AGE

Species	Onset	Symptoms	Transmission	Preformed Toxin
Viral (norovirus, adenovirus, rotavirus)	11-72 hrs	Nausea, vomiting, watery diarrhea Mild abdominal cramps, myalgia	Fecal-oral Contaminated food or water	No
Staph	1-6 hrs	Nausea, severe vomiting, diarrhea, Mild abdominal 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, abdominal 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, relative bradycardia Abdominal pain Bloody diarrhea Headache Osteomyelitis in sickle cell	Eggs Poultry Water Reptiles
Shigella	1-3 days	Fever Abdominal pain Bloody diarrhea Headache 1-5 years old Seizures in children	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 Guillain-Barre	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

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

Nausea and vomiting

Critical

• ACS/MI
• Boerhaave's
• DKA
• Intracranial hemorrhage
• Ischemic bowel
• Meningitis
• Sepsis

Emergent

• Acute radiation syndrome
• Acute gastric dilation
• Adrenal insufficiency
• Appendicitis
• Bowel obstruction/ileus
• Carbon monoxide poisoning
• Cholecystitis
• CNS tumor
• Electrolyte abnormalities
• Elevated ICP
• Gastric outlet obstruction, gastric volvulus
• Hyperemesis gravidarum
• Medication related
  • Acetaminophen toxicity
  • Aspirin toxicity
  • Digoxin toxicity
  • Theophylline toxicity
  • GLP-1 receptor agonist toxicity
• Pancreatitis
• Peritonitis
• Ruptured viscus
• Testicular torsion/ovarian torsion

Nonemergent

• Acute gastroenteritis
• Biliary colic
• Cannabinoid hyperemesis syndrome
• Chemotherapy
• Cyclic vomiting syndrome
• ETOH
• Gastritis
• Gastroenteritis
• Gastroparesis
• Hepatitis
• Labyrinthitis
• Migraine
• Medication related
  • Disulfiram effect
  • Erythromycin
  • Ibuprofen
  • Ipecac toxicity
• Motion sickness
• Narcotic withdrawal
• Thyroid
• Pregnancy
• Peptic ulcer disease
• Renal colic
• UTI

Evaluation

• Assess hydration status
  • Cap refill, skin turgor, respiratory rate
• Consider stool studies 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
   • Reduced-osmolarity oral rehydration solution
2. Antiemetic
   • Ondansetron 0.15mg/kg/dose IV/PO
3. Antibiotics
   • Only consider in patients with 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

• Acute gastroenteritis
• Nausea and Vomiting
• Acute gastroenteritis (peds)
• Dehydration
• Acute diarrhea