Treatment of Infectious Gastroenteritis

Assessment and Rehydration

The American Academy of Pediatrics and the World Health Organization recommend oral rehydration therapy (ORT) with reduced osmolarity oral rehydration solution (ORS) as the first-line approach for mild to moderate dehydration in both children and adults 1, 2
Evaluate hydration status through physical examination looking for specific signs including decreased skin turgor, dry mucous membranes, sunken eyes, altered mental status, tachycardia, and decreased urine output 1
Categorize dehydration as:
- Mild: <4% body weight loss 1
- Moderate: 4-6% body weight loss 1
- Severe: >6% body weight loss 1
For mild to moderate dehydration, provide oral rehydration solution (ORS) as first-line therapy, with a dosage of 50-100 mL/kg over 3-4 hours for infants and children, and 2-4 L for adolescents and adults 1, 2
Use commercially available low-osmolarity ORS (e.g., Pedialyte, CeraLyte) for rehydration 1, 2
Avoid apple juice, sports drinks like Gatorade, and commercial soft drinks as primary rehydration solutions as they may have inappropriate electrolyte and sugar content 1

Continue breastfeeding throughout the diarrheal episode in infants 1
Resume age-appropriate diet during or immediately after rehydration 1
Avoid fasting or withholding food for prolonged periods as this does not improve outcomes and may worsen nutritional status 1, 3
Avoid foods high in simple sugars (soft drinks, undiluted apple juice, Jell-O, presweetened cereals) which can exacerbate diarrhea through osmotic effects 3

The Infectious Diseases Society of America recommends that empiric antimicrobial therapy for infectious gastroenteritis is generally not recommended in immunocompetent children and adults 2, 4
Exceptions where empiric antimicrobial therapy should be considered include infants <3 months of age with suspected bacterial etiology, patients with fever, abdominal pain, bloody diarrhea, and bacillary dysentery presumptively due to Shigella 2, 5
When antimicrobial therapy is indicated, the American College of Gastroenterology recommends fluoroquinolone (e.g., ciprofloxacin) or azithromycin for adults, and third-generation cephalosporin or azithromycin for children 2, 5
Avoid antimicrobial therapy for STEC O157 and other STEC that produce Shiga toxin 2 as it may increase the risk of hemolytic uremic syndrome 2, 5

The Centers for Disease Control and Prevention recommend that immunocompromised people with severe illness and bloody diarrhea should receive empiric antibacterial treatment 2, 5
Pregnant women with Salmonella gastroenteritis should receive treatment to prevent extraintestinal spread, with choices including ampicillin, cefotaxime, ceftriaxone, or TMP-SMZ 7

Practice proper hand hygiene after using toilet, changing diapers, before/after food preparation, and after handling animals 1
Use infection control measures including gloves, gowns, and hand hygiene with soap and water when caring for patients with diarrhea 1
Asymptomatic contacts of people with bloody diarrhea should not be offered empiric treatment but should follow appropriate infection prevention measures 2, 5