What is the diagnosis and treatment for Gastroenteritis?

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Last updated: April 22, 2025View editorial policy

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From the Guidelines

For patients with gastroenteritis, oral rehydration therapy using reduced osmolarity oral rehydration solutions (ORS) is the recommended first-line therapy for mild to moderate dehydration in infants, children, and adults, as it has been shown to be effective in reducing morbidity and mortality 1.

Key Recommendations

  • Oral rehydration therapy should be initiated as soon as possible, with the goal of correcting dehydration within 3-4 hours.
  • The recommended ORS solution is a reduced osmolarity solution, which can be given to all age groups, with any cause of diarrhea.
  • For infants and children, the recommended dose is 50-100 mL/kg over 3-4 hours, while for adolescents and adults, the recommended dose is 2-4 L.
  • Nasogastric administration of ORS may be considered in infants, children, and adults with moderate dehydration who cannot tolerate oral intake.

Management of Dehydration

  • For mild to moderate dehydration, ORS is the preferred treatment, while for severe dehydration, intravenous isotonic crystalloid boluses should be administered until pulse, perfusion, and mental status return to normal.
  • Once the patient is rehydrated, maintenance fluids should be administered, and ongoing losses in stools should be replaced with ORS until diarrhea and vomiting are resolved.

Antibiotic Therapy

  • Antibiotics may be considered in cases of severe travelers' diarrhea, dysentery, or moderate to severe acute bacterial diarrhea, with azithromycin being the recommended first-line agent due to its efficacy and safety profile 1.
  • The choice of antibiotic should be based on the severity of illness, regional patterns of probable target pathogens, and their antimicrobial resistance.

Prevention

  • Handwashing and food safety practices are essential for prevention, as gastroenteritis spreads easily through contaminated food, water, or person-to-person contact.
  • Breastfed infants should continue nursing throughout the illness, and children previously receiving a lactose-containing formula can tolerate the same product in most instances.

From the Research

Definition and Epidemiology

  • Acute gastroenteritis is defined as a diarrheal disease of rapid onset, with or without nausea, vomiting, fever, or abdominal pain 2.
  • In the United States, acute gastroenteritis accounts for 1.5 million office visits, 200,000 hospitalizations, and 300 deaths in children each year 2.
  • Approximately 178 million cases of acute gastroenteritis occur annually in the United States, resulting in 473,000 hospitalizations and 5000 deaths 3.

Diagnosis and Evaluation

  • Evaluation of a child with acute gastroenteritis should include a recent history of fluid intake and output 2.
  • The physical examination is the best way to evaluate hydration status, and the four-item Clinical Dehydration Scale can be used to determine severity of dehydration based on physical examination findings 2.
  • In children with mild illness, stool microbiological tests are not routinely needed when viral gastroenteritis is the likely diagnosis 2.

Treatment and Management

  • Oral rehydration therapy is the mainstay of treatment for mild dehydration and is as effective as intravenous rehydration for preventing hospitalization and return to the emergency department 2, 4.
  • Oral rehydration solutions are recommended for moderate dehydration, and ondansetron may be prescribed if needed to prevent vomiting and improve tolerance of oral rehydration solutions 2.
  • Hospitalization and intravenous fluids are recommended for children who do not respond to oral rehydration therapy plus an antiemetic and patients with severe dehydration 2.
  • Antibiotics may be indicated in certain cases of acute gastroenteritis, and guidelines have been developed to promote appropriate antibiotic use and prevent antibiotic resistance 5.

Prevention

  • Handwashing, breastfeeding, and rotavirus vaccination can reduce the incidence of acute gastroenteritis in young children 2.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Gastroenteritis in Children.

American family physician, 2019

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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