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DigestiveICD-10: K52.9Causes approximately 19-21 million cases of illness in the U.S. annually

Gastroenteritis (Stomach Flu)

Also known as: Stomach Flu, Stomach Bug, Viral Gastroenteritis, Gastric Flu

Gastroenteritis is an inflammation of the stomach and intestines typically caused by viral or bacterial infection, resulting in diarrhea, vomiting, abdominal cramps, and sometimes fever. Despite being commonly called the 'stomach flu,' it is not caused by influenza viruses; the most common culprits are norovirus and rotavirus. Gastroenteritis is highly contagious and is one of the leading causes of illness worldwide, with dehydration being the primary concern, especially in young children, older adults, and immunocompromised individuals.

Symptoms

Watery diarrhea, usually non-bloody
Nausea and vomiting
Abdominal cramps and pain
Low-grade fever
Headache and muscle aches
Loss of appetite
Signs of dehydration: dry mouth, decreased urination, dizziness

Causes

  • Norovirus (leading cause in adults)
  • Rotavirus (leading cause in children before vaccination)
  • Bacterial pathogens (Salmonella, E. coli, Campylobacter)
  • Parasitic infections (Giardia, Cryptosporidium)
  • Contaminated food or water ingestion

Risk Factors

  • Close contact with infected individuals in schools, daycares, or nursing homes
  • Consuming contaminated food or water
  • Weakened immune system
  • Young children and older adults are most vulnerable to severe illness
  • Living in crowded conditions or institutional settings
  • Travel to areas with poor sanitation

Diagnosis

  • Clinical diagnosis based on symptoms and history of exposure
  • Stool tests to identify specific viral, bacterial, or parasitic pathogens
  • Rapid antigen tests for norovirus or rotavirus
  • Blood tests to assess dehydration and electrolyte imbalances

Treatment

  • Oral rehydration therapy with electrolyte solutions
  • Gradual reintroduction of bland foods as tolerated
  • Anti-nausea medications (ondansetron) for severe vomiting
  • Intravenous fluids for severe dehydration requiring hospitalization
  • Antibiotics only for confirmed bacterial gastroenteritis
  • Rest and avoidance of dairy, caffeine, and fatty foods during recovery

Prevention

  • Wash hands frequently with soap and water, especially after using the bathroom
  • Disinfect contaminated surfaces with bleach-based cleaners
  • Avoid preparing food for others while symptomatic and for 48 hours after recovery
  • Ensure rotavirus vaccination for infants as recommended
  • Practice safe food handling and proper cooking temperatures

When to See a Doctor

  • Vomiting or diarrhea persists for more than 2 days in adults
  • You are unable to keep liquids down for 24 hours
  • You notice blood in your vomit or stool
  • Signs of severe dehydration develop: extreme thirst, very dark urine, confusion

Frequently Asked Questions

Related Conditions

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Medical Disclaimer: This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.

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