Gastroenteritis Overview

Gastroenteritis

• Gastroenteritis is inflammation of the stomach and intestines.
• It's categorized as acute, persistent, or chronic.
• Viruses, bacteria, parasites, and non-infectious causes can trigger Gastroenteritis.

Etiology

• Norovirus and Rotavirus are common viral causes.
• Bacteria like E. coli, Clostridium species, Salmonella, Shigella, Giardia and Entamoeba are also causes.
• Non-infectious causes include toxins or irritants.

Transmission

• Transmission occurs through contaminated food, water, surfaces or person-to-person contact (especially airborne viral particles from vomitus).

Epidemiology

• Gastroenteritis, especially the acute form, is often linked to food or water contamination.
• Acute, chronic, and persistent forms of the disease have varying degrees of severity.

Pathogenesis - Bacterial Gastroenteritis

• Bacteria can produce toxins in food before ingestion (staphylococcus).
• Bacteria can produce toxins in the gastrointestinal tract (C. perfringens, Enterotoxigenic E. coli).
• Bacteria can invade the intestinal wall causing inflammatory diarrhea (Shiga toxin producing bacteria like enterohemorrhagic E. coli).
• Factors like undercooked meat, untreated milk can contribute to this type.
• No antibiotic treatment is generally recommended for EHEC infections.
• Clostridium difficile causes diarrhea which may be associated with antibiotic treatment.

Pathogenesis - Viral Gastroenteritis

• Viruses disrupt the brush border enzyme production in enterocytes leading to malabsorption and osmotic diarrhea.
• Viral toxins can lead to cell lysis and fluid loss, causing significant electrolyte imbalances.
• Viruses are shed in feces and sometimes vomitus. Symptoms typically peak 24-48 hours after infection.

Clinical Manifestations

• Key symptoms include vomiting, diarrhea, abdominal cramping, fever, and blood in stool.

Complications

• Dehydration and electrolyte imbalances are common complications.
• Hemolytic uremic syndrome (HUS) is one possible severe complication linked to Shiga toxin producing bacteria like EHEC.

Management Principles

• Most cases are self-limiting.
• Supportive care, including hydration strategies, are common.
• Antibiotic use is guided based on bacterial cause.
• Public health measures (like hygiene practices, sanitation, and food safety) are often part of prevention and containment.
• Vaccinations may reduce incidence in some populations.