Gastroenteritis - Bacterial

Definition

Bacterial gastroenteritis in children is an acute inflammation of the stomach and intestines caused by pathogenic bacteria, leading to diarrhea, vomiting, abdominal pain, and systemic symptoms such as fever and dehydration.

Epidemiology

• Common cause of acute diarrhea in children worldwide
• Higher prevalence in low- and middle-income countries due to poor sanitation
• Peak incidence in children under 5 years of age
• Seasonal variation: more common during warmer months
• Transmission primarily via fecal-oral route

Etiology

• Common bacterial pathogens: Salmonella, Shigella, Escherichia coli (EHEC, ETEC), Campylobacter, Vibrio cholerae
• Foodborne outbreaks from contaminated food or water
• Antibiotic-associated infections leading to Clostridioides difficile colitis
• Nosocomial infections in hospitalized children
• Underlying immunodeficiency increases susceptibility

Pathophysiology

• Bacteria adhere to and invade intestinal epithelium, releasing toxins
• Toxins cause secretory diarrhea by increasing intestinal fluid secretion
• Invasive bacteria lead to mucosal inflammation, ulceration, and bloody diarrhea
• Inflammation triggers immune response, leading to fever and systemic symptoms
• Fluid and electrolyte loss results in dehydration and electrolyte imbalances
• Severe infections can lead to bacteremia or hemolytic uremic syndrome (HUS)