Gastrointestinal Emergencies
Pediatric abdominal complaints demand attention to age-specific diagnoses and to volume status. Vomiting and diarrhea cause most dehydration; classify dehydration clinically (mild under 5%, moderate 5–10%, severe over 10%) using mental status, mucous membranes, tears, capillary refill, skin turgor, and heart rate. Oral rehydration is first-line for mild to moderate dehydration; isotonic crystalloid boluses (20 mL/kg) are for severe dehydration or shock. Do not forget hypoglycemia and electrolyte derangement in the child who is lethargic after gastroenteritis.
Surgical emergencies
The highest-yield exam trap is bilious vomiting in a neonate - assume malrotation with volvulus until excluded; this is a surgical emergency. Compare with pyloric stenosis (2–6 weeks of age, projectile nonbilious vomiting, visible peristaltic wave, olive-shaped mass, hypochloremic hypokalemic metabolic alkalosis). Intussusception peaks at 6–36 months with episodic colicky pain, drawing up of the legs, lethargy, a sausage-shaped mass, and currant-jelly stool; air enema is both diagnostic and therapeutic. Appendicitis migrates from periumbilical pain to the right lower quadrant with anorexia, low-grade fever, and guarding; perforation is common in children under 5 because presentation is atypical.
Other presentations
Bloody diarrhea with cramping should raise concern for hemolytic uremic syndrome (Shiga-toxin E. coli) - avoid antimotility agents and monitor renal function and blood counts. Hematemesis or melena requires hemodynamic assessment and large-bore access. Foreign body and caustic ingestions require poison control consultation; button batteries in the esophagus are emergent, and magnetic objects need surgical review.
Rule of thumb: bilious emesis, rigid abdomen, or absent bowel sounds equals a surgical consult, not a workup delay.