Gastrointestinal (GI) problems in children range from harmless infant spitting to surgical emergencies. Age and the color of vomitus are the first clues. Children also dehydrate much faster than adults because more of their body weight is water and their daily fluid turnover is high (see "Fluid and Electrolyte Imbalances in Children"). Neonatal anomalies (pyloric stenosis, Hirschsprung disease, atresias, NEC) are covered in Unit 3; this topic focuses on problems of infancy and childhood and how to tell them apart.

Key rule: bilious (green) vomiting in an infant is a surgical emergency until proven otherwise — it means obstruction below the ampulla of Vater. In the first days of life the causes are intestinal atresia (duodenal, jejunal, ileal) and malrotation with midgut volvulus, which can cut off blood supply to the whole small bowel within hours.

Priority assessments for any vomiting or diarrhea: hydration status (weight, mucous membranes, tears, fontanel, capillary refill, urine output), color and force of vomitus, stool character, abdominal distension, and pain behavior.

Malrotation with volvulus — emergency surgery (Ladd procedure); NG decompression, IV fluids, and antibiotics while preparing.

Intussusception

• First-line: air (pneumatic) or saline (hydrostatic) enema reduction under imaging guidance — succeeds in most children
• Surgery if the enema fails or with peritonitis, perforation, or shock (enema is contraindicated)
• Recurrence can occur, most often within the first days

Appendicitis

• NPO, IV fluids, IV antibiotics (e.g., ceftriaxone plus metronidazole, or piperacillin-tazobactam), analgesia, then appendectomy (usually laparoscopic)
• Perforated appendicitis: longer IV antibiotic course; possible drain
• Nonoperative antibiotic treatment is an option for selected uncomplicated cases at some centers
• Pain medicine does not mask the diagnosis and should not be withheld

GER / GERD

• GER: reassurance; no medicine
• GERD: smaller, more frequent feeds, avoiding overfeeding, thickened feeds, and a 2–4 week trial of eliminating cow's milk protein (maternal diet or hydrolyzed formula) before medication
• Acid suppression (PPI or H₂ blocker) is not used for simple infant reflux; reserved for proven erosive esophagitis; older children and adolescents with typical heartburn may have a 4–8 week PPI trial
• Surgery (fundoplication) is rare

Celiac disease — strict lifelong gluten-free diet: avoid wheat, barley, rye, and foods contaminated with them; rice, corn, potatoes, and pure uncontaminated oats (in most) are allowed. Correct iron, folate, vitamin D, and calcium deficiencies. Dietitian referral.

Functional constipation — disimpaction, then maintenance polyethylene glycol (PEG 3350) as first-line, with scheduled toilet sitting and adequate fluid and fiber. Stimulant laxatives short term; enemas only if oral treatment fails.

Acute gastroenteritis — oral rehydration and continued feeding; antibiotics only for specific bacterial or parasitic causes; no routine antidiarrheal drugs.

Drug safety (doses weight-based and verified against a pediatric reference)

Listed in priority order.

1. Recognize surgical emergencies
   • Bilious vomiting, abdominal distension, bloody stools, or signs of shock: keep NPO, notify the provider immediately, insert NG tube as ordered, start IV access and fluids
   • Signs of perforation or peritonitis: rigid abdomen, sudden relief of pain then fever, tachycardia, lethargy
2. Circulation and hydration
   • Assess hydration; weigh daily on the same scale; strict intake and output (weigh diapers: 1 g = 1 mL)
   • IV fluids by infusion pump; monitor electrolytes and glucose
3. Pre-procedure and preoperative care
   • Intussusception: monitor pain, vital signs, and stools; report passage of a normal brown stool (the intussusception may have reduced on its own — the plan may change)
   • Appendicitis: keep NPO; give IV antibiotics and analgesics as ordered; position of comfort (often right side-lying or semi-Fowler's); no heat to the abdomen, no laxatives or enemas (can cause rupture)
   • Prepare the child with age-appropriate explanations; involve parents
4. Postoperative care
   • Pain assessment with age-appropriate scale; early ambulation; monitor bowel sounds, return of flatus, and wound
   • Perforated appendix: wound and drain care, IV antibiotics, watch for abscess (recurrent fever, pain)
5. Feeding and nutrition
   • GER: hold the infant upright during feeds and burp frequently; hold upright 20–30 minutes after feeds while awake
   • Safe sleep: infants with reflux still sleep on the back on a flat, firm surface — no wedges, no prone or side positioning
   • Celiac: check labels and meal choices with the family
6. Infection control — contact precautions for diarrhea in diapered or incontinent children; hand washing with soap and water (alcohol gel is less effective against norovirus and does not kill C. difficile spores)

• Seek care immediately for green vomiting, blood in stool, a swollen or hard abdomen, repeated episodes of severe pain with drawing up of the legs, or a lethargic child
• GER is normal in a thriving infant and usually resolves by 12–18 months; avoid overfeeding; do not put the infant to sleep on the stomach or on an incline
• Celiac disease: gluten-free for life; read labels for wheat, barley, rye, malt, and hidden gluten in sauces, soups, and medicines; use separate toasters and utensils; inform school; a gluten-free diet also lowers the long-term risk of complications such as lymphoma
• Constipation: daily scheduled toilet sitting 5–10 minutes after meals, foot support, praise (no punishment), fluids, fruit, vegetables, whole grains, and continuing PEG for months as prescribed
• After appendectomy: gradual return to activity; avoid heavy lifting and contact sports for the period advised by the surgeon; report fever, increasing pain, vomiting, or wound redness
• Hand washing after toileting and diaper changes; rotavirus vaccine protects infants

• Bilious vomiting in an infant = surgical emergency (malrotation with volvulus or atresia) — NPO, notify, upper GI study
• Projectile non-bilious vomiting at 2–8 weeks with an olive-shaped mass = pyloric stenosis
• Intussusception: 3 months to 3 years, colicky pain with knees to chest, currant jelly stool, sausage mass, target sign on ultrasound; first-line air or saline enema; report a normal brown stool before the procedure
• Hirschsprung disease: delayed meconium beyond 48 hours; explosive stool after rectal exam (see Unit 3)
• Appendicitis: periumbilical pain moving to the right lower quadrant; NPO before surgery; no heat, laxatives, or enemas; analgesia is appropriate; sudden relief of pain = perforation
• Obstruction on X-ray: dilated loops with air-fluid levels
• Celiac disease: steatorrhea, poor growth, villous atrophy; lifelong gluten-free diet (no wheat, barley, rye)
• GER in a thriving infant needs no drugs; infants with reflux still sleep supine
• No antidiarrheal drugs or bismuth subsalicylate for young children
• Constipation: PEG 3350 first-line plus scheduled toileting