Pediatric GI: Pyloric Stenosis, Intussusception, Hirschsprung Disease (Pediatrics)

Prepared for Pass the Shift (owner: Kristina, RN). Always follow your facility’s protocols, provider orders, and current references.

1. Overview

Three structural GI conditions show up again and again on pediatric exams because each has a signature presentation. Learn the “picture,” then the priority (usually fluids/electrolytes and recognizing obstruction or perforation).


What	Thickened pyloric muscle blocks stomach emptying	Bowel telescopes into itself (often ileum into colon)	Missing nerve cells ( segment) in the distal colon → no peristalsis there
Age	~2–8 weeks; more common in first-born males	3 months – 3 years (peak 5–9 mo)	Newborn (most); milder cases later
Hallmark	Projectile, non-bilious vomiting after feeds; hungry after vomiting; olive-shaped mass	Sudden colicky pain (draws knees up), “currant jelly” stool, sausage-shaped mass	No meconium in first 24–48 h; abdominal distension; ribbon-like, foul stools in older child
Main danger	Dehydration, metabolic alkalosis, hypokalemia	Bowel ischemia, perforation, shock	Enterocolitis (fever, explosive diarrhea, distension) — life-threatening
Treatment	Pyloromyotomy (after fluid/electrolytes corrected)	Air or contrast enema (diagnostic and therapeutic); surgery if fails or perforated	Surgical removal of the aganglionic segment (pull-through); sometimes temporary ostomy

2. Pyloric Stenosis

Pathophysiology: the pyloric sphincter muscle thickens over the first weeks of life, progressively blocking the outlet. Vomiting stomach contents loses hydrochloric acid (H⁺ and Cl⁻) → hypochloremic, hypokalemic .

Signs: vomiting that becomes projectile, non-bilious (formula/milk only — the blockage is above the bile duct), hungry right after vomiting, weight loss, dehydration, fewer stools, visible peristaltic waves left to right, palpable olive-shaped mass in the RUQ/epigastrium.

Diagnostics: ultrasound (thickened, elongated pylorus); labs: low Cl⁻, low K⁺, high HCO₃⁻ (ranges vary).

Preoperative nursing:

Correct dehydration and electrolytes first — surgery waits until alkalosis and K⁺ are corrected (anesthesia risk: postoperative apnea with alkalosis)
NPO, IV fluids (add K⁺ after voiding), possibly NG tube to decompress
Daily weight, strict I&O, monitor vomiting (amount, character)

Postoperative nursing: pain control (acetaminophen), monitor incision, resume feeds early per protocol (small amounts, advance as tolerated), some vomiting is common for 24–48 h; burp frequently; position upright after feeds; teach incision care.

3. Intussusception

Pathophysiology: a segment of bowel slides into the next segment (often the ileocecal region). Blood supply is squeezed → swelling, mucus, bleeding → ischemia, necrosis, perforation if not treated. Often after a viral illness (enlarged lymphoid tissue as a “lead point”); in older children, look for a lead point (Meckel diverticulum, polyp, lymphoma).

Signs:

Sudden, intermittent, severe crampy pain — the child screams and draws knees to chest, then may be calm or lethargic between episodes
Vomiting (may become bilious)
“Currant jelly” stools (blood and mucus) — a late sign
Sausage-shaped mass in the right upper abdomen; empty right lower quadrant
Lethargy may be the main sign in some infants

Diagnostics: ultrasound (“target” or “donut” sign).

Treatment and nursing:

Air (pneumatic) or hydrostatic (contrast/saline) enema under imaging — reduces most cases
Before: IV fluids, NPO, NG tube if vomiting/distension, monitor for peritonitis/perforation (fever, rigid abdomen, tachycardia, shock)
After reduction: passage of normal brown stool confirms reduction — report it; monitor for recurrence (most within 24–72 h), VS, abdominal exam; advance diet as ordered
Surgery if enema fails or perforation/peritonitis

4. Hirschsprung Disease (Congenital Aganglionic Megacolon)

Pathophysiology: nerve cells (ganglion cells) fail to migrate to the distal bowel, so that segment can’t relax or push stool. Stool backs up above it → the bowel above dilates (megacolon). Associated with Down syndrome and other genetic conditions.

Signs by age:

Newborn: failure to pass meconium within 24–48 h, bilious vomiting, abdominal distension, refusal to feed
Older infant/child: chronic constipation since birth, ribbon-like, foul-smelling stools, distension, failure to thrive; stool impaction without encopresis
: fever, explosive foul diarrhea, marked distension, lethargy → emergency (risk of sepsis and perforation) — can occur before or after surgery

Diagnostics: contrast enema (transition zone), anorectal manometry, rectal suction biopsy = definitive (absence of ganglion cells).

Nursing:

Pre-op: bowel prep/rectal irrigations with isotonic saline only (tap water can cause water intoxication), fluids, nutrition, measure abdominal girth (same spot, every shift), monitor for enterocolitis
No rectal temperatures in suspected Hirschsprung disease and after pull-through
Post-op: pain, NPO/NG until bowel function returns, stoma care if present (pink, moist stoma is normal; dark/dusky = report), perianal skin care (frequent stools/diaper dermatitis), teach signs of enterocolitis

5. Other Pediatric GI Red Flags

Bilious (green) vomiting in an infant = surgical emergency until proven otherwise (e.g., malrotation with volvulus)
GER vs. GERD: spitting up in a happy, growing infant is normal (“happy spitter”); GERD = poor weight gain, irritability, respiratory problems. Safe sleep is still on the back for infants with reflux
Appendicitis: periumbilical pain moving to the RLQ (McBurney point), fever, vomiting, sudden relief of pain = possible rupture; no heat or laxatives/enemas
Necrotizing enterocolitis (NEC) in preterm infants: distension, feeding intolerance, bloody stools

6. Medications

Drug	Use	Notes
Isotonic IV fluids ± KCl	Correct dehydration/electrolytes	K⁺ only after voiding
Analgesics (acetaminophen, opioids as ordered)	Post-op pain	Pain scales by age
Antibiotics (broad-spectrum)	Enterocolitis, perforation	Per order
Stool softeners / bowel regimen	After Hirschsprung surgery as ordered

7. Education

Pyloric stenosis: feeding after surgery, incision care, call for persistent forceful vomiting, fever, or fewer wet diapers
Intussusception: watch for return of crampy pain, vomiting, or bloody stools (recurrence)
Hirschsprung: ostomy care, skin protection, enterocolitis warning signs (fever, swollen belly, explosive or foul diarrhea, lethargy) → go to the ED, hydration, diet

8. Memory Aids

Pyloric stenosis: “Hungry, Projectile, Olive, Alkalotic” — vomiting loses acid → alkalosis
Intussusception: “Telescope, Sausage, Currant jelly, Knees up”
Hirschsprung: “No meconium, No nerves, No rectal temps” — ribbon stools
Green vomit = Go (to surgery)!
Normal brown stool after enema = “Reduced and relieved”

9. NCLEX-Style Practice Questions

1. A 4-week-old first-born male has forceful vomiting after every feeding and wants to eat again immediately. Which lab pattern does the nurse expect?

A. Hyperchloremic metabolic acidosis
B. Hypochloremic, hypokalemic metabolic alkalosis
C. Hyperkalemia with respiratory acidosis
D. Normal electrolytes

Answer: B. Repeated vomiting of gastric acid in pyloric stenosis causes loss of hydrogen and chloride ions (alkalosis) and potassium.

2. A 9-month-old has episodes of screaming with knees pulled to chest, followed by lethargy, and passes a stool of blood and mucus. What is the nurse’s priority?

A. Give a tap-water enema
B. Notify the provider of possible intussusception and prepare for diagnostic imaging
C. Offer oral rehydration and observe at home
D. Give a laxative

Answer: B. These signs suggest intussusception, which can cause bowel ischemia. Prompt ultrasound and air/contrast enema reduction are needed. Laxatives and home observation are unsafe.

3. After an air enema for intussusception, which finding should the nurse report to the provider as an expected sign of successful reduction?

A. Passage of a normal brown stool
B. Return of currant jelly stools
C. Rigid abdomen
D. High fever

Answer: A. A normal brown stool shows the bowel is reduced and working. B suggests recurrence; C and D suggest perforation/peritonitis.

4. A newborn has not passed meconium at 48 hours and has a distended abdomen. Which nursing action is contraindicated if Hirschsprung disease is suspected?

A. Measuring abdominal girth
B. Taking a rectal temperature
C. Monitoring for bilious vomiting
D. Maintaining strict I&O

Answer: B. Rectal temperatures and other rectal manipulation are avoided (perforation risk, and post-op the rectal anastomosis must be protected). The other actions are appropriate.

5. A child who had a pull-through procedure for Hirschsprung disease develops fever, explosive foul diarrhea, and a distended abdomen. What does the nurse suspect?

A. Expected post-op recovery
B. Enterocolitis — report immediately
C. Constipation from opioids
D. Lactose intolerance

Answer: B. Hirschsprung-associated enterocolitis is a life-threatening complication that can occur before or after surgery. Report promptly; expect fluids, antibiotics, and decompression.

References

Anand, S., Kulkarni, K. K., & Sodhani, S. (2026). Hirschsprung disease. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK562142/

Garfield, K., & Sergent, S. R. (2023). Pyloric stenosis. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK555931/

Jain, S., & Haydel, M. J. (2023). Child intussusception. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK431078/

National Council of State Boards of Nursing. (2026). 2026 NCLEX-RN test plan. https://www.nclex.com/test-plans.page