Hirschsprung disease vs Anal atresia and meconium ileus
How to tell Hirschsprung disease and Anal atresia and meconium ileus apart when a board question makes them look alike.
Hirschsprung is aganglionic distal colon; anal atresia is absent anal opening; meconium ileus is CF thick meconium.
Side by side
Hirschsprung disease causes failure of neural crest migration with absent ganglion cells, delayed meconium, explosive stool after rectal exam, RET association, and Down syndrome association.
Anal atresia is imperforate anus; meconium ileus is thick meconium obstruction associated with cystic fibrosis.
RET-linked aganglionosis prevents enteric relaxation in the distal bowel, creating functional obstruction with proximal dilation.
Anal atresia is imperforate anus; meconium ileus is thick meconium obstruction associated with cystic fibrosis.
The repair move
Before naming the answer, force the stem through the separator: Hirschsprung is aganglionic distal colon; anal atresia is absent anal opening; meconium ileus is CF thick meconium.
Try a free question
CoreA 3-day-old neonate has not yet passed meconium and develops bilious vomiting, abdominal distention, and feeding intolerance. On digital rectal exam, there is explosive release of stool and gas. Contrast enema shows a transition zone from a narrow distal rectosigmoid to a dilated proximal colon. Rectal suction biopsy reveals ABSENCE of ganglion cells in the submucosal and myenteric plexuses, with hypertrophic nerve trunks and increased acetylcholinesterase. Family history reveals an uncle with similar problems. Which condition is most likely?
Show answer and explanation
Answer: A. Hirschsprung disease. Hirschsprung disease is congenital aganglionosis from failed neural crest migration to the distal bowel, typically involving the distal rectosigmoid. Failure to pass meconium in first 24-48 hours, explosive stool on rectal exam, transition zone on contrast enema, and absent ganglion cells with hypertrophic nerve trunks and increased acetylcholinesterase on rectal suction biopsy. Associated with RET mutation and Down syndrome.
Why the other choices are tempting
- B. Anal atresia would show no visible anal opening on physical exam.
- C. Meconium ileus is small bowel obstruction from inspissated meconium in cystic fibrosis, not aganglionic colon.
- D. Functional constipation presents later than 3 days and does not have absent ganglion cells.
- E. Hypothyroidism can cause delayed meconium and constipation but does not cause absent ganglion cells.
Flashcards
Tap a card to flip it.
What clue supports Hirschsprung disease?
Choose Hirschsprung disease when the stem gives this pattern: Hirschsprung disease causes delayed meconium, chronic constipation, explosive stool after rectal exam, and aganglionic distal colon from neural crest migration failure.
What clue supports Anal atresia and meconium ileus?
Choose Anal atresia and meconium ileus when the stem gives this contrasting pattern: Anal atresia is imperforate anus; meconium ileus is thick meconium obstruction associated with cystic fibrosis.
Quick answers
What is the fastest way to tell Hirschsprung disease from Anal atresia and meconium ileus?
Hirschsprung is aganglionic distal colon; anal atresia is absent anal opening; meconium ileus is CF thick meconium.
What is the key clue for Hirschsprung disease?
Hirschsprung disease causes failure of neural crest migration with absent ganglion cells, delayed meconium, explosive stool after rectal exam, RET association, and Down syndrome association.
What is the key clue for Anal atresia and meconium ileus?
Anal atresia is imperforate anus; meconium ileus is thick meconium obstruction associated with cystic fibrosis.