A 2-day-old male infant has not passed any meconium and is now developing signs of obstruction. Examination of the colon would reveal which of the following abnormalities?
(A) absence of parasympathetic ganglion cells in the submucosal and myenteric plexus
(B) absence of the nerve fibers that innervate the wall
(C) atrophy of the mucosal lining of the wall
(D) hypertrophy of the muscle coat of the wall
(E) presence of multiple small polyps along the mucosal surface
Answer:
A:
Hirschsprung disease is caused by the congenital absence of parasympathetic ganglion cells in the submucosal and myenteric plexus. This presents clinically soon after birth as an inability to pass stool and abdominal distention. The diagnosis is usually confirmed by a full-thickness colon biopsy showing disorganized, nonmyelinated nerve fibers replacing the missing ganglion cells. In Hirschsprung disease, the ganglion cells, not the nerve fibers (choice B), are missing. Muscular hypertrophy (choice D) and atrophy (choice C) are not specific diagnostic findings with Hirschsprung disease. Mucosal polyp development (choice E)is not associated with Hirschsprung disease.
(A) absence of parasympathetic ganglion cells in the submucosal and myenteric plexus
(B) absence of the nerve fibers that innervate the wall
(C) atrophy of the mucosal lining of the wall
(D) hypertrophy of the muscle coat of the wall
(E) presence of multiple small polyps along the mucosal surface
Answer:
A:
Hirschsprung disease is caused by the congenital absence of parasympathetic ganglion cells in the submucosal and myenteric plexus. This presents clinically soon after birth as an inability to pass stool and abdominal distention. The diagnosis is usually confirmed by a full-thickness colon biopsy showing disorganized, nonmyelinated nerve fibers replacing the missing ganglion cells. In Hirschsprung disease, the ganglion cells, not the nerve fibers (choice B), are missing. Muscular hypertrophy (choice D) and atrophy (choice C) are not specific diagnostic findings with Hirschsprung disease. Mucosal polyp development (choice E)is not associated with Hirschsprung disease.
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