A 5-month-old girl is admitted to the hospital with chronic constipation, foul-smelling and ribbon-like stool, and abdominal distention. Upon assessment, the nurse suspects Hirschsprung's disease. The diagnosis is confirmed if a barium enema reveals

megacolon

Explanation

• Hirschsprung's disease is an absence of innervation to the smooth muscle of a section of the bowel. In most instances, this is the lower portion of the sigmoid colon just above the anus. The absence of nerves means there is no peristalsis in this area to push fecal material through this segment of intestine. This results in chronic constipation or ribbon-like stools. The portion of the bowel proximal to the obstruction dilates, distending the abdomen.

• A barium enema is generally ordered to confirm the diagnosis. On x-ray film, the barium will outline a narrow, nerveless distal colon with a proximal dilation referred to as megacolon.

Incorrect options:

• Intussusception is an invagination or telescoping of one portion of the intestine into an adjacent portion, causing obstruction.

• In pyloric stenosis, ultrasonography and an upper GI study may reveal delayed gastric emptying, an elongated band thin pylorus, or a pyloric mass.

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