A 15-month-old boy is brought to the clinic for evaluation of worsening constipation. The patient has had chronic constipation since early infancy. His parents had tried giving him prune juice and increasing his dietary fiber with no improvement. The symptoms worsened after he transitioned from breast milk to cow's milk at age 1. The patient seems to strain even more now during bowel movements, and the stools are thin. While changing his diaper this morning following a bowel movement, his mother noticed a few streaks of bright red blood. The patient was born at term and has otherwise been healthy. Height and weight are at the 10th percentile. Temperature is 37.5 C (99.5 F), pulse is 130/min, and respirations are 30/min. The patient is awake and alert. Cardiopulmonary examination is unremarkable. The abdomen is protuberant and diffusely mildly tender to palpation. Bowel sounds are present, and there is no rebound or guarding. The external anus appears unremarkable. Rectal examination results in expulsion of stool and gas. Stool occult blood testing is positive. Which of the following is the best next step in management of this patient?

Question

A 15-month-old boy is brought to the clinic for evaluation of worsening constipation.  The patient has had chronic constipation since early infancy.  His parents had tried giving him prune juice and increasing his dietary fiber with no improvement.  The symptoms worsened after he transitioned from breast milk to cow's milk at age 1.  The patient seems to strain even more now during bowel movements, and the stools are thin.  While changing his diaper this morning following a bowel movement, his mother noticed a few streaks of bright red blood.  The patient was born at term and has otherwise been healthy.  Height and weight are at the 10th percentile.  Temperature is 37.5 C (99.5 F), pulse is 130/min, and respirations are 30/min.  The patient is awake and alert.  Cardiopulmonary examination is unremarkable.  The abdomen is protuberant and diffusely mildly tender to palpation.  Bowel sounds are present, and there is no rebound or guarding.  The external anus appears unremarkable.  Rectal examination results in expulsion of stool and gas.  Stool occult blood testing is positive.  Which of the following is the best next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d67f_0c31_bc81_ddc286514310_MD0003_00 This child has chronic constipation concerning for Hirschsprung disease, a condition in which failed fetal neural crest cell migration results in an aganglionic colonic segment. Patients with a long segment of affected colon classically present in the newborn period with delayed passage of meconium. However, in patients with a short aganglionic colonic segment, symptoms often develop in infancy or early childhood and include chronic, refractory constipation and poor growth or failure to thrive. Classic rectal examination in patients with Hirschsprung disease reveals an expulsion of stool or gas ("squirt sign") due to temporary relief of the distal obstruction. Additional findings include abdominal distension and tenderness and thin caliber stools due to failure of the distal colon to relax. Blood with bowel movements may be seen with hemorrhoids caused by straining or anal fissures from hard stools. As seen in this case, patients do not typically respond to standard constipation treatment (eg, increased dietary fiber). Evaluation for Hirschsprung disease includes a contrast enema, which shows a transition zone between a distal, narrowed aganglionic segment and a proximally dilated colon. Rectal suction biopsy confirms the diagnosis. contrast enema (Choices A and E) Increased solid food intake and the transition to cow's milk may trigger constipation in some children and is typically due to suboptimal dietary fiber. Limiting the daily intake of cow's milk, switching to a soy product, or adding polyethylene glycol could improve symptoms. However, this patient's chronic constipation since early infancy and positive squirt sign make a recent dietary change an unlikely cause of symptoms. (Choice C) Meckel diverticulum typically causes painless rectal bleeding or can act as a lead point for intussusception, causing acute abdominal pain. This patient's chronic constipation, thin stools, and abnormal rectal examination would not be seen in this condition. (Choice D) Colonoscopy may be indicated in a child with rectal bleeding, abdominal pain, and failure to thrive to evaluate for inflammatory bowel disease, a rare diagnosis in toddlers. Diarrhea, not constipation, would be expected, and expulsion of gas and stool would not be seen with rectal examination. Educational objective: Hirschsprung disease is characterized by an aganglionic colonic segment. A short affected segment can cause chronic refractory constipation and poor growth in young children, and expulsion of gas and stool on rectal examination is classic. Evaluation includes a contrast enema, which reveals a transition zone between a distal, narrowed aganglionic segment and a proximally dilated colon. References: Pediatric intestinal motility disorders. (http://www.ncbi.nlm.nih.gov/pubmed/26361414) Hirschsprung disease beyond infancy. (http://www.ncbi.nlm.nih.gov/pubmed/29487487)

A 15-Month-Old Boy Is Brought to the Clinic for Evaluation