A 7-month-old boy is brought to the office due to streaks of blood in his stools. The infant was exclusively breastfed until a month ago, when rice cereal and cow's milk–based formula were introduced into his diet. Previously, stools were soft and yellow and occurred at least once a day. For the past 3 weeks, however, stools have become hard and pellet-like, occurring every 2-3 days. In the past week, the patient's mother noticed thin streaks of bright red blood on the outside of the stools. The patient has had no change in appetite, vomiting, or fever. Height and weight have been tracking along the 25th percentile since birth. Vital signs are normal. On examination, the patient is in no distress. The abdomen is mildly distended, and there is no pain on palpation. There is firmness on palpation in the left lower quadrant and a small anal fissure at the 6 o'clock position. The remainder of the examination is unremarkable. Which of the following is the most appropriate management of this patient?
Infant constipation | ||
Functional | Pathologic causes | |
Risk factors |
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Clinical features |
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Management |
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This infant with recent onset of infrequent, pellet-like stools after introduction of solid foods likely has functional constipation. Functional constipation is the most common cause of constipation in children and has no serious organic cause. In contrast, pathologic constipation should be suspected if alarm signs are present, such as delayed passage of meconium in the neonatal period, poor growth, or severe abdominal distension.
Functional constipation often presents around age 6 months because the major risk factor in this age group is dietary change (eg, solid foods with relatively low fiber and decreased fluid content). Growth is normal, and physical examination is often unremarkable. However, mild abdominal distension and left lower quadrant firmness or palpable stool may be present due to stool retention. In addition, large-caliber stools can cause an anal fissure and bright red blood on the outside of stools, as seen in this infant.
Diagnosis of functional constipation in infants is usually clinical, and initial management is dietary, including the addition of apple, prune, or pear juice/puree. These nondigestible, osmotically active carbohydrates (eg, sorbitol) pull water into the gastrointestinal tract, thereby softening stool. Like treatment of functional constipation in older children, the addition of laxatives (eg, polyethylene glycol) can be considered in infants who have refractory constipation with dietary changes.
(Choices B and C) A barium enema is used to evaluate for Hirschsprung disease, which usually presents in the neonatal period with delayed meconium passage, but can cause chronic, refractory constipation in infancy. An abdominal radiograph may also show absent rectal air and dilated proximal bowel loops. In contrast to this patient, failure to thrive and severe abdominal distension would be expected. In addition, imaging is not indicated in the evaluation of functional constipation but can be considered in cases that are refractory to initial management.
(Choices D and E) Hydrolyzed formulas, which contain preprocessed, less allergenic proteins, treat food protein-induced allergic proctocolitis (eg, cow's milk protein allergy); soy formula can also be considered. This disorder typically presents in infants age <6 months with loose stools that have mucus and blood mixed in. In contrast, this patient has blood on the outside of hard stools, findings characteristic of an anal fissure due to constipation.
Educational objective:
Functional constipation in infants usually presents after introduction of solid foods (eg, lower fiber, decreased fluids) and without alarm signs (eg, poor growth, severe abdominal distension). Initial treatment is with nondigestible osmotically active carbohydrates (eg, fruit juice/puree).