Drugs History: Recent use of drugs known to cause constipation Narcotics Examination: Features suggest functional constipation Psychotropics Laboratory: No specific tests available symptoms from birth. Functional constipation is overwhelmingly the most common diagnosis in older patients. Constipation in older children often begins after starting school, when free and private access to toilets may be restricted. Use of some drugs, especially opiates and some psychotropic medications, also is associated with constipation.
For a few specific causes of constipation, directed diagnostictesting can make the diagnosis. A narrowed, aganglionic distalbowel and dilated proximal bowel on barium enema suggestsHirschsprung disease. Rectal suction biopsy confirms the absenceof ganglion cells in the rectal submucosal plexus, with hypertrophy of nerve fibers. Lack of internal anal sphincter relaxation canbe shown by anorectal manometry in Hirschsprung’s disease.Hypothyroidism is diagnosed by examination and by thyroidfunction testing. Anorectal malformations are easily detected byrectal examination. Cystic fibrosis (meconium ileus) is diagnosedby sweat chloride determination or CFTR gene mutation analysis (see Chapter 137). Most children with constipation have functional constipation and do not have any laboratory abnormality. Examination reveals normal or reduced anal sphincter tone(owing to stretching by passage of large stools). Fecal impaction isusually present, but a large-caliber, empty rectum may be found ifa stool has just been passed.
Evaluation and Treatment of Functional Constipation
In most cases of constipation, the history is consistent with functional constipation—absence of neonatal constipation, active fecal retention, and infrequent, large stools with soiling. In these patients, no testing other than a good physical examination is necessary. Young children with painful defecation must have a prolonged course of stool softener therapy to alleviate fear of defecation. The child should be asked to sit on the toilet for a few minutes on awakening in the morning and immediately after meals, when the colon is most active and it is easiest to pass a stool. Use of a positive reinforcement system for taking medication and sitting on the toilet is helpful for younger children. The stool softener chosen should be non–habit forming, safe, and palatable. Polyethylene glycol and milk of magnesia are the most commonly used agents.
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GI tract bleeding can be an emergency when large-volume bleeding is present, but even the presence of small amounts of blood in stool or emesis is sufficient to cause concern. Evaluation of bleeding should include confirmation that blood truly is present, estimation of the amount of bleeding, stabilization of the patient’s intravascular blood volume, localization of the source of bleeding, and appropriate treatment of the underlying cause. When bleeding is massive, it is crucial that the
Ingested maternal blood* Hematemesis or rectal, large Apt test indicates adult hemoglobin is present, cracked maternal nipples, amount
Peptic disease Hematemesis, amount varies Blood found in stomach on lavage
Coagulopathy Hematemesis or rectal, bruising, other sites History of home birth (no vitamin K)
Allergic colitis* Streaks of bloody mucus in stool Eosinophils in feces and in rectal mucosa
Necrotizing enterocolitis Rectal Sick infant with tender and distended abdomen
Volvulus Hematemesis, hematochezia Acute tender distended abdomen
Peptic disease Usually hematemesis, rectal possible Epigastric pain, coffee-ground emesis
Esophageal varices Hematemesis History or evidence of liver disease
Intussusception* Rectal bleeding Crampy pain, distention, mass
Meckel diverticulum* Rectal Massive, bright red bleeding; no pain
Bacterial enteritis* Rectal Bloody diarrhea, fever