Neonatal-onset constipation with growth delay

Specialty: Pediatrics.

• Organic constipation of infants
• suspected aganglionic megacolon

Why it occurs

• Short or long segment Hirschsprung disease (absence of myenteric and submucosal plexuses in the distal colon that prevents reflex relaxation of the internal anal sphincter and normal peristalsis, causing persistent constipation from the first weeks of life and secondary malnutrition)
• Congenital hypothyroidism with late diagnosis (thyroid hormone deficiency that slows down global cellular metabolism and intestinal transit, also limiting linear and weight growth)
• Cystic fibrosis (exocrine pancreatic insufficiency associated with dehydrated intestinal mucus that causes subacute obstruction and severe absorptive insufficiency)
• Congenital anal stenosis or mild obstructive anorectal malformation (anatomical narrowness that makes stool evacuation difficult, requiring intense efforts and causing colonic dilation)
• Renal tubular acidosis or other metabolic errors (chronic ionic disorders that cause constipation secondary to dehydration and marked weight loss)

Initial workup

Simple AP and lateral abdominal radiography (to assess gas distribution and rule out megacolon). Opaque enema with water-soluble contrast performed without prior preparation (to identify the characteristic caliber-narrow transition zone between the dilated healthy colon and the narrow aganglionic colon). Rectal aspiration biopsy (gold standard for the diagnosis of Hirschsprung by demonstrating the absence of ganglion cells and hypertrophy of cholinergic fibers). Thyroid function tests (TSH, free T4). Sweat test (to rule out cystic fibrosis). Capillary gasometry and ionogram (rule out renal tubular acidosis and hypokalemia).

Standard management

• The definitive treatment of Hirschsprung's disease and anorectal malformations is surgical — resection of the aganglionic segment and colorectal descent). Prior to surgery, repeated rectal washings with warm physiological saline are performed using a soft probe to decompress the colon. Levothyroxine sodium (specific treatment of congenital hypothyroidism; dose of 10 to 15 mcg/kg/day orally
• Pancreatic enzymes — specific oral supplementation with the intakes in case of confirmed cystic fibrosis
• Avoid the use of stimulant laxatives or sennosides in young infants.