At what age is Hirschsprung disease typically diagnosed in infants?

Age of Presentation of Hirschsprung Disease

Hirschsprung disease is most commonly diagnosed in the neonatal period, with approximately 69% of cases identified within the first 29 days of life, though a significant minority (19-31%) present later in infancy or childhood. 1, 2

Typical Age at Diagnosis

Neonatal Period (Most Common)

• The majority of Hirschsprung disease cases (approximately 69%) are diagnosed during the neonatal period (first 29 days of life), with the average age at presentation being 7-8 days of life 1, 3
• In one series of 26 newborns, the mean age at presentation was 8.3 days 3
• Neonatal presentation typically involves failure to pass meconium, with 42% passing meconium by 24 hours and 58% by 48 hours—significantly delayed compared to normal infants 3

Beyond the Neonatal Period

• Approximately 31% of patients are diagnosed after the neonatal period, with infants (29 days to 12 months) representing a substantial portion 1
• Late diagnosis (defined as ≥1 year of age) occurs in a small but important subset, with median age at diagnosis of 3.4 years in one cohort 4
• Some patients are not diagnosed until toddler years (1-5 years) or even later in childhood (>5 years) 1

Clinical Presentation by Age

Newborn Presentation

• Bilious vomiting occurs in 35% of neonatal cases, with any emesis present in 58% 3
• Abdominal distension is present in 65% at time of presentation 3
• Delayed passage of meconium is the hallmark finding 3
• Enterocolitis can occur even in the newborn period 5

Delayed Presentation (Beyond Neonatal Period)

• Chronic constipation is universal (100%) in late-diagnosed cases 4
• Failure to thrive occurs in 31% of late-diagnosed patients 4
• Enterocolitis occurs in 14% of late-diagnosed cases 4
• Symptoms may be milder, suggesting adaptation to the aganglionic state 6

Special Populations

Preterm Infants

• Hirschsprung disease may be more common in preterm infants than previously recognized, affecting 19% of one large cohort 2
• Preterm infants are significantly more likely to have delayed diagnosis, with 66.7% diagnosed after 30 days of life (median age 2.9 months) compared to 37.1% of term infants 2
• Associated major congenital anomalies are more common in preterm infants (45.8% vs 20.0%), which may contribute to diagnostic delay 2

Associated Conditions

• Down syndrome is present in approximately 15% of neonatal cases, and all affected infants in one series also had cardiac anomalies 3
• Family history of Hirschsprung disease is present in 12% of cases 3
• Overall, 35% of neonatal cases have associated congenital anomalies 3

Diagnostic Considerations

High Index of Suspicion Required

• Recognizing late presentation requires high clinical suspicion, particularly in children with chronic constipation and failure to thrive 4
• Barium enema is diagnostic in 92% of cases when performed 3
• Rectal suction biopsy is definitive, with 100% positivity rate in properly performed biopsies 3
• Primarily rectosigmoid disease is identified in 96% of late-diagnosed cases 4

Clinical Pitfalls

• Do not exclude Hirschsprung disease based on passage of meconium alone—42-58% of affected newborns pass meconium within the first 24-48 hours 3
• Preterm infants with bowel obstruction and associated anomalies warrant particular consideration for Hirschsprung disease 2
• Delayed diagnosis does not necessarily worsen surgical outcomes, but is associated with increased need for postoperative interventions for constipation or incontinence (78% in toddlers vs 56% in neonates) 1