Clinical, Radiological, and Demographic Details of Benign External Hydrocephalus: A Population-Based Study

Area of Science:

• Pediatric Neurology
• Neuroradiology
• Infant Health

Background:

• Benign external hydrocephalus (BEH) affects approximately 0.4 per 1000 live births.
• Characterized by rapid head circumference increase and specific neuroimaging findings in infants.
• Previous studies often involved small, selected patient groups, limiting generalizability.

Purpose of the Study:

• To report on the incidence and characteristics of benign external hydrocephalus (BEH).
• To follow up on a recently published study on BEH incidence.
• To analyze a large, population-based cohort for a comprehensive understanding of BEH.

Main Methods:

• Retrospective, population-based study across two Norwegian health regions (1994-2003).
• Inclusion criteria: infants with increasing head circumference and typical radiological findings of enlarged subarachnoid spaces.
• Data collected: head circumference, neuroimaging, delivery methods, and demographics from medical records.

Main Results:

• 176 infants diagnosed with BEH; 86.4% were male.
• Abnormal head circumference typically developed by 3.4 months (range: birth to 7 months).
• Most infants (80%) had dilated lateral ventricles alongside enlarged subarachnoid spaces; neuroimaging normalized by 12 months for many.

Conclusions:

• Infants with BEH usually have normal head circumference at birth, with rapid enlargement before six months.
• The age and gender distribution of BEH mirrors that of infant subdural hemorrhage.
• Findings suggest a distinct pattern of rapid head growth in BEH, distinct from other causes of macrocephaly.