Hydrocephalus

An imbalance between CSF production and absorption, usually from an obstruction to circulation — needs early referral for consideration of VP shunting. See also 6-week check (fontanelle assessment).

Consider hydrocephalus if head circumference is increasing out of proportion to the other growth parameters. A head circumference well above the 97th centile warrants specialist referral to assess for serious underlying causes.

Presentation by rate of accumulation

• Slow accumulation — bulging fontanelle; widening of the coronal/ sagittal/lambdoid sutures. Neurological abnormalities in mild hydrocephalus tend to relate to the underlying disorder rather than the hydrocephalus itself. In older children: gait change (wide-based or clumsy), tremor, incoordination, abnormal articulation.
• Rapid accumulation — the head doesn’t have time to accommodate. The child appears unwell: short, high-pitched crying, decerebrate posturing, irritability, vomiting.

Investigations

Ultrasound while the anterior fontanelle remains open; CT for more detailed assessment in older children.

Referral

Refer to paediatrics with urgency guided by the speed of suspected accumulation and any associated neurological findings. A routine referral is reasonable for an infant with an enlarged head and no other abnormalities.