Why can hydrocephalus cause a baby's head to enlarge?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Infographic showing estimated lives saved by childhood vaccinations worldwide from 1974 to 2024, with syringe-shaped bars for each disease. Measles tops the list at 93.71 million lives saved, followed by tetanus, whooping cough, and others, for a total of 153.84 million lives saved. — childhood disease and disorder Vaccines and the estimates of lives saved over the period 1974–2024.

Hydrocephalus causes a baby's head to enlarge because of the accumulation of cerebrospinal fluid within the brain's ventricles.1

In infants, the individual bones of the skull have not yet fused together. These junctions, known as fontanels, allow for flexibility in the infant's head. When fluid builds up, the resulting internal pressure forces these unfused bones to bulge outward at their juncture points, leading to a visible and progressive enlargement of the head. If left untreated, this pressure can compress the brain, potentially resulting in convulsions and intellectual disability. Medical intervention typically involves the surgical insertion of a shunt to drain the excess fluid and relieve intracranial pressure.123