Signs, Symptoms & Clinical Features
Macrocephaly
Macrocephaly is a larger-than-expected head size, which in infants can be a sign of hydrocephalus.
In short: Macrocephaly
- It means a head circumference larger than expected for age.
- In infants, it can signal hydrocephalus.
- It is tracked on growth charts over time.
- Not every large head indicates a problem.
What it is
Macrocephaly is a head circumference larger than expected for a child's age and sex. In infants, whose skull can still expand, it can be an important sign of hydrocephalus.
Understanding Macrocephaly
Because a baby's skull bones are not yet fused, accumulating CSF in hydrocephalus can cause the head to enlarge rather than pressure rising as quickly — so a rapidly increasing or disproportionately large head is a key sign to watch for. However, not every large head means hydrocephalus: some macrocephaly reflects family traits (benign familial macrocephaly) or benign external hydrocephalus. The team interprets head size by plotting measurements on growth charts and watching the trend over time, combined with other signs and, when needed, imaging. The pattern of growth matters more than a single measurement.
Why it matters
Understanding macrocephaly helps families see why head size is measured at every visit in infancy, and why a rapidly growing or disproportionately large head is a signal to evaluate for hydrocephalus.
Common questions
What is macrocephaly?
A larger-than-expected head size.
Can it signal hydrocephalus?
In infants, it can.
Does a large head always mean a problem?
No — the trend over time matters, and some reflect family traits.
Bottom line
Macrocephaly is a larger-than-expected head size that, in infants, can signal hydrocephalus, interpreted by the trend over time.
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