Signs, Symptoms & Clinical Features
Increased head circumference
An increased head circumference, especially when growing rapidly, is a key early sign of hydrocephalus in infants.
In short: Increased head circumference
- It is the measurement around the head increasing over time.
- Rapid crossing of growth percentiles is a warning sign.
- It is a key way hydrocephalus is detected in babies.
- It is plotted on growth charts at routine visits.
What it is
Increased head circumference refers to a rising measurement of the distance around the largest part of an infant's head. When it increases rapidly — crossing upward across growth chart percentiles — it is an important early sign of hydrocephalus.
Understanding Increased head circumference
Because an infant's skull can expand, accumulating CSF often shows up first as accelerating head growth rather than as raised-pressure symptoms. Measuring head circumference at routine visits and plotting it on growth charts allows the team to detect a head that is growing too fast — a pattern that prompts evaluation for hydrocephalus, including imaging. A single large measurement is less concerning than a rapid upward trend across percentiles. This simple measurement is one of the most valuable tools for detecting hydrocephalus in babies.
Why it matters
Understanding increased head circumference helps families see why head measurements are taken and tracked at every infant visit, and why rapid head growth is a warning sign that prompts evaluation.
Common questions
Why is head circumference tracked in babies?
Rapid increases can signal hydrocephalus.
What pattern is concerning?
Crossing upward across growth percentiles quickly.
How is it measured?
With a tape around the largest part of the head, plotted on growth charts.
Bottom line
An increasing head circumference, especially rapid growth across percentiles, is a key early sign of hydrocephalus in infants.
Browse all 265 Hydrocephalus definitions
Read the Hydrocephalus patient guides
Not sure which page you need? Put words to it with the symptom navigator