Increased head circumferenceMacrocephaly
Increased head circumference is when the measured distance around the widest part of the skull is larger than expected for the child's age and background.
A newborn's head is usually about 2 centimeters larger than the chest size. Between 6 months and 2 years, both measurements are about equal. After 2 years, the chest size becomes larger than the head.
A series of measurements over time that show an increased rate of head growth often can provide more valuable information than a single measurement that is larger than expected.
Increased pressure in the head (increased intracranial pressure) often occurs with increased head circumference. Symptoms of this condition include:
See also: Bulging fontanelles
- Benign familial macrocephaly (family tendency toward large head size)
- Canavan disease
- Hurler syndrome
- Hydrocephalus (congenital, post-traumatic, or obstructive)
- Intracranial bleeding
- Morquio syndrome
When to Contact a Medical Professional
The health care provider usually finds macrocephaly during a routine well-baby exam.
What to Expect at Your Office Visit
The health care provider will take a medical history and will perform a physical examination.
Medical history questions may include:
- Time pattern
- When did you first notice that the baby's head seemed large?
- Does the baby's head size seem to be increasing faster compared to the growth of the body?
- Does the head seem larger all over?
- Is the head growing more in a front-to-back pattern or in a side-to-side pattern?
- What other symptoms are present (especially changes in brain or nervous system functions)?
The distance is measured in centimeters or inches and compared with:
- Past measurments of a child's head circumference
- Normal ranges for a child's sex and age (weeks, months) -- based on normal growth rates of infants' and children's heads
A careful physical exam will be done. Other milestones for growth and development will be checked.
In some cases, a single measurement is enough to confirm that there is a size increase that needs to be tested further. More often, repeated measurements of the head circumference over a period of time are needed to confirm that the head circumference is increased and the problem is getting worse.
Diagnostic tests vary depending on the cause, but often include:
Review Date: 5/1/2011
Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.