Increased head circumference
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:
- Head CT scan
- MRI of the head
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.
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