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.

Considerations

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.

Measurements over time that show an increased rate of head growth often provide more valuable information than a single measurement that is larger than expected.

Increased pressure inside the head (increased intracranial pressure) often occurs with increased head circumference. Symptoms of this condition include:

• Eyes moving downward
• Irritability
• Vomiting

Causes of Increased head circumference

• 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 Health 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?
• Location
  • 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?
• Other
  • What other symptoms are present (especially changes in brain or nervous system functions)?

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 are needed to confirm that the head circumference is increased and the problem is getting worse.

Diagnostic tests that may be ordered include:

• Head CT scan
• MRI of the head

References

Cohen MM Jr. Overgrowth syndromes. In: Gilbert-Barness E, Kapur RP, Oligny LL, et al., eds. Potter's Pathology of the Fetus, Infant and Child. Philadelphia, PA: Elsevier Mosby; 2007:chap 41.

Kinsman SL, Johnston MV. Congenital anomalies of the central nervous system. In: Kliegman RM, Stanton BF, St. Geme JW III, et al., eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 585.