Macrocephaly is the technical term for a large head.
Macrocephaly can be caused by genetic disorders or other disorders or can be normal and run in families.
Diagnosis is made before birth through routine ultrasound tests or after birth by measuring the head circumference and sometimes by doing imaging tests.
Doctors usually do an imaging test to look for brain abnormalities and genetic testing to look for a cause.
Treatment for abnormal macrocephaly usually includes surgery.
Infants with macrocephaly have a head circumference that is considerably larger than others of the same age.
Macrocephaly can be classified as:
Disproportionate: The head is larger than appropriate for the child's overall size.
Proportionate: The head appears appropriately sized for the body (in other words, the child has a large body and a large head).
Many people with large heads or large skulls are healthy.
The most common cause of macrocephaly is familial macrocephaly, in which a larger head size runs in the child's family because of features of the skull and brain growth.
Abnormal macrocephaly may be caused by an enlarged brain (megalencephaly), fluid on the brain (hydrocephalus), overgrowth of the bones of the skull (cranial hyperostosis), or other conditions. These conditions may be the result of genetic disorders or of disorders acquired before or after birth.
Children may also have complications, for example, lazy eye (also called amblyopia), misaligned teeth, and/or speech difficulties related to effects on the mouth and jaw.
Diagnosis of Macrocephaly
Before birth, ultrasound
After birth, physical examination, including measurement of head circumference and sometimes imaging tests
Genetic testing
Before birth, the diagnosis sometimes is made with a routine prenatal ultrasound test done late in the second trimester or early in the third trimester.
After birth, doctors measure a baby's head circumference (the measurement of the head around its largest area) during routine physical examinations. They diagnose macrocephaly when the head circumference is significantly larger than the normal range for babies of the same sex, age, and ethnic group in the region where the baby lives. When making the diagnosis, doctors also take into account the head circumference of the baby's parents and grandparents because a slightly larger head size may run in the family.
If macrocephaly is present at birth, doctors usually do ultrasounds of the newborn's head to look for hydrocephalus, large cysts, or other mass lesions, and they sometimes do CT scans of the newborn's head to evaluate the skull bones. However, a specialist helps determine when an MRI scan of the brain needs to be done to look for other brain abnormalities. Sometimes the doctor may request blood tests to help determine the cause.
A baby who has this birth defect may be evaluated by a geneticist. A geneticist is a doctor who specializes in genetics (the science of genes and how certain qualities or traits are passed from parents to offspring). Genetic testing of a sample of the baby's blood may be done to look for chromosome and gene abnormalities. This testing can help doctors determine whether a specific genetic disorder is the cause and rule out other causes.
Treatment of Macrocephaly
Sometimes surgery
Intervention for physical and intellectual problems
In children who have familial macrocephaly, treatment is not necessary.
Most children who have abnormal macrocephaly are treated surgically if the disorder is getting worse or if they also have hydrocephalus (see, for example, Treatment of Hydrocephalus) or a mass lesion. Surgery is done to restore function and improve appearance.
Except for children who have familial macrocephaly, those who have other types of macrocephaly may have developmental delays. Developmental services, known as early intervention, often help children with macrocephaly maximize their physical and intellectual abilities. Regular check-ups and follow-ups by a care team are very important.
Children who have complications such as amblyopia, misaligned teeth, and speech difficulties should be treated by appropriate specialists.
