What is Macrocephaly?

Mary McMahon
Mary McMahon

Macrocephaly is a condition in which a child's head is larger than normal. If the circumference of the head is more than two standard deviations above the average for children of a similar race and age, the child will be diagnosed with macrocephaly. There are a number of causes for this condition, which is not curable, because it involves skeletal abnormalities. Once the skull has achieved an unusually large size, it cannot be shrunk back down.


Also known as macrocephalia or megalocephaly, macrocephaly is commonly caused by an enlarged brain or by a buildup of fluid in the skull. Both conditions force the skull to grow larger to accommodate an increased volume. In the case of an enlarged brain, no treatment can be recommended, but fluid in the brain can be drained off with a shunt. Since the skull of a child is still growing, draining fluid early may slow the growth, allowing the child's head to achieve a normal size, or it may reduce the severity of the macrocephaly.

Another cause for macrocephaly is a chronic subdural hematoma, in which blood on the brain causes the skull to grow to accommodate extra fluid. This condition can be very serious. All of the above causes of macrocephaly can lead to developmental delays, including movement disorders, intellectual delays, and seizures. For this reason, when an unusually large head is identified, care is taken to diagnose it properly to ensure that everything possible is being done for the patient.

Macrocephaly can also be benign in nature. Benign or familial macrocephaly has no associated problems. Some people, in other words, just have big heads. This condition is also linked with some genetic conditions which can cause a variety of medical problems which include abnormalities in skull development. These conditions may be diagnosed during the pregnancy or after the birth with observation, tests, or medical imaging studies which can identify abnormalities.

In the case of benign macrocephaly, parents don't need to do anything special to meet the needs of their child. Macrocephaly which is related to another medical problem may require more monitoring and treatment, including occupational therapy to help children with movement disorders and treatment of the complications associated with many genetic disorders which lead to abnormal head size. It is important for parents of children with genetic abnormalities to be outspoken advocates for their children; every condition manifests slightly differently, and proactive care can make a big difference in quality of life, future health, and independence.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


I just found out my 16 month old has this and I'm worried because she also has Hypotonia, and then they think she has Celiac Disease and a systolic murmur. Is there any way that all these are connected? Her head measured bigger then it should have. The doctor even measured my head and mine was normal, so now all this testing has to be done and it could turn out to be nothing or it could be major. Am I overreacting?


I had a friend when I was younger who had a child with macrocephaly as a result of Robinow syndrome. It is a very rare genetic disorder. She did not know it was in her family.

It was hard for her not to blame herself, but the disease was not something that was made public information to her or her parents. She didn’t know to look for it.

Fortunately, her child suffered from the dominant form, rather than the recessive. The dominant form tends to have more moderate symptoms. Along with the macrocephaly, most of the symptoms were like those of dwarfism.


There are a surprising number of causes of macrocephaly in children. I have seen cases where an enlarged skull was caused by tumors in the central nervous system, fluid in the brain, disorders of the brain myelin, and disorders with bone growth.

The treatment, of course, varies with the disorder that is causing the macrocephaly. It is unfortunate that once the skull has become enlarged, there isn’t much to be done. I think early diagnosis and treatment is the best way to get results.

With some of these ailments presenting with a variety of other symptoms, I would not hesitate to speak to your family practitioner or pediatrician any time you suspect something might be wrong. Remember, doctors and nurses (like me), and other medical staff are there to help you.


My friend’s youngest son just turned one year old. Their pediatrician believes he may have macrocephaly. My friend refuses to let her son be tested. She says since his soft spots on his head are pretty much closed, an ultrasound won’t be effective for diagnostic purposes.

According to her, the alternative is to sedate her one year old son and have a scan done. She refused to have her son sedated. She says both she and her husband had large heads as children. Her son does have a large head. I hope it is just familial macrocephaly.

The presentation of macrocephalic symptoms would be enough to have me concerned. I would have my child undergo the tests. I can’t imagine having my child suffer from something like this when the diagnostic testing isn’t even invasive.

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