Macrocephaly In Babies: Possible Causes, Diagnosis & Treatment

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Macrocephaly in babies is characterized by a disproportionate and abnormally large swelling of the skull. It is also known as large head syndrome or big head. Most often, it is a sign of an underlying problem.

Parents may be worried about the unusual appearance of macrocephaly. However, macrocephaly can be treated depending on the cause of the condition. The treatment can range from medications that help control the swelling to surgery.

Read this article to understand more about macrocephaly in babies, including the possible causes, diagnostic measures, and treatment options.

What Is Macrocephaly?

Macrocephaly in babies

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Macrocephaly, also called big head or large head syndrome, is a condition that causes an abnormal increase in the head circumference of the baby. Not all babies have the same head circumference. Therefore, physicians divide head circumferences into different percentiles (1).

If the circumference falls within the healthy range for their age and gender, then it is considered normal. Medical experts define macrocephaly as a condition where the baby’s head circumference (in centimeters or inches) is greater than the 98th percentile (2). There could be several reasons for macrocephaly.

What Causes Macrocephaly In Babies?

Here are a few reasons why an infant could have a large head or develop one (3):

  1. Hydrocephalus is a condition that causes excessive cerebrospinal fluid to accumulate within the ventricles (spaces) of the brain. It is one of the most common brain disorders among infants (4). The excess fluid swells the skull. Hydrocephalus itself can occur due to several diseases ranging from congenital hydrocephalus to an injury or an infection.
  1. Nervous system infections can cause the brain and skull to enlarge in size. Examples include meningitis, an infection of the membrane covering the brain, and encephalitis, a severe inflammation of the brain tissue. Infections can develop due to pathogens such as bacteria and viruses.
  1. Rickets is caused due to the deficiency of vitamin D in the body. Rickets cause abnormalities of the skeletal system including bones of the skull. The skull can expand in size causing a big head (5).
  1. Brain disorders: Problems in the brain, such as a tumor, can cause a large head in babies. Some congenital deformities of the brain that can cause macrocephaly are hydranencephaly (lack of cerebrum) and megalencephaly (abnormal increase in brain matter).
Quick fact
Anatomic megalencephaly (without any metabolic disease process) is most often familial and benign (10).
Problems in the brain can cause thid condition in babies.

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  1. Genetic disorders: Defective genes can also cause macrocephaly. One of the most notable ones is the Sotos syndrome. It is a genetic disorder that affects the skeleton leading to many problems including the development of an unusually large head (6). Infants with autism may also display macrocephaly on attaining toddlerhood (7).
Quick fact
Fragile X syndrome, Gorlin syndrome, and Cowden syndrome may also cause macrocephaly (10).

There could be situations where macrocephaly is a normal occurrence. In such cases, the baby will not display any health-related symptoms and will grow normally. There is nothing to worry in such situations. Nevertheless, if you suspect the infant’s skull to be going out of shape and disproportionate to the body, then do not hesitate to see the doctor.

How Is Macrocephaly Diagnosed In Babies?

Physicians measure the height, weight, and head circumference of the infant and are likely to detect macrocephaly during a routine checkup in the first year of the baby’s life. Doctors will use the following tools to check for the underlying condition that led to a large head in babies:

  1. Physical examination: The doctor checks for the external appearance and feels the fontanelle (soft spot) on the baby’s skull. Some brain disorders like hydranencephaly can be diagnosed by illuminating the skull with a bright light. The doctor will also check for signs of internal bleeding that could suggest brain trauma.
Physical examination, Macrocephaly in babies

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  1. Observing other symptoms: Doctors check if the baby is irritable, has poor suckling reflex, displays extreme lethargy, and has missed any of the developmental milestones. These symptoms could indicate a disability-causing genetic disorder.
  1. Ultrasound: An ultrasound can give a quick analysis of what lies beneath the skull. It can help doctors decide the further course of testing.
  1. CT scan: Computerized tomography scan, or CT scan, takes multiple X-rays of the skull to create a three-dimensional image. It helps to check the outline of the skull and the point of deformity.
  1. MRI: Magnetic resonance imaging (MRI) uses a magnetic field to generate a highly accurate and elaborate image of the entire skull. While an MRI gives a detailed picture of macrocephaly, it requires the person to stay still.

So the doctors may use a bit of sedation to keep the infant still within the MRI scanner. Several hospitals now perform a “Quick MRI” without sedation, which is advisable for pediatric patients although this form of MRI has limited image rendering capabilities (8).

  1. Blood test and fluid collection: A blood test may help assess the presence of genetic problems. The doctor may even collect a sample of the cerebrospinal fluid from the base of the spinal cord, using a procedure called spinal tap. The fluid may also be obtained from the top layers of the brain depending on the condition of the skull.
Blood test may help assess the presence of genetic problems

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Once your doctor has the diagnosis, they will recommend the best course of treatment.

How Is Macrocephaly Treated?

The treatment of macrocephaly depends on the cause of the condition. Options include:

  1. Surgery is often the only option in several causes of macrocephaly. The type of surgery will vary according to the extent of swelling and the reason. For instance, hydrocephalus involves draining the cerebrospinal fluid into the abdomen where the body can absorb it. This surgery is called shunt surgery, where a silicon tube is placed in brain fluid on one side and abdominal cavity on another side. But it does not cure the condition, as hydrocephalus is a permanent condition. In the case of brain trauma, surgery may help rectify the problem entirely.
  1. The doctor may provide oral medications to control the swelling of the brain tissue. Deficiency diseases like rickets can be cured by giving the baby the right dose of the nutrient.
Oral medications may help manage macrocephaly in babies

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  1. Macrocephaly due to genetic disorders does not have a cure and can only be managed. Several infants with incurable macrocephaly encounter some form of cognitive and physical disability along with complications like seizures.
Be watchful
Seek prompt medical evaluation if the baby has bulging fontanels, is feeding poorly, vomiting, sleeping excessively, or has abnormal eye movements (2).

You can contact support organizations and trainers that specialize in dealing with infants with disabilities. Such resources can help train parents about coping with the condition and improving the infant’s quality of life.

Frequently Asked Questions

1. Can a child with macrocephaly be normal?

Yes. If many individuals in your family have a large head (macrocephaly), your child is meeting overall developmental milestones and has a normal neurologic finding, it can be considered a normal and healthy condition. However, ensure to get your baby checked for any underlying medical condition (9).

2. What are the symptoms of macrocephaly?

In the case of benign familial macrocephaly, the child will have a considerable head size and no other symptoms. Otherwise, you may find symptoms such as rapid head growth, poor appetite, developmental delays, bulging spaces between the bones of your child’s skull, bulging veins on the head, a downward gaze of your child’s eyes, and other conditions such as autism (9).

3. Do babies outgrow macrocephaly?

Benign familial macrocephaly or benign extra-axial collections of infancy are considered harmless, and babies usually grow out of condition by early childhood. However, treatment is required if an underlying medical condition is present along with macrocephaly (9).

Macrocephaly in babies may occur due to the accumulation of excess fluids inside the head, infections causing inflammation, or deficiency diseases such as rickets that affect bones. Some cases may be benign, and the child grows without any health concerns. However, it is important to seek medical advice if your child’s head keeps growing. Corrective surgery may be suggested to drain out the extra fluid or in case of trauma. Reach out to specialized trainers and other resources to ensure a better quality of life for your child.


MomJunction's articles are written after analyzing the research works of expert authors and institutions. Our references consist of resources established by authorities in their respective fields. You can learn more about the authenticity of the information we present in our editorial policy.
1. Data Table of Infant Head Circumference-for-age Charts; Centers for Disease Control and Prevention
2. Macrocephaly; Children’s Hospital at Dartmouth-Hitchcock
3. Large Heads (Macrocephaly); The University of Chicago
4. About Hydrocephalus; Stanford Medicine
5. Vitamin D; University of Rochester
6. Sotos syndrome; U.S. National Library of Medicine
7. Macrocephaly Syndromes; University of Florida
8. K. Rozovsky et al., Fast-brain MRI in children is quick, without sedation, and radiation-free, but beware of limitations; National Center for Biotechnology Information
9. Macrocephaly; Cleveland Clinic

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