What is Microcephaly

Microcephaly is a medical condition in which a child’s head is much smaller than normal. Head size (circumference) is measured as part of a child’s routine checkups.

A child’s head grows while in the womb and during the first few years of life. Your child may be born with microcephaly, or the condition may be diagnosed in the months after birth. It is usually diagnosed by age 2.

Children with mild microcephaly may develop and grow normally. Children with more severe microcephaly often have other nervous system and developmental problems. These children may need therapy and medicines.

What are the causes?

In most cases, this condition is caused by a genetic abnormality that interferes with brain growth. The child’s brain may not have developed normally in the womb, or it might not grow normally after birth. A number of genetic abnormalities have been linked to microcephaly.

Microcephaly may also be caused by things that affect a child’s mother during pregnancy. These may include:

• Use of drugs or alcohol.
• Certain infections, including rubella, chickenpox, HIV, Zika, and toxoplasmosis.
• Exposure to toxic substances, such as lead or mercury.
• Decreased blood supply to the baby.
• Poorly controlled diabetes.
• Untreated phenylketonuria (PKU). This is a condition in which a substance called phenylalanine builds up in the body.
• Hypothyroidism. In this condition, the thyroid gland does not produce enough hormones.
• Vitamin B (folate) deficiency.
• Very poor nutrition (malnutrition).

Other causes of microcephaly may develop after birth. These include:

• Genetic abnormalities that show up after birth.
• Brain injuries.
• Conditions that cause decreased blood supply to the brain.
• Brain infections.
• Lead poisoning.
• Kidney disease.
• Heart disease.
• Malnutrition.

What are the signs or symptoms?

In some children, the only sign of microcephaly is a small head circumference. Children with more severe microcephaly may also have:

• Poor mental development.
• Trouble with coordination and balance.
• Poor control of body movements (cerebral palsy).
• Shortness (dwarfism).
• Abnormal facial features.
• Being overly active and excitable (hyperactivity).
• Seizures (epilepsy).
• Hearing, speech, and eye problems.

How is this diagnosed?

This condition can be diagnosed by measuring a child’s head circumference. Standard charts have been developed to identify normal ranges of head circumference based on the sex and age of a child. Your child’s health care provider may diagnose microcephaly if your child’s head circumference is significantly below what is considered normal.

Your child may need to be checked for signs or symptoms of developmental abnormalities or delays. The child may also need to have tests to determine the cause and severity of microcephaly. These may include:

• Genetic blood tests.
• Imaging tests, such as a CT scan or MRI. These are used to create a picture of the brain.
• Hearing and vision exams.

How is this treated?

Microcephaly is a lifelong condition. There is no treatment that can prevent or reverse it. However, depending on the severity of the condition, treatment may be focused on helping your child grow and develop. You may need to work with a team of health care providers and therapists to address your child’s developmental difficulties. Possible treatments include:

• Medicines to prevent seizures and hyperactivity.
• Physical therapy.
• Speech and language therapy.
• Occupational therapy.
• Genetic counseling.

Follow these instructions at home:

• Give over-the-counter and prescription medicines only as told by your child’s health care provider.
• Encourage your child to be active and to do regular activities as much as possible.
• Make sure you get all the support you need. Dealing with a long-term health condition in your child can be stressful. Ask your child’s health care providers and therapists what types of assistance and support are available.
• Keep all follow-up visits as told by your child’s health care provider. This is important.

Contact a health care provider if:

• Your child does not seem to be growing or developing normally.
• Your child is having trouble with coordination, balance, speech, or hearing.
• Your child seems hyperactive.

Get help right away if:

• Your child has a seizure.
• You are unable to safely take care of your child at home.

Summary

• Microcephaly means that your child’s head is much smaller than other children of the same age.
• Microcephaly can be present at birth or develop over the first few years of life.
• Sometimes, children with microcephaly have problems with learning, muscle coordination, or general development, which may require that they see a team of specialists as they grow.
• There is no cure for microcephaly. Treatment is focused on helping your child grow and develop.