What is microcephaly?
Microcephaly is a condition in which a baby’s head is smaller than average for an infant’s size and age. The baby is either born with a smaller head (congenital), or the condition develops as the baby gets older (acquired). Microcephaly is rare, occurring in 2-12 babies per 10,000 births.
Symptoms and Causes
What causes microcephaly?
The exact causes of microcephaly are not known. Microcephaly occurs most often because the brain fails to grow at a normal rate. This can be caused by a variety of conditions or by exposure to harmful substances during fetal development. Some of these causes include:
- Genetic (inherited) disorders such as Down syndrome.
- Viral infections in the mother, such as rubella (German measles), toxoplasmosis (an infection caused by a parasite), cytomegalovirus (a common virus that can cause health problems for fetuses), and Zika virus (a virus transmitted by mosquitoes).
- Alcoholism or drug abuse in the mother.
- Gestational diabetes.
- Poisoning from mercury or other metals or poisons.
- Maternal malnutrition (the mother doesn’t get enough food or nutrients while pregnant).
Acquired microcephaly might occur after birth because of various brain injuries caused by a lack of oxygen or infection.
What are the symptoms of microcephaly?
Aside from a noticeably smaller head, the following are the most common symptoms of microcephaly:
- A high-pitched cry.
- Feeding problems.
- Hearing and vision problems.
- Convulsions (seizures).
- Increased movement of the arms and legs (spasticity).
- Hyperactivity (overly active).
- Developmental delays, or problems learning how to speak, stand and walk.
- Intellectual disabilities (trouble with learning).
As the child grows older, his or her face continues to grow while the skull does not. This causes the child to develop a large face, a receding forehead and a loose, often wrinkled scalp. The rest of the body is often underweight and smaller than normal.
Some babies have no visible or noticeable symptoms. Also, some children who have microcephaly go on to develop normally.
Diagnosis and Tests
How is microcephaly diagnosed?
Microcephaly can sometimes be diagnosed before birth by prenatal ultrasound. In order to make the diagnosis while the fetus is still in the uterus, the ultrasound should be done late in the second trimester or in the third trimester.
After the baby is born, microcephaly can be diagnosed by measuring the baby’s head circumference (all the way around) and comparing it with normal head sizes of newborns. The doctor will also perform a complete physical examination and obtain a complete prenatal and birth history of the child. The doctor might ask the parents about developmental milestones such as crawling and walking, since microcephaly is often accompanied by intellectual disabilities.
Management and Treatment
How is microcephaly treated?
There is no cure for microcephaly, and it lasts the child’s entire life. The medical team works with the child's family to provide education and guidance to improve the health and well-being of the child.
The full extent of microcephaly on the child is usually not completely understood until the child grows and develops. Management of microcephaly involves:
- Frequent examinations and testing to monitor the development of the head as the child grows.
- Treating the child’s ongoing health problems.
- Maximizing his or her capabilities at home and in the community. This might include speech, occupational and physical therapies.
Outlook / Prognosis
What is the prognosis (outlook) for a child who has microcephaly?
The prognosis for a child who has microcephaly depends on the other medical conditions the child has. In general, life expectancy for children who have microcephaly is reduced, and the prospects of attaining normal brain function is poor.
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