When is hemimegalencephaly diagnosed?
Ultrasound diagnosis: There is cerebral overgrowth and ventriculomegaly of one hemisphere resulting in shift in the midline in the standard transverse view of the fetal head. The diagnosis is usually made >26 weeks’ gestation. There are always abnormalities of sulcation, including agyria, pachygyria, or polymicrogyria.
How is hemimegalencephaly diagnosed?
In general, the presence of HME is definitively diagnosed by brain MRI. With the evolution of more widespread fetal imaging including ultrasound and MRI, a number of HME cases are detected prenatally.
Can hemimegalencephaly cause death?
Although there have been a few reports of medical treatment, the main treatment is radical: remove or disconnect the affected side. However, it has a high mortality, and there have been reports of a vegetative state and seizures resuming, this time in the healthy hemisphere.
What causes hemimegalencephaly?
Hemimegalencephaly is a rare condition that causes one half of the brain to be abnormally larger than the other. This is associated with frequent seizures that often lead to developmental delay. These seizures poorly respond to medications.
How many cases of Hemimegalencephaly are there?
Hemimegalencephaly (HME) is a rare congenital malformation of the brain characterized by overgrowth of one hemisphere. [1] Its prevalence ranges from 1 to 3 cases/1000 epileptic children and 1–14% among those with cortical developmental abnormalities.
What causes fetal brain defects?
Congenital brain defects may be caused by inherited genetic defects, spontaneous mutations within the genes of the embryo, or effects on the embryo due to the mother’s infection, trauma, or drug use. Early in fetal development, a flat strip of tissue along the back of the fetus rolls up to form a tube.
Can you operate with half a brain?
A hemispherectomy is a rare surgery where half of the brain is either removed or disconnected from the other half. It’s performed on children and adults who have seizures that don’t respond to medicine.
What is a functional hemispherectomy?
A functional hemispherectomy is an evolution of the anatomic hemispherectomy in which less brain is removed, however the diseased hemisphere of the brain is completely disconnected from the normal hemisphere of the brain.
How is hemimegalencephaly treated?
Because the seizures associated with hemimegalencephaly are difficult to treat with anticonvulsant medications, a surgery called hemispherectomy is often the most successful treatment.
What is Megalencephaly?
Megalencephaly, also called macrencephaly, is a condition in which an infant or child has an abnormally large, heavy, and usually malfunctioning brain. By definition, the brain weight is greater than average for the age and gender of the child.
Is it normal for one side of your brain to be bigger?
Sometimes one side of the brain is larger than the other and malformed, a condition called hemimegalencephaly. If one side is larger but not malformed compared to the smaller side, this would be referred to as asymmetry.