Periventricular Leukomalacia
Definition
Periventricular leukomalacia is a brain condition affecting fetuses and newborns in which there is softening, dysfunction, and death of the white matter of the brain.
Description
The brain is composed of outer gray matter and inner white matter. The gray matter is responsible for processing information involved in muscle control, sensory perception, emotion, and memory. The white matter is responsible for transmitting information throughout the brain, to the spinal cord, and outside of the brain to the muscles. The ventricles are four cavities within the brain, all of which are interconnected with each other and with the central spinal canal, and through which the cerebrospinal fluid circulates. "Periventricular" refers to the white matter that surrounds the ventricles. "Leukomalacia" means softening of the white tissue. When the white matter softens, the brain tissue begins to die.
Demographics
Periventricular leukomalacia strikes fetuses and newborns, particularly those who have undergone some kind of oxygen deprivation, such as may occur due to complications of prematurity. Some 4–26% of all premature infants in neonatal intensive care units have evidence of periventricular leukomalacia. As many as 76% of premature infants who die of complications of prematurity have evidence of periventricular leukomalacia on autopsy.
The risk of a baby developing periventricular leukomalacia is higher in those babies with smaller birth weights, who are twins, who are born at less than 32 weeks and require mechanical ventilation, and/or who are born of mothers who have abused cocaine. The following conditions also increase a baby's likelihood of developing periventricular leukomalacia:
- low blood pressure
- increased acidity of the blood
- high blood pressure
- low blood carbon dioxide
- abnormalities of the placenta
Causes and symptoms
Premature babies are at high risk of a variety of complications, including low blood oxygen (hypoxemia), decreased delivery of oxygen to the body's tissues (hypoxia), and/or decreased flow of oxygen-rich blood to the body's tissues (ischemia). All of these complications can result in oxygen deprivation of the susceptible newborn brain tissue, and potentially in subsequent brain damage. Without a constant flow of enough oxygen and nutrients, the oxygen-starved brain tissue will begin to soften and die. Additionally, premature infants have a very high risk of bleeding into the brain (intraventricular hemorrhage). When this occurs, the area around the brain hemorrhage is particularly susceptible to periventricular leukomalacia.
Other risk factors for periventricular leukomalacia include early rupture of the amniotic membranes (the birth sac) prior to delivery of the baby, and infections within the mother's uterus during pregnancy and/or labor and delivery of the baby.
Symptoms of periventricular leukomalacia include tight, contracted, spastic leg muscles, delayed motor development, delayed intellectual development, problems with coordination, impaired vision and hearing, and seizures. More than 60% of all babies who have periventricular leukomalacia will actually develop cerebral palsy, particularly if the periventricular leukomalacia has been accompanied by intraventricular hemorrhage. Cerebral palsy is a constellation of symptoms that occur due to significant oxygen deprivation of the brain tissue, resulting in lifelong difficulties with coordination between the brain and muscles, and sometimes accompanied by mental retardation.
