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.
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.
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.
Periventricular leukomalacia can be diagnosed through cranial ultrasound, which allows the brain to be examined using ultrasound techniques through the soft spots, or fontanelles, in the baby's skull. When a baby has periventricular leukomalacia, the ultrasound exam will reveal cysts (fluid-filled compartments) or empty cavities within the brain tissue. Magnetic resonance imaging (MRI) scans of the brain may also reveal the characteristic abnormalities of periventricular leukomalacia.
Most premature babies are treated by a perinatologist (a specialist in the care of premature infants). A pediatric neurologist may be consulted if a baby is suspected of having periventricular leukomalacia or intraventricular bleeding.
There is no cure for periventricular leukomalacia. Efforts, instead, are made to help affected children reach their full potential through a variety of modalities throughout childhood.
Recovery and rehabilitation
The rehabilitation team will depend on the extent of a child's physical and intellectual challenges. Physical therapy, occupational therapy, speech and language therapy, and a specialized educational setting may all be necessary.
The prognosis for babies with periventricular leukomalacia is quite variable, and is dependent on the other complications of prematurity that a baby may face. Deficits may range from mild to devastating disability or even death.
Some studies have suggested that the risk of periventricular leukomalacia is decreased by the administration of steroids to women in premature labor. Other preventive measures include any steps that may decrease the likeli-hood of intraventricular hemorrhage, such as careful labor management and monitoring, and care in an experienced neonatal intensive care unit.
DeGirolami, Umberto, Douglas C. Anthony, and Matthew P. Frosch. "The Central Nervous System." In Robbins Pathologic Basis of Disease, edited by Richard E. Behrman, et al. Philadelphia: W.B. Saunders Company, 1999.
Stoll, Barbara J., and Robert M. Kliegman. "Nervous System Disorders." In Nelson Textbook of Pediatrics, edited by Richard E. Behrman, et al. Philadelphia: W.B. Saunders Company, 2004.
Okumara, A. "Abnormal Sharp Transients on Electroencephalograms in Preterm Infants with Periventricular Leukomalacia." Journal of Pediatrics 143, no. 1 (July 1, 2003): 26–30.
Sofue, A. "Sharp Wave in Preterm Infants with Periventricular Leukomalacia." Pediatric Neurology 29, no. 3 (September 1, 2003): 214–217.
National Institute of Neurological Disorders and Stroke (NINDS). Periventricular Leukomalacia Fact Sheet. (May 23, 2004). <http://www.ninds.nih.gov/health_and_medical/disorders/periventricular_leukomalacia.htm>.
Rosalyn Carson-DeWitt, MD