The term cerebral palsy does not indicate the cause or prognosis of the child with cerebral palsy. There are many possible causes of cerebral palsy.
In full-term infants the cause of cerebral palsy is usually prenatal and not related to events at time of delivery; in most instances it is related to events that happened during the pregnancy while the fetus is developing inside the mother’s womb.
Premature birth is a risk factor for cerebral palsy. The premature brain is at a high risk of bleeding, and when severe enough, it can result in cerebral palsy. Children that are born prematurely can also develop serious respiratory distress due to immature and poorly developed lungs. This can lead to periods of decreased oxygen delivered to the brain that might result in cerebral palsy. A poorly understood brain process observed in some premature infants is called periventricular leukomalacia. This is a disorder in which holes form in the white matter of the premature infant’s brain. The white matter is necessary for the normal processing of signals that are transmitted throughout the brain, and from the brain to the rest of the body.
White matter abnormalities are observed in many cases of cerebral palsy. Nevertheless, it is important to recognize that the vast majority of premature infants, even those born very prematurely, do not suffer from cerebral palsy. There have been many advances in the field of neonatology (the care and study of problems affecting newborn infants) that have enhanced the survival of very premature infants.
Other important causes of cerebral palsy include accidents of brain development, genetic disorders, stroke due to abnormal blood vessels or blood clots, or infections of the brain.
Even though it is widely believed that the most common cause of cerebral palsy is a lack of oxygen to the brain during delivery (birth asphyxia), it is actually a very rare cause of cerebral palsy. When cerebral palsy is the result of birth asphyxia, the infant almost always suffers severe neonatal encephalopathy with symptoms during the first few days of life. These symptoms include:
- feeding and respiratory problems,
- lethargy, and
- coma depending on the severity.
In rare instances, obstetrical accidents during particularly difficult deliveries can cause brain damage and result in cerebral palsy. Conversely, it is very unlikely that cerebral palsy symptoms would develop after a few years of age as a result of obstetrical complications.
Child abuse during infancy can cause significant brain damage which, in turn, can lead to cerebral palsy. This abuse often takes the form of severe shaking from a frustrated parent or caregiver, causing hemorrhage in or just outside the brain. To further compound the problem, many children with developmental abnormalities are at risk for being abused. Thus, a child with cerebral palsy may be made significantly worse or even killed by a single incident of abuse.
Despite the diversity of causes of cerebral palsy, many cases remain without a defined cause. However, the enhanced ability to see the brain structure with magnetic resonance imaging(MRI) and CT scans as well as improved diagnostic capabilities for genetic disorders has made the number of such cases much lower.