Cerebral Palsy is not one particular disease that is able to be pinpointed to one origin; instead, a term used to encompass a variety of disorders that very likely stem from different causes. However, it is generally believed that Cerebral Palsy is a disorder caused by damage to the brain before, during, or after birth.
While a small percentage of children who have Cerebral Palsy acquire the disorder postnatally, or after birth, most cases are caused stem from prenatal or perinatal causes (Cerebral Palsy and Special Needs Children’s Organization). 75% to 90% of Cerebral Palsy cases fall in the prenatal or perinatal category, while only 10% to 25% of these cases occur postnatally.
The following are considered to be possible prenatal causes of Cerebral Palsy because each of them has the potential to impair the development of the fetus’s brain:
- Congenital malformation
- Maternal seizures
- Maternal bleeding
- Exposure to radiation
- Environmental toxins
- Genetic abnormalities
- Intrauterine growth restriction
- Infections
- Nutritional deficits
- Pre-eclampsia
- Multiple births
- Prematurity
- Low birth weight
- Abnormalities of blood flow to the brain
- Malformations of brain structure.
Congenital malformations, maternal infections, chromosomal abnormalities, multiple pregnancies, and pre-birth hemorrhages may result in improper brain development or a reduction of oxygen flow to the developing fetus.
Maternal infections may result in fever and infection of the placenta.
Intrauterine growth restriction can be caused by fetal, placental, and/or maternal causes. Fetal causes of intrauterine growth restriction include infections, inborn errors of metabolism, and chromosomal anomalies. Placental causes of intrauterine growth restriction include placenta previa, abruptio placenta, multiple gestations, and abnormalities in umbilical cord insertion. Maternal causes of intrauterine growth restriction include nutritional problems; hypoxic conditions resulting from lung and heart disease; vascular problems; renal disorders; and outside causes including drugs, infection, and smoking.
Some prenatal causes of cerebral palsy are time dependent in terms of damage. For example, maternal hypertension has been linked to increased incidence of cerebral palsy in very preterm infants. Children who experience a reduction of blood flow before 32 to 34 weeks' gestation may suffer from damage to the white matter of the brain as well as intraventricular hemorrhage.
The following are believed to be perinatal cases of Cerebral Palsy due to their ability to cause damage to the fetus’s brain during delivery:
- Prematurity (less that 32 weeks' gestation)
- Asphyxia (too little oxygen at birth)
- Hypoxia (too much oxygen at birth)
- Breech presentation
- Sepsis/central nervous system infection
- Ischemia (fetal bradycardia)
- Placental complications
- Chorioamnionitis
- Kenicterus
- Electrolyte disturbances
- Cerebral hemorrhage
- Perinatal infection
- Low birth weight
- Delayed onset of breathing
- Maternal fever during labor
Infants who have developed cerebral palsy prenatally and are carried to term may suffer from hypoxic-ischemic encephalopathy. This is the result of low oxygen levels and decreased blood flow to the brain, which causes the death of nerve cells. Often, the result of this is seizures, brain swelling, hypotonia; electroencephalogram abnormalities; and abnormal functioning of the kidneys, heart, lungs, and liver.
Low birth weight indicates a possible problem with normal development. It is frequently associated with cerebral palsy when the infant has low birth weight but is full term (as opposed to low birth weight and premature).
In premature, low-birth-weight infants, the incidence rate of Cerebral Palsy ranges from 15% to 35% in children weighing less than 2,500g. Preterm infants are 10 to 20 times more likely to have cerebral palsy than full-term infants are for the following reasons:
- Prematurity is often accompanied by a lack of development of the respiratory system, which can cause reduced oxygen supply to the fetus
- Prematurity can be associated with cerebral hemorrhage causing brain damage.
- Prematurity also may be associated with maternal infection called chorioamnionitis, and there seems to be a substantial association between cerebral palsy and chorioamnionitis.
The following are believed to be postnatal causes of Cerebral Palsy:
- Head trauma
- Neonatal seizures
- Toxins
- Viral/bacterial central nervous system infections
Head trauma can be associated causes such as vehicle accidents and child abuse that result in brain damage.
Viral/bacterial central nervous system infections (often meningitis or encephalitis) also can be associated with postnatal onset of cerebral palsy. Depending on the severity and length of infection, the resulting central nervous system damage can range from mild to severe manifestations in motor, intellectual, and associated conditions (eg, vision, seizures, hearing problems).
Seizures also can result in postnatal onset of cerebral palsy. This possible cause also depends on the frequency, length, and cause of the seizures as well as if they can be brought under control. Seizures that are not controlled may cause additional brain damage, resulting in gradually more severe manifestations of cerebral palsy.
(Griffin, Fitch, Griffin, 2002)
