Cerebral palsy (CP) refers to a group of nonprogressive
neurologic conditions defined by
specific motor deficits or movement disorders.
It is often associated with other systemic
sequelae. Because 65% to 90% of children
with CP survive into adulthood,1 it is important
for clinicians—whether they have a pediatricor
adult-based practice—to understand the
multisystemic nature of CP.
The incidence of CP is relatively low.2 Prevalence in surviving neonates is about 0.2%, and CP has been reported to account for 2% to 8% of office visits to the pediatric neurologist.2 The spastic types are the most common,3 followed by the ataxic and athetoid types. Visits to the doctor are often precipitated by comorbidities involving organ systems other than the nervous system.
Historically, CP was thought to be associated with birth trauma. Although the percentage of CP cases attributable to birth asphyxia is debatable, Nelson and Ellenberg4 estimated that 6% to 7% of cases result from asphyxia at birth and that the cause of 80% of cases has to do with prenatal complications. Congenital, genetic, inflammatory, anoxic, traumatic, toxic, and metabolic causes all have been implicated as causes of CP. Prenatal risk factors include intrauterine infections; chorioamnionitis; fetal thrombophilia; exposure to teratogens; placental complications; multiple births; and maternal conditions such as mental retardation, history of seizures, and hyperthyroidism. New models that look at the inflammatory-mediated model of CP and its developmental sequelae are being developed.5
Perinatal events such as preterm birth, low birth weight, intracranial hemorrhage, infection, seizure, hypoglycemia, and hyperbilirubinemia are well-known risks for neurologic sequelae. Careful developmental and neurologic screening is warranted in pediatric patients who have been affected by these conditions in the perinatal period. Furthermore, accurate determination of the cause of CP has specific implications for prevention in future pregnancies, treatment, prognosis, and medicolegal issues.
History and Physical Examination. Parents' and pediatrician's concerns about abnormal motor development provide the first clue to a possible diagnosis of CP and may initiate referral to a pediatric neurologist. The history may reveal risk factors; findings from the physical examination may identify the type of CP. For guidance on the diagnostic assessment of the child with CP see "Practice parameter: diagnostic assessment of the child with cerebral palsy: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society," which was authored by Ashwal and colleagues and appeared in Neurology in 2004.6
The traditional diagnostic approach consists of early assessment of impairments in muscle tone, strength, and control; assessment of involuntary movements; asymmetry; persistence of primitive reflexes; and late development of postural responses. Note that only about one quarter of children aged 7 years who have CP have a history of an abnormal neurologic examination at birth.7
In reviewing the differential diagnosis, conditions such as metabolic disorders should not be overlooked. Be aware that genetic syndromes such as Lesch-Nyhan syndrome can mimic CP. Consider them in the differential diagnosis if the pregnancy and birth history are unremarkable.8
CP also can be detected based on functional limitations. Estimating functional limitations using the motor quotient (motor age divided by chronologic age multiplied by 100) is one diagnostic tool. A motor quotient below 50 is predictive of gross motor delay.9
Neuroimaging. Neuroimaging is recommended in the evaluation of a child with CP if the cause has not been previously established by perinatal imaging. MRI is preferred to CT because this form of imaging is more likely to identify a cause.6,10 Cranial ultrasound is recommended for infants between 7 and 14 days old and near term-corrected age to identify intraventricular hemorrhage, periventricular leukomalacia, and low-pres- sure ventriculomegaly.
Other Investigations. When an asphyxial episode during gestation is suspected, cord and serum laboratory studies (ie, hemoglobin/hematocrit, platelet count, pH, liver, and renal function tests) are available to help make a determination of timing and severity of the insult. Metabolic and genetic studies should not be routinely ordered but should be considered when clinical history or findings and neuroimaging do not identify a specific structural abnormality.6 Coagulation studies should be obtained in hemiplegic CP.6 A genetics consultation may be useful to further evaluate specific conditions and dysmorphologies in which CP is one characteristic. An electroencephalogram should be obtained only when a child with CP has a history suggestive of epilepsy.6