Cerebral palsy: not always what it seems.

Cerebral palsy (CP) is an umbrella term that defines a group of non-progressive, but often changing, syndromes of motor impairment secondary to lesions or anomalies of the brain arising in the early stages of its development. 2 The characteristic clinical feature that is common to all CP syndromes is the presence of pyramidal or extrapyramidal signs. CP is neither a specific disease nor a pathological or aetiological entity, and importantly the term CP does not—and should not—necessarily imply or identify a specific cause. The prevalence of CP ranges from 1.5 to 2.5 per 1000 live births, with the risk highest among very preterm and low birthweight babies. However, the majority of children with CP are born at or near term gestation. Causes of CP include perinatal hypoxic-ischaemic encephalopathy, intraor periventricular haemorrhage, cerebral dysgenesis, and intracranial infection. The CP syndromes may be classified by the predominant type of motor disturbance, including, for example, diplegia, tetraplegia, hemiplegia, dyskinesia, and ataxia, although frequently the overall clinical picture is not always pure. Finally, the aetiologies for these diVerent syndromes tend to be quite distinct. Once a diagnosis of CP has been made on the basis of the child’s symptoms and signs, each child should undergo appropriate evaluation and investigation to try and establish a cause and specifically to determine whether it is of prenatal, perinatal, or postnatal origin. Investigation is indicated even when there has been evidence of a preceding neurological event during the perinatal period or infancy, because some of these children may have an underlying neurological or metabolic disorder which may have made them more vulnerable to the stresses of delivery and extrauterine life. Finally, it is important that all children with a diagnosis of CP should be followed up, and when no obvious cause has been identified or there is any evidence of regression, children should be referred to a paediatric neurologist. A number of neurodegenerative, including metabolic and genetic disorders may present with similar symptoms and signs. Some of these disorders which are slowly progressive are more likely to be misdiagnosed as CP. Individually these disorders may be rare, but collectively they are not. It is important that these disorders are correctly diagnosed as early as possible for a number of reasons. Firstly, some may be treatable; secondly, the family can be provided with more accurate information regarding the prognosis; and finally, genetic counselling may be oVered, including, where appropriate, prenatal testing. Table 1 lists the more common diseases which have not infrequently been misdiagnosed as CP, both in our experience and that of others. This is not a comprehensive list.