I. Description of the problem. Cerebral palsy (CP) is a disorder of movement and posture, causing activity limitation, due to a static defect or lesion of the developing brain. Rather than a specific diagnosis, it encompasses a spectrum of neurodevelopmental syndromes characterized by persistent motor delay, abnormal neuromotor examination, and often an extensive range of nonmotor-associated disabilities in cognitive, neurobehavioral, neurosensory, orthopedic, and other areas. These associated disabilities reflect the fact that motor centers of the brain are rarely affected in isolation. CP, a clinical diagnosis, may be due to a wide range of genetic and environmental insults to the developing brain. When the clinical diagnosis of CP is established, it is important to investigate the etiology, which may be important to treatment, prognosis, risk of recurrence, and parental understanding. Although the brain lesion is, by definition, nonprogressive, its motor and nonmotor manifestations can be expected to change with the child’s development. Therefore, careful ongoing medical and rehabilitation surveillance is necessary.
A. Epidemiology.
About 2-3 per 1000 live births (half-born at term, half-born preterm)
Evidence over the 1980s of an increase in CP birth prevalence in very low-birth-weight babies (with a decrease in mortality in this group), and a probable decrease during the late 1990s.
B. Classification. Clinical classification is based on the nature of the movement disorder, muscle tone, and topography. Classification by type is essential to management and anticipation of associated disabilities (Table 34-1) and future needs.
1. Spastic CP (65% of children with CP). Most children with CP have spasticity, an upper motor neuron syndrome consisting of persistent velocity-dependent hypertonus (increased muscle tone of clasp-knife character), increased deep tendon reflexes, pathologic reflexes, spastic weakness, and loss of motor control and dexterity. Spastic CP is further classified on the basis of topography:
a. Hemiplegia (30% of children with CP). Primary unilateral involvement, often with the arm more involved than the leg.
b. Quadriplegia (5% of children with CP). Four-limb involvement with legs often more involved than arms but with functionally limiting arm involvement.
c. Diplegia (30% of children with CP). Four-limb involvement with legs much more involved than the arms (which may show only minimal impairment and no functional limitation). Diplegia should be distinguished from “paraplegia,” which implies entirely normal arm function and suggests a spinal cord lesion, not CP.
2. Dyskinetic CP (19% of children with CP). The other major physiologic category is designated “dyskinetic” due to the prominent involuntary movements, fluctuating muscle tone, or both. Choreoathetotic and dystonic are the two most common subtypes. Most children with dyskinetic CP have relatively symmetric four-limb involvement and require no further topographic designation.
3. Ataxic CP (up to 10% of children with CP). This type of CP often has genetic underpinnings and is associated with significant comorbidities in vision, hearing, cognition, feeding, and epilepsy.
4. Worster-Drought syndrome (bulbar CP) should be considered in the child whose motor disability is primarily of a cranial nerve distribution. It may be associated with underlying perisylvian microgyria on neuroimaging and may be familial.
C. Etiology/contributing factors. Despite more than a century of research, specific etiologic factors responsible for the motor impairment remain uncertain in many children with CP, especially in children born at term. Large studies have shown that brain injury occurring at birth is the cause in only 8%-12% of cases. Developmental brain anomalies or prenatal insults are the most common etiologies. In premature children, both prenatal and perinatal factors are felt to play a role in what is most commonly a spastic diplegia or quadriplegia. Postneonatal etiologies (e.g., traumatic brain injury, meningitis) account
for about 10% of CP. Maternal and/or fetal infection/inflammation has been noted as an important antecedent of CP in term and preterm infants. Thrombophilia, including the Factor V Leiden mutation, the most common cause of familial thrombosis in neonates, infants and children, may be an important contributor to intrauterine stroke and hemiplegic CP. Advances in neuroimaging and molecular genetics are greatly improving our understanding of etiology and options for prevention.
Table 34-1. Selected nonorthopedic-associated disabilities in cerebral palsy
Cognition
Intellectual disability (present in 30%-77%)
The most important factor influencing habilitation
Hemiplegia and diplegia associated with higher cognition
Easy-to-underestimate cognition in choreoathetosis
Epilepsy associated with lower cognition
Language disorder, learning disability (present in about 40%)
Heterogeneous group with deficits due to oromotor dysfunction, dysphasia, hearing loss
Often “superimposed” on intellectual disability
Very high risk for learning disability in child with CP and “normal” IQ
Neurobehavior (present in up to 50%)
Entire spectrum of neurobehavioral disorders (attention-deficit/hyperactivity disorder to autism) seen
No symptom is “typical”
Behavior dysfunction may be primarily a neurologic symptom or reflect discomfort from underlying medical problems (e.g., GERD, hip subluxation, skin breakdown)
Sensation
Visual disorders (present in 50%-90%)
Most common ones amenable to treatment
May have a bearing on education (acuity, field deficits)
Hemianopsia in 25% of hemiplegia (easily missed as gaze may compensate to side of field cut)
Refractive errors seen in 50% overall, 67% in diplegia; amblyopia develops in 14%
Hearing disorders (present in 10%) easily missed
Higher prevalence (45%-60%) in postkernicteric
Choreoathetosis and TORCH etiologies
Somatosensation (present in up to 50% of hemiplegia)
Deficits in stereognosis most common
May be the limiting factor in arm/hand functioning in hemiplegia
Repeated clinical examination essential to recognition
Associated with linear undergrowth but not muscular atrophy
Seizures (present in 30%-40%)
Often associated with spasticity and lower cognition
Growth failure
Undernutrition a frequent problem
Empiric nutritional goal of 10% weight for height
Multifactorial in origin: increased caloric needs, oromotor dysfunction, gastroesophageal reflux, chronic infection, “neurogenic,” syndromic
Limb length asymmetry associated with hemisensory abnormalities
Other health problems
Genitourinary complaints common; pathogenesis unclear
Drooling a major cosmetic problem: may be exacerbated by antispasticity drugs; treatment with anticholinergics, surgery, and biofeedback disappointing
TORCH, toxoplasmosis, other, rubella, cytomegalovirus, herpes simplex; GERD, gastroesophageal reflux disease.
II. Making the diagnosis. Attention should be given to both developmental diagnosis (type and severity of CP) and etiological diagnosis.
A. Symptoms. CP usually presents with significant motor delay, although the delay may not be recognized in the first months of life. Common presenting concerns include poor head
control, hypertonia (especially during activities such as bathing or diapering), generalized hypotonia, early preferential hand use, absent weight bearing, and feeding problems. Experienced observers may note abnormalities in spontaneous general movements during the first weeks of life.
The nonprogressive nature of “the lesion” is essential to the diagnosis of CP. If etiology is not clear or if an atypical clinical picture includes loss of skills, hepatosplenomegaly, sensory disturbances, or other unusual findings, then evaluation for a progressive process (metabolic, structural, neurodegenerative, etc.) should be undertaken. This generally requires assistance from a subspecialist.
B. Neurologic signs.
1. Sole reliance on the neuromotor examination in diagnosing CP can lead to both under-and overdiagnosis. Instead, the clinician should initially focus on the presence or absence of motor delay.
If there is no delay, CP is unlikely even if the neuromotor examination is abnormal (although children with such “minor neuromotor dysfunction” may have other neurodevelopmental disabilities, such as intellectual or learning disability). An exception to this “no motor delay, no CP” rule is seen in hemiplegia, in which the prominent upper extremity disability may cause substantial neuromotor asymmetry rather than gross motor delay. Focusing on upper extremity function will clearly identify these children.
2. On neuromotor examination, muscle tone may vary from excessive hypotonia to hypertonia (spastic, dystonic, or mixed in character). Hypotonia in an infant may be manifest as head lag on pull to sit, slip through at the shoulders, or an exaggerated curve in ventral suspension. Hypotonia with significant weakness and diminished tendon reflexes is uncommon in CP and suggests a neuromuscular disorder. Early hypotonia may persist, normalize, or evolve into hypertonia.
3. Recognition of abnormal spontaneous general movements during the first weeks of life may provide a sensitive tool for early detection of CP based on the continuing studies in the Europe.
4. Spastic hypertonia—persistent clasp-knife catch or “hitch” is a component of the upper motor neuron syndrome and is brought out by rapid movement of the limb by the examiner.
5. The hypertonus seen in dyskinetic forms is variable in nature and can usually be “shaken out” by the examiner with rapid movements of the limb. Involuntary movements, such as choreoathetosis, dystonic posturing, and tremor, may be associated. Facial and oromotor involvements are often prominent.
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Cerebral Palsy
Cerebral Palsy
Frederick B. Palmer
Alexander H. Hoon
