Chapter 11. Cerebral Palsy

Cerebral palsy (CP) is a general term used for a group of nonprogressive disorders of movement and posture caused by abnormal development of, or damage to, parts of the brain that control muscle movements.1 The term does not imply severity, cause, treatment, or prognosis. The overall prevalence of the condition ranges from 1.9 to 2.6 of every 1000 live-born children in the Western world.2 The rate of CP is much higher in preterm versus term infants and increases with decreasing birth weight and gestational age. It increases at the extremes of birth weight across gestational ages.3 CP is newly diagnosed in approximately 6000 infants and young children every year in the United States. This overall amount has not changed in the last 20 to 30 years, although recent studies suggest that there may be a decreasing trend.2,4,5

CP is caused by events occurring before, during, or after birth up to age 3 years.6 The etiology is multifactorial. Birth injuries such as hypoxic ischemic encephalopathy, or head injuries after delivery such as those from car accidents, child abuse, falls, or intracranial hemorrhages, can lead to CP. Illnesses such as meningitis in the first few weeks or months of life, or strokes that occur in the newborn period, may result in cerebral palsy. CP is often, but not always, diagnosed in children with congenital cerebral malformations of microcephaly or hydrocephalus. Perinatal asphyxia, intrapartum hypoxia, prematurity, intrauterine growth retardation, intrauterine infection, antepartum hemorrhage, severe placental abnormalities, and multiple pregnancies can all be associated pathologies.7 Unfortunately, the cause is not always clear.8

CP is characterized by abnormalities of movement and posture. Young children are often identified with signs of CP when motor milestones are not met. Children may also have increased (stiffness) and/or decreased tone on the motor exam or asymmetries may be found.

These children may show a lack of muscle coordination when performing voluntary movements. A young child may appear ataxic when ambulating. Spasticity may be noted as the child has stiff or tight muscles in his or her arms and/or legs, exaggerated reflexes, walking with one foot or leg dragging, toe walking, a crouched, or a "scissored" gait, and muscle tone that is either too stiff or too floppy.9 Common terms used to describe the clinical presentation of CP include static encelphalopathy, spasticity, or developmental delay.10

The classification of CP is based on the number of limbs involved and the associated resting tone, or movement abnormalities (Figure 11-1).

Types of Cerebral Palsy

• Spastic CP—Most common type accounting for approximately 80%, is due to pyramidal tract lesions with subsequent rate-dependent increase in tone, hyperreflexia, clonus, and an abnormal Babinski reflex.11 Muscles are stiff, body position may be abnormal, and fine motor control is affected.
• Dyskinetic CP (Athetoid CP, dystonic CP, and choreoathetoid CP)—Extrapyramidal signs characterized by involuntary movements such as twisting, jerking, rigid posturing or other movements; increased tone is often present.11
• Ataxic CP—Abnormal movements involving tremors, unsteady gain, and loss of coordination.
• Mixed CP—May have both hyper and hypotonia and there is often a mixture of spastic and dyskinetic components.6
• Hypotonic CP—Hypotonia in both trunk and extremities with increased reflexes and persistent primitive reflexes; occurs infrequently.6

The location usually of impairment falls into one of three broad categories11:

• Hemiplegia—CP predominantly affecting one side of the body, with the arm usually more impaired than the leg.
• Diplegia—CP affecting bilateral lower extremities; arms may be partially involved.
• Quadriplegia—CP affecting all 4 extremities (full body).

CP may also be termed mild, moderate, or severe, although there are no firm boundaries.

Children with CP usually present with a delay in reaching early developmental milestones. The diagnosis of CP depends upon a combination of findings including motor delay, tone abnormalities, weakness, persistence or asymmetry of primitive reflexes, and abnormal postural reactions. A detailed history and thorough physical and neurological examinations are necessary to rule out other potential causes such as progressive neurodegenerative disorders or other inherited or metabolic diseases. It is important to note that these children are not losing motor skills.

Infants with an abnormal obstetric or perinatal history should be monitored closely as they may be at increased risk to develop CP. Potential findings include abnormal behavior such as excessive passivity or irritability, poor feeding and/or sleeping, and poor visual attention. The baby may be hypotonic or hypertonic, have increased tendon reflexes, and clonus. Primitive reflexes such as fisting may be asymmetric or persistent, and postural reflexes may be exaggerated or their disappearance may be delayed. Oromotor skills may be abnormal with tongue retraction and thrust, tonic bite, oral hypersensitivity, and grimacing. Furthermore, achievement of motor milestones should be evaluated. Serial examination of motor milestones can be an effective screening tool for CP.12,13 It should also be noted that although the damage in CP is nonprogressive, clinical signs develop as the nervous system matures. An absolute diagnosis usually requires repeated examinations and often is not possible until later infancy or early childhood.

Laboratory Tests

No specific studies confirm the diagnosis of CP. Children with unusual components in the history or other abnormalities on physical or neurological examination should be thoroughly evaluated and a metabolic disorder excluded.

Neuroimaging

Imaging studies are useful to identify specific lesions such as periventricular leukomalacia, hydrocephalus, or porencephaly; or developmental abnormalities such as migrational defects or agenesis of the corpus callosum. Magnetic resonance imaging (MRI) of the brain can identify a lesion in the majority of cases of CP and can help determine whether the injury was prenatal, perinatal, or postnatal in occurrence.14-16 However, a normal MRI does not rule out CP.

Metabolic and Genetic Testing

The American Academy of Neurology and the Child Neurology Society recommend in their practice parameter that metabolic and genetic testing be considered if the clinical history or findings on neuroimaging do not determine a specific structural abnormality, or if there are suggestive or atypical features in the history or clinical examination.16

Recommendations

The practice parameter from the American Academy of Neurology and the Child Neurology Society recommends the following approach to the evaluation of the child with CP (Figure 11-2)16:

• The diagnosis of CP is based on a comprehensive history and physical examination. It is important to confirm that there is not a progressive or degenerative condition. It is also important to classify the type of CP.
• Screening for developmental delay/mental retardation, ophthalmologic disturbances, hearing impairment, speech and language problems, and oral-motor dysfunction are advised as part of the initial assessment because these problems are commonly found with CP.
• An EEG is recommended when there are signs or symptoms suggestive of seizures.
• Neuroimaging is advised to establish an etiology and for aiding with prognosis. MRI is preferred to CT scan.
• Metabolic and genetic testing should be considered if evidence of regression or episodes of metabolic decompensation. It should also be considered if an etiology has not been found by the medical work up.

CP is a diagnosis of exclusion. It is important that children with signs or symptoms of CP be evaluated for a possible cause. Muscle weakness may be confused for hypotonia diplegia or quadriplegia; may result from inborn errors of metabolism or degenerative disorders dystonia and choreoathetosis from metabolic disorders; and ataxia may arise from genetic abnormalities. Another diagnosis should especially be considered if there is a positive family history of a neurodegenerative disease or inborn error of metabolism, loss of developmental milestones, worsening during times of illness, sensory loss, or hypotonia with muscle weakness.17 See Table 11-1.

Every child with CP is different in that no two patients have the exact same impairment so treatment must be individualized as well. All treatment should be targeted at improving function and reducing disability. A multidisciplinary team is necessary to address the many needs including social and emotional development, communication, education, nutrition, and mobility as well as achieving maximal independence in activities of daily living. It is also important to keep appearance as nearly normal as possible.18

Treatment of CP may be intervention and preventive based. For example, therapy and the use of adaptive equipment may prevent the patient's spasticity from worsening and evolving to contractures. The goal of most adaptive equipment is focused on preventing tightening of heel cord tendons, preventing scoliosis issues, and preventing bone issues in the non–weight-bearing patient.

Adaptive equipment has the goal of minimizing long-term complications of CP. For example, a footstool at the dining table or in the car can help prevent the "dangling" of feet and helps prevent shortening of the heel cord tendon. High-top shoes may also keep the foot at a 90-degree angle. The therapist may suggest seating support for feeding or various orthotics. Standers help the non–weight-bearing child to have daily periods of weight bearing. Wheelchairs must be fitted and adapted as the child grows to meet the physical and changing needs. For the child with mild CP, the use of a bicycle is also an excellent source of therapy. Trials of hippo therapy have shown beneficial effects on body structures and functioning.19

Many children with CP receive therapy services (Table 11-2) during the school year at school. When summer approaches, many are without therapy. It is important that therapy be maintained throughout the calendar year. In some situations, schools can help the child to have the necessary standers at home during summers and holidays.

Several medications are useful in managing CP (Table 11-3). The most common use of botulinum toxin A (Table 11-4) is for equinous foot deformity.20 Other uses for BtA include crouched gait, pelvic flexion contractures, cervical spasticity, seating difficulties, and UE deformity. Casting after BtA may be done to assist with maximum stretching of injected tendons.

Selective Dorsal Rhizotomy

SSDR is the permanent severing of selective dorsal rootlets in the lumbosacral regions (L1-S2). It is thought that cutting these rootlets decreases spasticity or muscle stiffness by inhibiting the muscle stretch reflex. The role of SDR in spastic quadriparesis is to improve hip stability by preventing progressive lateral migration of the femoral head. (If hip instability is untreated, there is up to a 60% risk of painful hip subluxation and dislocation.) SDR in the child with severe spastic quadriparesis may help reduce tone which may also improve the physical care of the child. The role of SDR in spastic diplegia requires thorough investigation. These patients are less affected by their CP and may do well without SDR. The principle impairment of CP is the inability of the patient to effectively be in command of their muscles and this disability persists even after spasticity is removed.21

Other issues of treatment include time and money for appointments and therapy. The home requires modification. Schools require modification to meet the needs of the child with a disability. The cost of lost wages and the loss of independence may be devastating for some. The estimated yearly cost to care for children with cerebral palsy is $11.5 billion.22

The terms neuromotor dysfunction, developmental delay, motor disability, static encephalopathy, and central nervous system dysfunction are less emotional terms in labeling the condition until certain of diagnosis. However, once the diagnosis of CP is made, much can be done to help the individual reach his or her potential. We, as healthcare providers, need to work with the child and family to help them overcome the challenges they will face and to achieve and maintain a rich and rewarding life.