Clinical Features and Management of Cerebral Palsy

Published on 26/03/2015 by admin

Filed under Neurosurgery

Last modified 26/03/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 2793 times

CHAPTER 225 Clinical Features and Management of Cerebral Palsy

Cerebral palsy (CP) is “a group of disorders affecting the development of movement and posture, causing activity limitation, that are attributed to non progressive disturbances that occurred in the developing fetal or infant brain. The motor disorders of cerebral palsy are often accompanied by disturbances of sensation, cognition, communication, perception and/or behavioral and/or by a seizure disorder.”1

The estimated prevalence of CP is 1.5 to 3.0 per 1000 live births worldwide, with differences among countries, racial/ethnic groups, and socioeconomic classes.2,3 In most cases the cause of CP is not well defined, and it may vary with the subtype; prematurity and low birth weight are major risk factors for CP, especially bilateral spastic CP associated with periventricular white matter injury. Although birth asphyxia is uncommon, it is associated with the dyskinetic CP subtypes.3 Multiple genetic and metabolic factors may predispose infants to an increased risk for brain injury and CP.4

Diagnosis and Classification

Children with CP have a delay in motor development and abnormal motor findings on examination. Evaluation begins with a detailed history and physical and neurological examination, including careful documentation of prenatal, perinatal, and neonatal events and risk factors, developmental milestones, family history, general medical history, and a detailed survey to look for associated impairments (e.g., seizures, language disturbance, vision and hearing loss, nutritional difficulties). All CP patients should undergo magnetic resonance imaging, which may help reveal the underlying brain injury,5 although neither imaging nor laboratory tests can prove the diagnosis. An atypical history, clinical features, or imaging findings should trigger further evaluation, especially if there is any history of developmental regression or loss of skills.3,6 Disorders that masquerade as CP include familial spastic paraparesis and dopa-responsive dystonia. Some patients, including those with typical risk factors for CP (twin gestation, prematurity, periventricular leukomalacia) have “CP plus” and are found to have a coexisting metabolic disorder (e.g., mitochondrial encephalomyopathy).

There is currently no universally accepted classification system for CP, but since the mid-1900s, CP has most commonly been classified into “spastic” or “dyskinetic” subtypes based on the predominant type of tone abnormalities or movement disorders, or both, present. Spastic CP is the most common and is further divided into spastic diplegia (legs more than the arms), spastic quadriplegia (arms equal to or more than the legs), and spastic hemiplegia (involvement of one side of the body). Dyskinetic CP is divided into dystonic and choreoathetoid forms. A small subset of patients may be classified as ataxic. However, there is great disparity among practitioners regarding the use of these terms, such that a given patient may be classified differently by different clinicians.7 This is a major weakness in the field, and correcting it is a priority for furthering research and treatment.

In 2000, the Surveillance for Cerebral Palsy in Europe group adopted a standardized system for database and registry purposes that is used throughout Europe and Australia. Patients are classified as “spastic bilateral” or “spastic unilateral.” Individuals with variable tone are classified as “dyskinetic” and then further classified as dystonic or choreoathetoid/hyperkinetic. Those with hypotonia and ataxia are classified as “ataxic.” Some patients are nonclassifiable. Additionally, clinically useful functional scales for both gross motor function (Gross Motor Function Classification Scale [GMFCS],8 Functional Mobility Scale9) and fine motor/hand function (Manual Ability Classification Scale,10 Bimanual Function Measure11) are now available to allow improved description of motor function in patients with CP. A Communication Function Classification System is currently being validated (M. J. Cooley Hidecker, personal communication).

The clinical description of a patient with CP should include a detailed account of the movement disorder and tone abnormalities (e.g., spasticity, dystonia, athetosis, chorea, myoclonus), the presence of abnormally persistent primitive reflexes (startle, asymmetric tonic neck reflex) and absence of protective reflexes (parachute), assessment of muscle strength when possible (although a patient’s inability to isolate specific muscle groups may limit such assessment), topography of the movement disorder (limbs and body parts involved and how they are affected), motor function (including use of the aforementioned scales), and secondary musculoskeletal impairments (osteopenia, fracture, scoliosis, hip dysplasia, muscle contractures, bony deformities) that may further compromise mobility and quality of life. Most patients have multiple impairments. Dissecting out and treating, as possible, the various abnormalities will have the biggest impact on future motor outcome.

Associated Impairments

Although the hallmark of CP is the motor disorder, nearly all children with CP have one or more associated impairments that may impede their functional abilities, health, and overall quality of life; they often prove more detrimental than the motor disability. Associated neurological impairments (e.g., vision, hearing, and sensory deficits, epilepsy) can be attributed to brain/nervous system injury that extends beyond the motor system. Other impairments (e.g., musculoskeletal deformities, contractures, fractures, pain) may be secondary to spasticity, other movement disorders, and immobility. Several health impairments in children with CP may have a neurogenic component and can also be further exacerbated by the impaired mobility (e.g., bladder dysfunction, disorders of intestinal motility, sleep disorders). Every child with CP deserves a systematic and detailed survey to identify associated impairments because appropriate treatment can be life changing.

Neurological Impairments

Sensation

Visual disorders are common in children with CP but are often missed or inaccurately diagnosed.12 Over half of children with spastic CP and no obvious visual deficit will nonetheless have visual perception disorders.13 The severity of the visual deficit tends to correlate with the severity of CP involvement and is increased with a history of prematurity, severity of periventricular leukomalacia, and the presence of dyskinetic CP.12,14

Children with multiple visual impairments are often misdiagnosed as having untreatable “cortical visual impairment,” which leads to devastating consequences on communication, learning, social interactions, and quality of life. True cortical visual impairment affects approximately 16% of patients.12 Detailed assessment may be required to untangle the various contributors to the visual impairment but may lead to dramatic improvement in vision through surgery (e.g., strabismus correction, lens replacement, laser treatment) and corrective lenses.

Hearing impairments occur in approximately 7% of children with CP but are likely to be missed, especially in nonverbal children.

Even children with the mildest spastic CP are likely to have deficits in tactile and proprioceptive sensation,15 and their severity may correlate with the severity of the motor dysfunction.16

Epilepsy

Approximately a third of all children with CP have epilepsy. The prevalence varies with the subtype of CP, from 16% in children with diplegic CP to 50% in those with quadriplegic CP.17 The prognosis depends on the subtype of CP, brain imaging abnormality, and cognitive ability. Children with CP and epilepsy are much less likely to achieve freedom from seizures with or without antiepileptic drugs, and they are more likely to require polytherapy.18

Improving Mobility and Motor Function (“I Want to Walk”): How Do We Help Them?

Improving a child’s ability to move is a major goal for most parents (and children). Children enjoy moving! The secondary consequences of immobility are high. Most children with CP have inadequate physical fitness, which further contributes to their poor health, pain, and secondary impairments.38

Physical and Occupational Therapy

Physical and occupational therapy occurs in many different settings, including traditional (home, school, private clinic) and nontraditional (e.g., therapeutic horseback riding39,40 and adapted sports). The therapist has a pivotal role as a teacher to help patients master new motor skills and teach parents (and older patients) exercises (stretching, strengthening, balance) and adaptive techniques (assistive technology for activities of daily living, access to computers or communication devices) that they can integrate into their daily life.

A variety of new tools are available to the physical therapist, such as electrical stimulation, which may have a positive effect on range of motion,4143 and treadmill training with partial body weight support, which may be beneficial for a moderately severely impaired child (GMFCS III or IV).44 Ankle-foot orthoses are commonly prescribed for children who have a dynamic equinus abnormality, may be more effective in younger children,45 and can improve their ability to perform sit-to-stand transitions.46 The most effective type and “dose” or frequency of physical therapy remains controversial. Recent studies suggest that intermittent bursts of intense therapy for a few weeks with several weeks off between sessions may be as effective as continuous therapy 1 to 2 times per week.47

In the upper extremity, constraint-induced therapy and forced use have re-emerged as a useful tool. In clinical trials, restraint of the child’s better functioning hand/upper limb in combination with occupational therapy improves function in the affected limb (new motor skills and increased dexterity) for at least 6 months.4852 Repeat courses of treatment lead to additional improvement.53 Botulinum neurotoxin (BoNT) combined with occupational therapy is another effective strategy.54 Recent, exciting advances include the use of robotics to improve upper extremity function.55

Therapy programs along with overall management of a child’s hypertonia and mobility impairments must be goal-driven and tailored specifically to each child’s needs (Table 225-1). For example, children with spasticity need regular stretching of spastic muscles to optimize range of motion and prevent contractures. Strengthening exercises to reverse disuse atrophy may improve gait and do not worsen the spasticity.5659 Conversely, in children with generalized dystonia and hyperkinetic CP who are constantly moving or contracting their muscles, both stretching and strengthening may prove impractical if not impossible.

Management of Hypertonia and Spasticity in Children with Cerebral Palsy

Hypertonia is defined as abnormally increased resistance to externally imposed movement about a joint. The Task Force on Childhood Motor Disorders recently developed a consensus definition of spasticity as “hypertonia in which one or both of the following signs are present: (1) resistance to externally imposed movement increases with increasing speed of stretch and varies with the direction of joint movement, and/or (2) resistance to externally imposed movement rises rapidly above a threshold speed or joint angle.”60

Tone reduction may be considered if the hypertonia/spasticity interferes with function, cosmesis, comfort, or care. However, spasticity and hypertonia rarely exist as isolated impairments in children with CP, and many children also have associated weakness (trunk, neck, limbs) and loss of selective motor control. Systemic medications to alleviate hypertonia in the extremities may worsen head and trunk control in patients with quadriplegia or moderate to severe diplegia. Some patients with severe lower extremity hypertonia effectively use their tone to “stand up” on otherwise weak limbs and may lose their ability to participate in transfers after treatment. Thus, a comprehensive team approach that includes physicians, allied health therapists, and the family and patient leads to the best outcome. Treatment goals should be continuously re-examined and revised in accordance with the entire picture, including clinical, home, and school factors.

Oral Medications

Oral medications are often considered the first line of intervention for spasticity despite the fact that none have been approved by the Food and Drug Administration (FDA) or even adequately tested in children. Most studies documenting efficacy were conducted many years ago with less than adequate study designs and no functional measures. Data from more recent trials in adults cannot be directly extrapolated to children. Oral medications are prescribed for patients with widespread spasticity and for those with only mild hypertonia. Although these medications are attractive because of the ease of use, this benefit is often outweighed by side effects, especially sedation.

Diazepam

Diazepam is a benzodiazepine that acts by facilitating the postsynaptic action of GABA. Studies from the 1960s indicate its capacity to reduce spasticity. More recently, Mathew and colleagues compared diazepam with placebo in 180 children and demonstrated its ability to reduce muscle overactivity.66 A comparison of diazepam and dantrolene showed that both agents were equally effective and that a combination of the two was superior to either alone.67 The usual dosage of diazepam is 0.12 to 0.8 mg/kg up to the adult maximum. This dosage is divided into three to four doses across the day. Sedation is a known side effect of the benzodiazepines. Thus, use as a sleep aid may also be an added advantage.

Dantrolene Sodium

Dantrolene inhibits release of calcium from the sarcoplasmic reticulum. In two double-blind, crossover studies, spasticity was reported to be reduced67,68; however, in another placebo-controlled study, the reduction in spasticity could not be verified.69

Buy Membership for Neurosurgery Category to continue reading. Learn more here