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Cerebral palsy refers to a group of symptoms including poor muscle control, spasticity, paralysis, and other neurologic problems resulting from brain injury before, during, or shortly after birth.
Cerebral palsy affects 2 to 4 of every 1,000 infants, but it is 10 times more common among premature infants. It is particularly common among infants of very low birth weight.
Cerebral palsy is not a disease. Rather, it is a constellation of symptoms that results from damage to the parts of the brain that control muscle movements (motor areas). Sometimes children who have cerebral palsy have damage to other parts of the brain as well. The brain damage that results in cerebral palsy may occur during pregnancy, during birth, after birth, or in early childhood. Once the brain damage has occurred, it does not get worse even though the symptoms may change as the child grows and matures. Brain damage occurring after age 5 is not considered cerebral palsy.
Causes
Many different types of injury to the brain can cause cerebral palsy, and often more than one cause is involved. Birth injuries and poor oxygen supply to the brain before, during, and immediately after birth cause 15 to 20% of cases. Prenatal infections, such as rubella, toxoplasmosis, or cytomegalovirus infection, sometimes result in cerebral palsy. Premature infants are particularly vulnerable, possibly in part because the blood vessels of the brain are poorly developed and bleed easily. High levels of bilirubin in the blood can lead to a form of brain damage called kernicterus. During the first years of life, severe illness, such as inflammation of the tissues covering the brain (meningitis), sepsis, trauma, and severe dehydration, can cause brain injury and result in cerebral palsy.
Symptoms
The symptoms of cerebral palsy can range from barely noticeable clumsiness to severe spasticity that contorts the child's arms and legs, requiring mobility aids, such as braces, crutches, and wheelchairs.
There are four main types of cerebral palsy: spastic, athetoid, ataxic, and mixed. In all forms of cerebral palsy, speech may be hard to understand because the child has difficulty controlling the muscles involved in speech. Because non-motor parts of the brain also may be affected, many children with cerebral palsy have other disabilities, such as mental retardation/intellectual disability, behavioral problems, difficulty seeing or hearing properly, and seizure disorders.
In the spastic type, which occurs in over 70% of children with cerebral palsy, the muscles are stiff and weak. The stiffness may affect both arms and both legs (quadriplegia), mainly the legs and lower part of the body (paraplegia or diplegia), or only the arm and leg on one side (hemiplegia). The affected arms and legs are poorly developed, stiff, and weak. Some children may walk in a criss-cross motion, where one leg swings over the other (scissors gait), and some may walk on their toes. Crossed, lazy, or wandering eyes (strabismus) and other vision problems may occur. Children with spastic quadriplegia are the most severely affected. They commonly have mental retardation/intellectual disability (sometimes severe) along with seizures and trouble swallowing. Trouble with swallowing makes these children prone to choking on secretions from the mouth and stomach (aspiration). Aspiration injures the lungs, causing difficulty breathing. Repeated aspiration can permanently damage the lungs. Children with spastic diplegia usually have normal mental development and rarely have seizures. About one fourth of children with spastic hemiplegia have below-normal intelligence, and one third of them have seizures.
In the athetoid type, which occurs in about 20% of children with cerebral palsy, the muscles spontaneously move slowly and without normal control. Movements of the arms, legs, and body may be writhing, abrupt, and jerky. Strong emotion makes the movements worse, and sleep makes them disappear. Children with the athetoid type usually have normal intelligence and rarely have seizures. Difficulty with articulating words clearly and normally is common and is often severe. Children with the athetoid type that is caused by kernicterus commonly have nerve deafness and difficulty looking upwards.
In the ataxic type, which occurs in about 5% of children with cerebral palsy, coordination is poor and movements are shaky. Children with the ataxic type also have muscle weakness and trembling. Children with this disorder have difficulty making rapid or fine movements and walk unsteadily, with their legs widely spaced.
In the mixed type, two of the above types, most often spastic and athetoid, are combined. This type occurs in many children with cerebral palsy. Children with mixed types may have severe mental retardation/intellectual disability.
Diagnosis
Cerebral palsy is difficult to diagnose during early infancy. As the baby matures, poor development, weakness, spasticity, or lack of coordination becomes noticeable. Although laboratory tests cannot identify cerebral palsy, a doctor may perform blood tests and computed tomography (CT) or magnetic resonance imaging (MRI) of the brain to clarify the nature of the brain damage and to look for other disorders. The doctor might recommend additional testing, such as electrical studies of nerves (nerve conduction) and muscles (electromyography) or a muscle biopsy (a small piece of muscle tissue is taken and examined under a microscope), if the child's symptoms appear to be evolving in a way not typical of cerebral palsy. The specific type of cerebral palsy often cannot be distinguished before the child is 2 years old.
Prognosis and Treatment
The prognosis usually depends on the type of cerebral palsy and on its severity. Most children with cerebral palsy survive into adulthood. Only the most severely affected—those incapable of any self-care—have a substantially shortened life expectancy.
Cerebral palsy cannot be cured, and its problems are lifelong. However, much can be done to improve a child's mobility and independence. Physical therapy, occupational therapy, and braces may improve muscle control and walking, particularly when rehabilitation is started as early as possible. Surgery may be performed to cut or lengthen tendons of the stiff muscles that limit motion. Sometimes cutting certain nerve roots coming from the spinal cord (dorsal rhizotomy) reduces the spasticity and may help a few children who were premature, as long as spasticity mostly affects the legs and mental development is good. Speech therapy may make speech much clearer and help with swallowing problems. Seizures can be treated with anticonvulsant drugs. Drugs taken by mouth, including baclofen, benzodiazepines (such as diazepam), tizanidine, and sometimes dantrolene, are sometimes used to help spasticity, but their benefits are limited by side effects. Some children with severe spasticity benefit from an implantable pump that provides a continuous infusion of baclofen around the spinal cord, although this technique is still experimental and not widely used. Botulinum toxin can be injected into spastic muscles.
Children with cerebral palsy grow normally and attend regular schools if they do not have severe intellectual and physical disabilities. Other children require extensive physical therapy, need special education, and are severely limited in activities of daily living, requiring some type of lifelong care and assistance. However, even severely affected children can benefit from education and training, which increases their independence and self-esteem and greatly reduces the burden for family members or other caretakers.
Information and counseling are available to parents to help them understand their child's condition and potential and to assist with problems as they arise. Loving parental care combined with assistance from public and private agencies, such as community health agencies, health organizations like the United Cerebral Palsy Association, and vocational rehabilitation organizations, can help children reach their highest potential.
Last full review/revision December 2006 by Hart Peterson, MD
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