Cerebral palsy

Definition
Cerebral palsy is a group of disorders characterized by loss of movement or loss of other nerve functions. These disorders are caused by injuries to the brain that occur during fetal development or near the time of birth.

Causes, incidence, and risk factors

Cerebral palsy is caused by injury to the cerebrum (the largest portion of the brain, which is involved with higher mental faculties, sensations, and voluntary muscle activities).

Initially cerebral palsy was thought to be related to birth asphyxia (strangulation during birth, which leads to lack of oxygen to the brain) and trauma, but in a study of 45,000 births it was shown that birth asphyxia is an uncommon cause of cerebral palsy. Affected brain areas receive lower levels of oxygen (hypoxia) at some point, but it is not known why this occurs.

Researchers suspect that certain factors or events during the development of the fetus may make it more susceptible to any hypoxia that occurs, and this may be why some infants are affected while others can suffer low oxygen levels but not lasting brain damage.

Premature infants have a slightly higher incidence of cerebral palsy. Cerebral palsy may also occur during early infancy as a result of illnesses (encephalitis, meningitis, herpes simplex infections, and so on), Head injury that results in subdural hematoma, blood vessel injuries, and many others.

Injury to the cerebrum can result in the loss of nerve functions in widely different areas. The classical finding of CP is spasticity (increased muscle tone) which may affect a single limb, one side of the body (spastic hemiplegia), both legs (spastic diplegia) or both arms and legs (spastic quadriplegia). In addition, there may be partial or full loss of movement (paralysis), sensory abnormalities, and defects of hearing and vision. Speech abnormalities are common and seizures may occur.

Intellectual function may range from extremely bright normal to severe mental retardation. Symptoms are usually evident before age 2 and in severe cases may appear as early as 3 months. Cerebral palsy is a non-progressive type of encephalopathy (injury to the brain) and symptoms directly resulting from the disease do not worsen.

Classifications of cerebral palsy include spastic, dyskinetic, ataxic, and mixed. Spastic cerebral palsy includes about 50% of cases. Dyskinetic (athetoid) cerebral palsy affects about 20%. It involves development of abnormal movements (twisting, jerking, or other movements). Ataxic cerebral palsy involves tremors, unsteady gait, loss of coordination, and abnormal movements. It affects about 10%. The remaining 20% are classified as mixed, with any combination of the above symptoms.

Symptoms

     
  • seizures  
  • muscle contractions  
  • difficulty sucking or feeding  
  • irregular breathing  
  • delayed development of motor skills, such as reaching, sitting, rolling, crawling, walking, and so on  
  • motormental retardation  
  • mental retardation  
  • speech abnormalities (dysarthria)  
  • visual abnormalities  
  • hearing abnormalities  
  • spasticity  
  • progressive joint contractures  
  • limited range of motion  
  • peg teeth

Signs and tests
In many cases, a doctor’s examination indicates delayed development of motor skills. Infantile reflexes (such as sucking and startle) may persist past the age where they usually disappear. Muscle tremor or spasticity may be evident, with a tendency of infants to tuck their arms in toward their sides, scissors movements of the legs, or other abnormal movements.

Various laboratory tests may be performed to eliminate nutritional or other causes of the symptoms.

     
  • MRI of the head demonstrates structural or congenital abnormalities  
  • CT scan of the head demonstrates structural or congenital abnormalities  
  • Hearing screen (to determine auditory status)  
  • Visual testing (to determine visual status)  
  • EEG  
  • Blood tests to exclude metabolic or hereditary conditions

Treatment
There is no specific cure for cerebral palsy. The goal of treatment is to maximize independence. Treatment is guided by the symptoms exhibited and may include physical therapy, braces, appropriate glasses and hearing aids, medications, special education or appropriate schooling, and, in severe cases, institutionalization.

Mainstreaming in regular schools is advised unless physical disabilities or mental development makes this impossible. Glasses, hearing aids, or other equipment must be designed specifically for the particular disabilities and may assist with communication and learning. Physical therapy, occupational therapy, orthopedic intervention, or other treatments may be appropriate.

Medications may include muscle relaxants to reduce tremors and spasticity, and anticonvulsants to prevent or reduce the frequency of seizures.

Surgery may be needed in some cases to release joint contractures, a progressive problem associated with spasticity. Surgery may also be necessary for placement of feeding tubes and to control gastroesophageal reflux. Recently, the use of botulinum toxin injections has been show to reduce or delay the need for surgery.

Support Groups

For organizations that provide support and additional information, see cerebral palsy resources.

Expectations (prognosis)
Cerebral palsy is a lifelong disorder. Long-term care may be required. The disorder does not affect expected length of life. The extent of disability varies.

Complications

     
  • seizures  
  • injuries from falls  
  • reduced mobility  
  • reduced communication skills (sometimes)  
  • reduced intellect (sometimes)  
  • social stigmatization

Calling your health care provider
Call your health care provider if symptoms of cerebral palsy develop, especially if you know that an injury occurred during birth or early infancy.

Prevention

Adequate prenatal care may reduce the risk of some rare causes of cerebral palsy. However, dramatic improvements over the last 15 years in obstetrical care at delivery has not reduced the incidence of cerebral palsy. In most cases, the injury causing the disorder may not be preventable.

Pregnant mothers with various medical conditions may need to be followed in a high risk prenatal clinic.

Johns Hopkins patient information

Last revised: December 3, 2012
by Gevorg A. Poghosian, Ph.D.

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