eMedicine Specialties > Physical Medicine and Rehabilitation > Medical Diseases

Cerebral Palsy

Author: Christine Thorogood, MD, Associate Professor of Pediatric Physical Medicine and Rehabilitation, Eastern Virginia Medical School
Coauthor(s): Michael A Alexander, MD, FAAPMR, FAAP, Professor, Chief of Division of Rehabilitation Medicine, Departments of Pediatrics and Rehabilitation Medicine, Thomas Jefferson Medical College; Chief of Rehabilitation Medicine, Alfred I duPont Hospital for Children
Contributor Information and Disclosures

Updated: Mar 11, 2009

Introduction

Background

Cerebral palsy is a disorder affecting the development of movement and posture that is believed to arise from nonprogressive disturbances in the developing fetal or infant brain. In addition to the motor disorders that characterize cerebral palsy, which limit a patient's activities, individuals with cerebral palsy often display epilepsy, secondary musculoskeletal problems, and disturbances of sensation, perception, cognition, communication, and behavior.¹

Cerebral palsy has traditionally been classified on the basis of the type of motor disorder that occurs, with variable numbers and descriptions of types.² The revised classification now in use defines 3 main categories of motor disorder, as follows:

• Spastic - 70-80%
• Dyskinetic - 10-15%
• Ataxic - <5%

There are also mixed types.

Spastic cases are further classified according to involvement of the extremities, as follows³ :

• Quadriplegia - 10-15%; all 4 extremities are affected, and the trunk is involved. (See image below and Image 1.)

• Diplegia - 30-40%; the lower extremities are affected more than the upper extremities and in some cases are solely involved. (See image below and Image 2.)
• Hemiplegia - 20-30%; involvement is observed on 1 side of the body, including an arm and a leg, with the arm more involved than the leg. If both arms are more involved than the legs, the condition can be classified as a double hemiplegia.
• Monoplegia - Rare; involvement is noted in 1 limb, either an arm or a leg. If a patient has monoplegia, an effort should be made to rule out causes other than cerebral palsy.

Pathophysiology

Cerebral palsy is caused by an insult to the immature brain; the period during which the insult can occur ranges from any time before birth up to the postnatal period.⁴ (Some classify cerebral palsy as an insult to the brain before age 3 years.) After the immediate postnatal period, cerebral palsy often has an identifiable cause (eg, hypoxic-ischemic encephalopathy), which should be noted. (See image below and Image 3.) The cerebral insult alters muscle tone, muscle stretch reflexes, primitive reflexes, and postural reactions. Other associated symptoms may be involved secondary to the neurologic insult (eg, mental retardation, vision and hearing problems, seizures), but they are not part of the definition of cerebral palsy.

The etiology of the cerebral insults includes vascular, hypoxic-ischemic, metabolic, infectious, toxic, teratogenic, traumatic, and genetic causes. The pathogenesis of cerebral palsy involves multifactorial causes, but much is still unknown. Different pathogenetic mechanisms of cerebral palsy have been associated with preterm and term births. In many cases, a cause cannot be accurately determined. Some believe that a pre-existing condition in some fetuses causes early birth and neurologic problems, as opposed to the prematurity itself causing cerebral palsy.

Frequency

United States

The prevalence of cerebral palsy is approximately 1.5-2 cases per 1000 live births. The incidence of cerebral palsy has not changed in more than 4 decades, despite significant advances in the medical care of neonates.

International

The prevalence of cerebral palsy is approximately 1.5-2 cases per 1000 live births.

Mortality/Morbidity

Cerebral palsy is the leading cause of childhood disability affecting function and development.

Age

The insult that gives rise to cerebral palsy occurs during immature brain development. According to most references, this initiating event can take place anytime between prenatal development and age 3 years. However, children are usually not diagnosed until after age 1 year, with the condition becoming identifiable as children fail to meet developmental milestones. Often, children who are older and are diagnosed as having cerebral palsy — as a result of having presenting symptoms or problems that are similar to those of cerebral palsy — should instead be labeled with the etiology of their brain injury (ie, traumatic brain injury secondary to a motor vehicle accident, stroke, metabolic condition, etc.)

Clinical

History

• The child with cerebral palsy can present after failing to meet expected developmental milestones or failing to suppress obligatory primitive reflexes.
• Abnormal muscle tone is the most frequently observed symptom. The child may present as either hypotonic or, more commonly, hypertonic with either decreased or increased resistance to passive movements, respectively. Children with cerebral palsy may have an early period of hypotonia followed by hypertonia. The longer the period of hypotonia prior to hypertonia, the greater the likelihood that the hypertonia will be more severe.
• Definite hand preference before age 1 year is a red flag for possible hemiplegia.
• Asymmetric crawling or failure to crawl also may suggest cerebral palsy.
• Growth disturbance is often noted in children with cerebral palsy, especially failure to thrive.

Physical

• Joint contractures secondary to spastic muscles
• Hypotonic to spastic tone
• Growth delay
• Persistent primitive reflexes - Examples such as the Moro, asymmetric tonic neck, symmetric tonic neck, palmar grasp, tonic labyrinthine, and foot placement reflexes are noted. The Moro and tonic labyrinthine reflexes should extinguish by the time the infant is aged 4-6 months; the palmar grasp reflex, by 5-6 months; the asymmetric and symmetric tonic neck reflexes, by 6-7 months; and the foot placement reflex, before 12 months.
• The overall gait pattern should be observed and each joint in the lower extremity and upper extremity should be assessed.
  • Hip - Excessive flexion, adduction, and femoral anteversion make up the predominant motor pattern. Scissoring of the legs is common in spastic cerebral palsy.
  • Knee - Flexion and extension with valgus or varus stress occur.
  • Foot - Equinus, or toe walking, and varus or valgus of the hindfoot is common in cerebral palsy.
• Gait abnormalities may include the crouch position with tight hip flexors and hamstrings, weak quadriceps, and/or excessive dorsiflexion.
• Physical attributes of different types of cerebral palsy
  • The spastic type (pyramidal cerebral palsy) constitutes 75% of patients with cerebral palsy. Patients have signs of upper motor neuron involvement, including hyperreflexia, clonus, extensor Babinski response, persistent primitive reflexes, and overflow reflexes (crossed adductor). Cognitive impairment is present in approximately 30% of spastic diplegic patients, but most patients with spastic quadriplegia have some cognitive impairment.
  • The dyskinetic type (extrapyramidal cerebral palsy) is characterized by extrapyramidal movement patterns, abnormal regulation of tone, abnormal postural control, and coordination deficits. Athetosis, chorea, and choreoathetoid or dystonic movements can be seen. Patients often have pseudobulbar involvement, with dysarthria, swallowing difficulties, drooling, oromotor difficulties, and abnormal speech patterns. Generally, patients are hypotonic at birth, with abnormal movement patterns emerging at 1-3 years. The arms are usually more involved than the legs. Abnormal movement patterns may increase with stress or purposeful activity. Muscle tone is usually normal during sleep. Intelligence is normal in 78% of patients with athetoid cerebral palsy. A high incidence of sensorineural hearing loss is reported.
  • Patients with spastic diplegia often have a period of hypotonia followed by extensor spasticity in the lower extremities, with little or no functional limitation of the upper extremities. Patients have a delay in developing gross motor skills. Spastic muscle imbalance often causes persistence of infantile coxa valga and femoral anteversion. A scissoring gait (ie, hips flexed and adducted, knees flexed with valgus stress, equinus ankles) is observed.
  • Hemiplegia is characterized by weak hip flexion and ankle dorsiflexion, an overactive posterior tibialis muscle, hip hiking/circumduction, supinated foot in stance, upper extremity posturing (that is, often held with the shoulder adducted, elbow flexed, forearm pronated, wrist flexed, hand clenched in a fist with the thumb in the palm), impaired sensation, impaired 2-point discrimination, and/or impaired position sense. Some cognitive impairment is found in about 28% of these patients.

Related eMedicine topics:
Spasticity [Neurology]
Spasticity [Physical Medicine and Rehabilitation]

Causes

• Prenatal
  • Intrauterine infections⁵
  • Congenital malformations
  • Toxic or teratogenic agents
  • Multiple births
  • Abdominal trauma
  • Maternal illness
• Neonatal
  • Prematurity (less than 32 weeks' gestation)
  • Birthweight less than 2500 g
  • Growth retardation
  • Intracranial hemorrhage
  • Trauma
  • Infection
  • Bradycardia and hypoxia
  • Seizures
  • Hyperbilirubinemia
  • Abnormal birthing presentations
• Postnatal
  • Trauma
  • Infection
  • Intracranial hemorrhage
  • Coagulopathies

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