Professional Reference articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Several attempts have been made to construct an all-encompassing definition of the multi-faceted condition that is cerebral palsy. The Study of Cerebral Palsy in Europe (SCPE) and the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) have attempted a unifying definition, as follows: "Cerebral palsy describes a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing foetal or infant brain. The motor disorders are often accompanied by disturbances of sensation, perception, cognition, communication and behaviour; by epilepsy and by secondary musculoskeletal problems."
The basic aetiology is damage to the immature brain. Most authorities agree this damage occurs up to the postnatal period but some classify cerebral palsy as damage occurring before the age of 3 years.
The damage may be vascular, hypoxic-ischaemic, teratogenic, genetic or due to infection, toxins, metabolic problems or trauma. Disruption in blood flow in areas of the brain poorly served by the cerebral circulation is often considered to be the cause. Prenatal, perinatal and postnatal circulatory dysfunction leads to different physical impairments and thus different clinical patterns.However, there is still much to learn. In a study from Denmark, a cause could be found in only one third of cases.
Classification based on type of movement disorder
- Spastic type - there may be intermittent increased tone and pathological reflexes.
- Athetoid - this is characterised by increased activity (hyperkinesia). This has been described as 'stormy movement'.
- Ataxic type - there may be loss of orderly muscular co-ordination so that movements are performed with abnormal force, rhythm or accuracy.
- Mixed - there may be a combination of several forms.
Classification based on distribution of motor involvement
Motor deficits include:
- Double hemiplegia
The severity of gross motor impairment is quantified using the Gross Motor Function Classification System. This facilitates initial assessment and monitoring response to therapy. A Manual Ability Classification System based on the patient's competence in performing manual tasks has also been developed
Classification based on aetiology
Classification can be according to the timing of the insult as prenatal (the most common), natal, or postnatal. Alternatively, it may depend on the actual cause, such as congenital (developmental, malformations, syndromic) or acquired (traumatic, infectious, hypoxic, ischaemic, TORCH (= Toxoplasmosis, Other, Rubella, Cytomegalovirus, Herpes simplex) infections and others).
Cerebral palsy is a relatively rare condition. Pooled data from five active cerebral palsy registers in the UK suggest a mean annual prevalence rate for normal birth-weight children of 1.2 per 1,000 live births. The rate amongst children with birth weights <2500 g was significantly higher at 16 per 1,000 live births
Paradoxically, among the infants who were very severely impaired, those born much lighter than average for gestational age had the longest life expectancy. Those born much heavier than average for gestational age had the shortest life expectancy.
Th UK pooled data set showed that the severity of impairment increased with increasing gestational age at birth in bilateral spastic cerebral palsy but severity did not vary with gestational age in unilateral palsy. This suggests a different aetiology for the two conditions.
The incidence is higher in premature infants and twin births.
Other risk factors include:
- Maternal age greater than 35 years.
- Black ethnicity.
- Intrauterine growth restriction.
Cerebral palsy is strongly associated with a low Apgar score 5 minutes after birth.However, the majority of babies with low scores DO NOT develop cerebral palsy.
It may be suspected when developmental milestones are delayed. A definitive diagnosis may be difficult until specific signs of cerebral palsy appear and this may not happen until the child is 12-18 months old.
Abnormalities of posture and movement are common throughout the different types of cerebral palsy.
The prevalence of the different types of motor disability has remained remarkably constant over the period of 20 years:Bilateral spastic cerebral palsy is the most prevalent, followed by unilateral or hemiplegic cerebral palsy. Bilateral dystonic cerebral palsy is the least common.
Other commonly associated symptoms are:
- Epilepsy: up to 36% of children with cerebral palsy will have onset of seizures within the first year of life.
- Feeding and nutrition: failure to thrive and malnourishment are common secondary to pseudobulbar palsy.
- Bladder problems: incontinence and infections are common.
- Bowel problems: constipation is common and results from a combination of poor mobility and poor oral intake.
- Sleep disturbances: for example, fragmented sleep, which can occur in up to 50% of children.
- Drooling: this may also result from pseudobulbar palsy.
- Orthopaedic problems: for example, progressive joint contractures, shortened muscles, hip or foot deformities, scoliosis and fractures due to osteomalacia or osteoporosis, which are more common with increasing motor disability.
- Non-motor problems:
- Sensation and perception (tactile, vision, hearing).
- Cognition (some relation to physical severity).
The list of differential diagnoses may be wide-ranging. Because the diagnosis is mainly clinical, it is important to observe the child on several occasions. Some authorities suggest deferring the diagnosis until the patient is 1-2 years old to exclude short-term conditions such as transient hypotonia.The following are commonly considered in the differential diagnosis of cerebral palsy:[11, 12]
- Acute poliomyelitis.
- Becker's muscular dystrophy (a group of genetic diseases causing muscle weakness - affects only males).
- Charcot-Marie-Tooth disease.
- Kugelberg-Welander spinal muscular atrophy - a rare inherited disorder causing progressive degeneration of the anterior horn cells of the spinal cord.
- Neonatal brachial plexus palsies.
- Stroke motor impairment.
- Traumatic brain injury.
The diagnosis of cerebral palsy is based on clinical examination and parental observation. However, investigations occasionally required to exclude other diagnoses might include:
- Thyroid studies.
- Chromosomal analysis.
- Pyruvate and lactate levels to exclude mitochondrial cytopathies (a group of systemic diseases caused by inherited or acquired damage to the mitochondria).
- Organic and amino acid levels to exclude inborn errors of metabolism presenting with neurological symptoms.
- Cerebrospinal fluid - protein, lactate and pyruvate levels may be helpful in determining whether there has been any asphyxia in the neonatal period.
There has been controversy over the use of neuroimaging in the prediction of cerebral palsy in neonates. However, studies have determined that:
- Sequential ultrasound imaging can detect major intracranial lesions in patients who subsequently develop non-ambulatory cerebral palsy.
- MRI can refine the prediction of cerebral palsy by assessing myelination of the posterior limb of the internal capsule.
- Diffusion-weighted imaging can improve prediction further.
- Fetal MRI has also yielded useful information.
- CT scanning may provide information about structural congenital malformations and vascular abnormalities and haemorrhages, especially in babies.
- Positron emission tomography (PET) scanning is a further enhancement which exposes the patient to less radiation than CT.
- Evoked potentials - these are the electrical signals produced by the nervous system in response to sensory stimuli. Measuring them can help to detect abnormalities of hearing and vision.
- Electroencephalogram (EEG) - this can help to detect damage from hypoxia and vascular insult.
- Intrauterine infections - eg, rubella, HIV, cytomegalovirus, toxoplasmosis.
- Congenital malformations - this is often due to intrauterine events such as vascular insult and particularly affects the cerebellum, periventricular regions and corpus callosum.A study found that cerebral malformations were much more frequent among children with cerebral palsy than among all live births in the population. The study also found an increase in non-cerebral malformations close to the brain (eg, eye, facial clefts) in such children.
- Toxic or teratogenic agents - including alcohol, cocaine and cigarette smoke (probably relates to low birth weight).
- Maternal abdominal trauma - very rare unless there is extensive injury causing co-existent fetal brain trauma.
- Maternal illness - eg, thyroid abnormalities and any condition leading to low birth weight.
- Intracranial haemorrhage.
- Maternal iodine deficiency.
The treatment of cerebral palsy needs to be multidisciplinary and goal-directed. There is a danger that various abnormalities (eg, movement disorder) could be treated in a disjointed fashion without any overall view of the benefits to the patient and the family.
Many disciplines will need to be involved and treatment will often entail input from:
- Occupational therapists
- Speech therapists
- Recreational therapists
- Baclofen is helpful in relieving muscle spasm. It is usually given orally but can be administered in the form of an intrathecal cannula and pump in cases of diffuse spasticity.Withdrawal syndrome occurs particularly with the intrathecal route and can have severe consequences - eg, seizures, hyperthermia, rhabdomyolysis and multiorgan failure.
- Other first-line options of proven effectiveness include tizanidine and botulinum toxin A.
- Second-line options which have demonstrated variable effectiveness include diazepam, dantrolene and gabapentin.
Orthopaedic procedures are usually a last resort for children with severe spasticity and/or fixed contractures/deformities:
- Repair of scoliosis and hip dislocation.
- Tendon lengthening or transfer to decrease the imbalance from muscle spasticity.
- Osteotomy to realign a limb.
- Selective posterior rhizotomy - this involves operating on nerve roots emanating from the spinal cord and is useful in selected patients with muscle spasticity.There is a risk of serious but well-recognised complications. It is used less often now that the baclofen infusion pump is available.
- Mobility aids - these may include orthotic devices, wheelchairs and powered mobility walkers.
- Phenol injections are sometimes used in larger muscles, where botulinum toxin A would be ineffective. However, studies suggest that in most other cases the latter is more effective.
- Deep brain stimulation has proved to be beneficial in young people with severe dystonic quadriplegic cerebral palsy.
- Stem cell therapy has been supported by anecdotal evidence but controlled trials are needed.
- Physical methods of spasticity relief include heat, cold and vibration.
- There is some evidence that cranial osteopathy and myofascial release can improve mobility in patients with moderate-to-severe cerebral palsy.
- Splinting can help to improve the range of movement of a joint; this can be particularly effective for ankle joints.
- Complementary therapies are widely offered but there is very little evidence of effectiveness in the scientific literature.
- The psychological and physical health of carers should not be forgotten.
- With improved care, the life expectancy of cerebral palsy patients is lengthening. The social and educational integration of young adults into the community is a matter of increasing importance.
- Gastrointestinal symptoms and their sequelae - eg, reflux, oropharyngeal muscle disorders, failure to thrive and osteoporosis.
- Pulmonary complications - eg, aspiration pneumonia and bronchopulmonary dysplasia.
- Dental problems.
- Moderate/severe learning difficulties (in 30-50% of patients associated with severe spastic quadriplegia).
- Hearing loss (particularly seen where the secondary cause is hyperbilirubinaemia or exposure to ototoxic drugs).
Many patients with a mild form have a normal life expectancy. A child aged 2 years with mild palsy has a 99% chance of living to the age of 20, compared with a patient who has severe disease, where the figure can be as low as 40%.A poor prognosis is associated with severe quadriplegia, epilepsy and general learning disability. The introduction of tube feeding has reduced the incidence of oesophageal reflux and pneumonia but has had more of an impact on prognosis in children than in adults.
Studies suggest that a child able to sit up unaided and pull to a standing position at the age of 2 years will eventually achieve successful ambulation.
Much has been done to reduce the incidence of cerebral palsy, including:
- The recognition and treatment of maternal iodine deficiency.
- The prevention of kernicterus associated with rhesus isoimmunisation.
- Techniques to reduce the rate of preterm births - eg:
- Limiting the number of embryos transferred with in vitro fertilisation.
- Smoking cessation during pregnancy.
- Screening for and treatment of asymptomatic bacteriuria during pregnancy.
- Antiplatelet drugs to prevent pre-eclampsia.
- 17α-progesterone caproate and cervical cerclage for women with previous preterm birth and short cervix.
- Treatments to prolong pregnancy in preterm labour - eg:
- Calcium-channel blockers
- Oxytocin antagonist (atosiban) for women with preterm labour.
- Erythromycin for women with premature rupture of the membrane.
There is insufficient evidence to recommend the routine administration of magnesium sulfate to women at term for the neuroprotection of the newborn fetus.
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Further reading & references
- Cerebral palsy in under 25s: assessment and management; NICE Guidance (January 2017)
- Jackman M, Novak I, Lannin N; Effectiveness of functional hand splinting and the cognitive orientation to occupational performance (CO-OP) approach in children with cerebral palsy and brain injury: two randomised controlled trial protocols. BMC Neurol. 2014 Jul 15 14:144. doi: 10.1186/1471-2377-14-144.
- McMichael G, Girirajan S, Moreno-De-Luca A, et al; Rare copy number variation in cerebral palsy. Eur J Hum Genet. 2014 Jan 22(1):40-5. doi: 10.1038/ejhg.2013.93. Epub 2013 May 22.
- Jensen A; Autologous cord blood therapy for infantile cerebral palsy: from bench to bedside. Obstet Gynecol Int. 2014 2014:976321. doi: 10.1155/2014/976321. Epub 2014 Feb 20.
- Cerebral Palsy; National Institute of Neurological Disorders and Stroke
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