Cerebral palsy can be defined as "a persistent (but not unchanging) disorder of movement and posture, as the result of one or more non-progressive abnormalities in the brain, before its growth and development are complete. Other clinical signs may be present as well."
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. In many cases, no cause can be identified.
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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
Classification based on aetiology
Classification can be according 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 (= t oxoplasmosis, o ther, r ubella, c ytomegalovirus, h erpes 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 of 2.0 per 1,000 live births for birth years 1986-1996.
The prevalence of cerebral palsy in very low-birthweight infants and those born at less than 32 weeks of gestation has been shown to have decreased significantly from 6% of livebirths (60.6 per 1,000) in 1980 to 4% (39.5 per 1,000) in 1996.
Where type is recorded, 91% had spastic cerebral palsy. Where data are available, nearly one-third of children had severely impaired lower limb function and nearly a quarter had severely impaired upper limb function.
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. 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.
The list of differential diagnoses may be wide-ranging. The following are commonly considered in the differential diagnosis of cerebral palsy:
- Acute poliomyelitis.
- Becker's muscular dystrophy (a group of genetic diseases causing muscle weakness - affects only males).
- Charcot-Marie-Tooth syndrome.
- 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 type of investigations will depend upon the presentation and the list of differential diagnoses that need to be excluded.
- Thyroid studies.
- Chromosomal analysis.
- Lactate and pyruvate 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 organic acid and amino acid conditions 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.
Although there are no definitive diagnostic tests, neuroimaging can help to identify patients who are likely to be at risk.
- Ultrasound can help to identify very preterm babies at risk of cerebral palsy. One study found a strong link between severe cranial abnormalities identified in the neonatal period and the incidence of cerebral palsy 2 years later, although one third of children with cerebral palsy had no detectable ultrasound abnormalities.
- MRI scans are useful for detecting white matter lesions in older children, but traditional methods used in younger children have failed to provide good predictive results. However, newer developments and the use of sequential MRI have proven of value in demonstrating the various injuries (eg asphyxia) and anomalies that can lead to cerebral palsy. Fetal MRI has also yielded useful information.
- CT scanning may provide information about structural congenital malformations and vascular abnormalities and haemorrhages, especially in babies.
- 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.
- 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 recent study found that cerebral malformations were much more frequent among children with cerebral palsy than among all livebirths 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 birthweight).
- Maternal abdominal trauma - very rare unless there is extensive injury causing coexistent fetal brain trauma.
- Maternal illness - eg intrauterine infections, thyroid abnormalities and any condition leading to low birthweight.
- 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 involve 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 can have severe consequences, eg seizures, hyperthermia, rhabdomyolysis and multiorgan failure.
- Dantrolene may work better than baclofen when muscle spasm is severe.
- Diazepam is another option for severe muscle spasm.
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.
- Botulinum toxin - this can afford the relief of spasticity for 3-6 months.
- Phenol injections - sometimes used in larger muscles, where botulinus would be ineffective.
- 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.
- 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 two year-old 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, mental retardation and medical complications such as reflux and pulmonary disease.
Studies suggest that, if a child can sit up unaided at the age of 2, they will eventually be able to walk. If they are unable to sit by the age of 4, they will be unable to walk.
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.
- Modern obstetric techniques to reduce birth trauma.
Proactive treatment to minimise the effects of perinatal brain injury (including magnesium sulphate in the preterm newborn and hypothermia in the term newborn) is currently being investigated.
Many cases of cerebral palsy are still unexplained, however, and further work needs to be done on the aetiology of perinatal brain injury.
Further reading & references
- Cerebral Palsy, National Institute of Neurological Disorders and Stroke
- Griffiths M, Clegg M (eds); Cerebral Palsy: Problems and Practice. Human Horizons Series
- Jan MM; Cerebral palsy: comprehensive review and update. Ann Saudi Med. 2006 Mar-Apr;26(2):123-32.
- Rosenbaum P; Cerebral palsy: what parents and doctors want to know. BMJ. 2003 May 3;326(7396):970-4.
- Palisano R, Rosenbaum P, Walter S, et al; Development and reliability of a system to classify gross motor function in children with cerebral palsy. Dev Med Child Neurol. 1997 Apr;39(4):214-23.
- Hanna SE, Bartlett DJ, Rivard LM, et al; Reference curves for the Gross Motor Function Measure: percentiles for clinical Phys Ther. 2008 May;88(5):596-607. Epub 2008 Mar 13.
- Surman G, Bonellie S, Chalmers J, et al; UKCP: a collaborative network of cerebral palsy registers in the United Kingdom. J Public Health (Oxf). 2006 Jun;28(2):148-56. Epub 2006 Mar 23.
- Platt MJ, Cans C, Johnson A, et al; Trends in cerebral palsy among infants of very low birthweight (<1500 g)="" or="" born="" lancet.="" 2007="" jan="">1500>
- Wu YW, Croen LA, Shah SJ, et al; Cerebral palsy in a term population: risk factors and neuroimaging findings. Pediatrics. 2006 Aug;118(2):690-7.
- Lie KK, Groholt EK, Eskild A; Association of cerebral palsy with Apgar score in low and normal birthweight BMJ. 2010 Oct 6;341:c4990. doi: 10.1136/bmj.c4990.
- Thorogood C et al, Physical Medicine and Rehabilitation for Cerebral Palsy, Medscape, Mar 2011
- Bushby K; Becker muscular dystrophy factsheet. Muscular Dystrophy Campaign
- Oleszek JL et al, Kugelberg Welander Spinal Muscular Atrophy, Medscape, Jul 2008
- Chuang DT, Chuang JL, Wynn RM; Lessons from genetic disorders of branched-chain amino acid metabolism. J Nutr. 2006 Jan;136(1 Suppl):243S-9S.
- Ancel PY, Livinec F, Larroque B, et al; Cerebral palsy among very preterm children in relation to gestational age and neonatal ultrasound abnormalities: the EPIPAGE cohort study. Pediatrics. 2006 Mar;117(3):828-35.
- Dyet LE, Kennea N, Counsell SJ, et al; Natural history of brain lesions in extremely preterm infants studied with serial magnetic resonance imaging from birth and neurodevelopmental assessment. Pediatrics. 2006 Aug;118(2):536-48.
- Zimmerman RA, Bilaniuk LT; Neuroimaging evaluation of cerebral palsy. Clin Perinatol. 2006 Jun;33(2):517-44.
- Leggatt A et al, Somatosensory Evoked Potentials, General Principles, Medscape, Sep 2009
- Abdel-Hamid HZ et al, Cerebral Palsy, Medscape, Dec 2011
- Bodensteiner JB, Johnsen SD; Magnetic resonance imaging (MRI) findings in children surviving extremely premature delivery and extremely low birthweight with cerebral palsy. J Child Neurol. 2006 Sep;21(9):743-7.
- Garne E, Dolk H, Krageloh-Mann I, et al; Cerebral palsy and congenital malformations. Eur J Paediatr Neurol. 2008 Mar;12(2):82-8. Epub 2007 Sep 19.
- Selective dorsal rhizotomy for spasticity in cerebral palsy, NICE Interventional Procedure Guideline (December 2010)
- Manley MT, Gurtowski J; The vertical wheeler: a device for ambulation in cerebral palsy. Arch Phys Med Rehabil. 1985 Oct;66(10):717-20.
- Duncan B, McDonough-Means S, Worden K, et al; Effectiveness of osteopathy in the cranial field and myofascial release versus acupuncture as complementary treatment for children with spastic cerebral palsy: a pilot study. J Am Osteopath Assoc. 2008 Oct;108(10):559-70.
- Hutton JL; Cerebral palsy life expectancy. Clin Perinatol. 2006 Jun;33(2):545-55.
- du Plessis AJ, Volpe JJ; Perinatal brain injury in the preterm and term newborn. Curr Opin Neurol. 2002 Apr;15(2):151-7.
|Original Author: Dr Laurence Knott||Current Version: Dr Hayley Willacy|
|Last Checked: 22/06/2011||Document ID: 1657 Version: 24||© EMIS|
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