Cerebral Palsy

Introduction

Cerebral Palsy (CP) is a movement disorder that results from a non-progressive lesion of motor pathways. Although the lesion does not progress, the symptoms appear gradually, as the child does not develop along normal trends – i.e. it is not noticed at birth as the child is not expected to be able to perform various motor movements, but as the child ages, normal development does not occur, and thus the symptoms become more pronounced.

Although often described as a movement/posture disorder, it is often accompanied by learning difficulties, and other signs of developmental delay

The specific symptoms will depend on where the lesion is. It can affect any part of the brain – e.g. cerebellar disorder, basal ganglia disorder, cerebral etc etc. The distribution of other symptoms is:

• Learning difficulties – 60%
• Epilepsy – 40%
• Squint – 30%
• Visual impairment (any kind) – 20%
• Hearing impairment – 20%
• Speech and language disorders
• Behavioural disorders
• Feeding problems
• Joint disorders
  • Contractures
  • Subluxation
  • Scoliosis

Epidemiology

• 1 in 2000 live births
• The most common cause of motor impairment in childhood.

Aetiology

• Gene deletions
• Antenatal infection
• Vascular occlusion
• Failure of cortical migration
• At birth, screening for haematological disorders may be necessary to exclude an antenatal / post-natal stroke.

10% hypoxic ischaemic birth injury

• Also bear in mind that antenatal disease can result in a difficult birth! Thus it is not always clear what the exact cause is. This can be differentiated with the use of CT scanning to look for cysts – these take 10 days to form – thus if it is truly birth injury, they won’t be present on CT within the first few days of life.

10% post-natal

• Pre-term babies are particularly at risk – as they are more likely to suffer from Periventricular leucomalacia (PVL). This occurs secondary to ischaemia, or haemorrhage.
• Other post-natal causes include:
  • Head injury
  • Meningitis
  • Encephalitis
  • Encephalopathy
  • Hypoglycaemia
  • Hydrocephalus
  • Hyperbilirubinaemia

Presentation

Signs

• ‘Floppy Baby’ – reduced muscle tone in the neonate. This is in contrast to the increased muscle tone seen in older children with CP.
  • Increased muscle tone – seen in older children, consistent with an UMN lesion. Reflexes may be normal/brisk. Always check the tongue for fasciculations!
• Feeding difficulties – due to poor co-ordination. There may be slow feeding, vomiting and gagging.
• Delayed motor milestones
  • Baby may be a late crawler / walker
  • May have an abnormal gait when they do learn to walk
• Asymmetric hand movement – in normal children hand preference is not seen until at least 12 months of age. Hand preference before this age is always pathological.
• Persistence of primitive reflexes – eg. Stepping reflex, Moro etc etc
• Patterns of symptoms – there are four patterns of symptoms that correspond to the type of motor function affected:
  • Spastic – lesion is in the pyramidal or corticospinal tract – 70% of cases.
  • Dystonic – lesion is in the basal ganglia – 10%
  • Ataxic – Cerebellum – 10%
  • Mixed – 10%

Spastic Cerebral Palsy

• Brisk reflexes
• Spasticity
• Extensor plantar response
• May present early, sometimes even as a neonate, after the initial hypotonia subsides

Types of spastic cerebral palsy:

Hemiplegic

• Unilateral – one arm and one leg involved
• Arm usually affected more than leg
• Face unaffected
• Typical presentation – 4-12 months:
  • Closed fist
  • Flexed arm, possibly extended leg
  • Sometimes called the magic carpet sign – when you lift the baby, the legs will be extended at 90’ to the trunk – the baby looks like it is sitting on a magic carpet.
  • Asymmetrical!
• Abnormal gait may be present as the child grows – typically a toe-heel (tip-toe) gait on the affected side.
• Typically not associated with a birth of post-natal injury, although a neonatal stroke might sometimes be the cause.

Quadriplegic

• All four limbs affected
• Usually severe
• Again, arms may be affected more than legs
• Poor head control
• Typically associated with seizures, microcephaly (small head) and moderate to severe intellectual impairment.
• May be a history of hypoxic-ischaemic encephalopathy

Diplegic

• All four limbs are usually affected, but the legs are usually much worse than the arms. Hand function may appear normal.
• Abnormal gait / walking

Ataxic Hypotonic Cerebral Palsy

• Typically symmetrical signs
• Hypotonia, poor balance and delayed motor development
• Unco-ordinated movements
• Tremor
• May be a cerebellar lesion

Dyskinetic Cerebral Palsy

• Dyskinesia – fluctuating muscle tone. This gives rise to involuntary limb movements.
• Due to basal ganglia (or associated extrapyramidal tract) damage
  • in the past was often associated with hyperbilirubinaemia as a result of rhesus disease of the newborn.
• Usually affects all four limbs
• May be especially apparent when stressed
• Types of involuntary movement
  • Chorea – irregular, sudden, solitary
  • Dystonia and athetosis – simultaneous contraction then relaxation of opposing muscle groups.
    • Dystonia – involvement of the trunk and proximal limbs
    • Athetosis – involvement of the distal limbs
• In this type of cerebral palsy, intellectual ability may be unaffected.

Management

• Physiotherapy of affected limbs
• Splinting of affected contractured joints
• Botox injections into affected spastic muscles, to allow the muscle to relax. This is particularly useful for helping gait.
• Speech / language therapy
• In some cases where there is an abnormally early hand preference, the preferred hand may be restricted to encourage movement of the other arm (in the same way children with strabismus use patches to encourage visual development

References

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