Cerebral Palsy

Introduction

Cerebral palsy is not a single disease but a description: a group of permanent disorders of the development of movement and posture, causing activity limitation, attributed to non-progressive disturbances occurring in the developing fetal or infant brain.⁴ The motor disorder is commonly accompanied by disturbances of sensation, perception, cognition, communication and behaviour, by epilepsy, and by secondary musculoskeletal problems.

Three words in that definition do the work. Permanent - the brain injury does not recover. Non-progressive - the lesion itself does not worsen, which is what distinguishes cerebral palsy from a neurodegenerative disorder. Developing - the insult occurs to an immature brain, conventionally taken as up to about 2 years of age.

The apparent paradox students find confusing is that a static lesion produces a changing clinical picture. As a child grows, muscle fails to lengthen at the same rate as bone, fixed contractures develop, hips migrate out of their sockets and scoliosis appears. The brain lesion is unchanged; the consequences are not. This is why cerebral palsy is managed as an active, lifelong surveillance problem rather than a diagnosis to be made once and then filed away.¹

Aetiology

NICE NG62 groups causes by timing, and it is worth knowing that the majority are antenatal - a corrective to the widespread assumption that cerebral palsy is usually the result of something that went wrong during labour.¹

Risk factors

• Preterm birth - the largest single risk factor, with risk rising steeply as gestation falls. Periventricular leukomalacia is the classic lesion, producing spastic diplegia.
• Low birth weight and intrauterine growth restriction
• Multiple pregnancy
• Chorioamnionitis and maternal infection
• Hypoxic-ischaemic encephalopathy, particularly grade 2 or 3
• Neonatal encephalopathy, seizures, hypoglycaemia and kernicterus
• Male sex, which carries a modestly higher risk

Classification

By motor type

By distribution of spasticity

• Hemiplegia - one side of the body, with the arm more affected than the leg. Usually a unilateral lesion such as a perinatal middle cerebral artery stroke. Presents with early hand preference and a fisted hand.
• Diplegia - legs more affected than arms. The classic pattern following periventricular leukomalacia in a preterm infant, because the corticospinal fibres to the legs run closest to the ventricles. Produces scissoring, toe-walking and tiptoe posturing.
• Quadriplegia (tetraplegia) - all four limbs, trunk and bulbar muscles. The most severe form, usually following extensive hypoxic-ischaemic injury, and strongly associated with epilepsy, learning disability, microcephaly and swallowing difficulty.
• Monoplegia - a single limb, uncommon

By function - the GMFCS

The Gross Motor Function Classification System describes what a child actually does in daily life. It is more useful than the anatomical label because it predicts prognosis, guides intervention and is broadly stable after about the age of 5.

Clinical features and early recognition

Cerebral palsy is rarely diagnosed at birth. It declares itself over the first two years as motor milestones are missed and abnormal tone and posture emerge. NICE lists specific features that should prompt urgent referral to a child development service.¹

Motor red flags

• Not sitting by 8 months corrected age
• Not walking by 18 months corrected age
• Hand preference before 12 months - a normal infant uses both hands, so early handedness suggests a weak contralateral side and is one of the most useful single signs
• Persistent toe-walking
• Asymmetry of movement or posture
• Delayed or absent postural reactions, and persistence of primitive reflexes such as the Moro or asymmetric tonic neck reflex beyond 6 months

Other early features

• Abnormal tone - infants are often hypotonic early and develop hypertonia over the following months, which is why an initially floppy baby can end up spastic
• Fisting of the hands beyond 3 months, and scissoring of the legs when held vertically
• Feeding difficulties - poor suck, prolonged feeds, coughing during feeds, and faltering growth
• Excessive irritability, poor sleep and a persistent high-pitched cry
• Delayed or absent smiling and poor visual attention
• Head lag persisting beyond 4-6 months

Associated problems

These are examined at least as often as the motor features, and in practice they cause more of the day-to-day burden. NICE emphasises that several - particularly pain - are systematically under-recognised in children who cannot easily report them.¹

Investigations

The diagnosis is clinical. Investigations identify the underlying lesion, exclude mimics and characterise the associated problems - but the diagnosis should not be delayed while waiting for imaging.

• MRI brain - identifies an abnormality in around 85-90% of cases and helps establish the timing and nature of the insult. NICE recommends it where the cause is not already clear from the history.
• Genetic and metabolic testing - indicated if the MRI is normal, if the clinical features are atypical, if there is a family history, or if there is any suggestion of regression
• EEG if seizures are suspected, alongside the epilepsy pathway⁵
• Formal vision and hearing assessment in every child, since sensory impairment is common and compounds every other difficulty
• Hip radiographs as part of a structured hip surveillance programme, with frequency determined by GMFCS level - this is a specific, examinable point
• Videofluoroscopic swallow study where aspiration is suspected
• Bone health assessment - vitamin D, calcium and, where there have been fragility fractures, bone densitometry

Management

Management is multidisciplinary, lifelong, and organised around the child's and family's own goals rather than around normalising gait. The team typically includes a paediatrician, physiotherapist, occupational therapist, speech and language therapist, dietitian, orthotist, specialist nurse, psychologist, orthopaedic surgeon, and education and social care colleagues.

Managing spasticity

• Physiotherapy and a stretching programme, with 24-hour postural management including seating, sleeping and standing positions
• Orthoses, particularly ankle-foot orthoses, to maintain range and improve gait
• Oral baclofen for generalised spasticity; oral diazepam short-term for painful spasm
• Botulinum toxin A injections for focal spasticity interfering with function, always combined with physiotherapy and orthoses afterwards
• Intrathecal baclofen by implanted pump for severe generalised spasticity
• Selective dorsal rhizotomy, in carefully selected children with spastic diplegia at GMFCS levels II-III, followed by an intensive rehabilitation programme

Managing dystonia

• A trial of levodopa - both as treatment and to exclude dopa-responsive dystonia
• Trihexyphenidyl, and intrathecal baclofen for severe generalised dystonia
• Deep brain stimulation in selected children at specialist centres
• Treat triggers - pain, infection, constipation and anxiety all worsen dystonia, and a dystonic crisis is a medical emergency requiring hydration, sedation and treatment of the precipitant

Orthopaedic and musculoskeletal care

• Hip surveillance with regular clinical and radiographic review, since progressive hip migration is silent, painful once dislocated and largely preventable
• Soft tissue surgery such as adductor release, and bony surgery including femoral and pelvic osteotomy
• Scoliosis monitoring and surgery, particularly in GMFCS IV-V
• Bone health - vitamin D and calcium, weight-bearing where possible, and bisphosphonates for recurrent fragility fractures

Feeding, growth and general health

• Speech and language therapy swallow assessment, with modified textures and positioning
• Gastrostomy feeding where oral intake is unsafe or inadequate - a decision made with the family, and one that usually improves both nutrition and quality of life
• Active treatment of constipation and reflux, both of which are ubiquitous and both of which cause pain
• Drooling - positioning and oromotor therapy first, then anticholinergics such as glycopyrronium or hyoscine patches, and botulinum toxin to the salivary glands
• Immunisations kept up to date, including annual influenza vaccination, given the aspiration risk
• Communication aids and educational support, with an Education, Health and Care plan where appropriate

Prognosis

Prognosis is best predicted by GMFCS level and by the presence of associated impairments, particularly epilepsy, learning disability and swallowing difficulty. A useful rule for families is that a child who can sit independently by the age of 2 will very probably walk, whereas one who cannot sit by 4 is unlikely to.

Life expectancy at GMFCS levels I and II approaches that of the general population, and most of these young people live independently, work and have families. At GMFCS level V, particularly where there is an unsafe swallow, uncontrolled epilepsy and recurrent aspiration, life expectancy is substantially reduced, and respiratory disease is the leading cause of death.³

It bears repeating that the brain lesion does not progress. What changes is the musculoskeletal consequence of growing with abnormal tone, and much of that is preventable or at least modifiable with hip surveillance, postural management, spasticity treatment and good nutrition - which is precisely why the surveillance framework matters more than any single intervention.

Finally, outcome should be judged in terms the family recognises. Improvements in communication, comfort, seating, sleep and participation in school and social life often matter far more to a child and their parents than a change in gait pattern, and NICE's emphasis on goal-setting with the family rather than for them reflects that.