Cerebral palsy - Hereditary and congenital disorders

Hereditary and congenital disorders

Cerebral palsy

Definition

Cerebral palsy (CP) is a heterogeneous group of conditions arising from a non-progressive lesion occurring in the developing brain. Although the lesion is non-progressive, the brain is still maturing and the clinical picture is therefore not static.

Incidence

3 per 1000 live births.

Aetiology

The precise cause of the damage may be difficult to identify and is often multifactorial. About 10–15% acquire the lesion at birth, and a similar proportion occur after the neonatal period. Most occur prenatally. Causes include:

·        Cerebral malformation.

·        Hypoxia in utero and or peripartum.

·        Stroke in the perinatal period – cerebral haemorrhage or infarction.

·        Infection – intrauterine or postnatal. Trauma at birth or postnatal.

·        Prolonged convulsions or coma in infancy.

·        Kernicterus (severe jaundice leading to brain damage and seizures in the newborn).

Pathophysiology

As the lesion of CP arises early in development it interferes with normal motor development. The main handicap is usually one of disordered movement and posture but it is often complicated by other neurological and cognitive problems. CP is classified according to the clinical picture:

·        Spastic CP accounts for 70% involving damage to the cerebral motor cortex or its connections. The features are clasp like hypertonia, brisk reflexes, ankle clonus and extensor plantar responses. The condition may be a hemiparesis (one side of the body, arm more than leg), quadriparesis (both sides, arms more than legs) or diplegia (legs affected).

·        Dystonic (athetoid) CP accounts for 10%, and is characterised by irregular involuntary movements of some or all muscle groups. These may be continuous or occur only on voluntary movement.

·        Ataxic CP accounts for 10% and is characterised by hypotonia, weakness uncoordination and intention tremor.

·        Mixed CP makes up the remaining 10%.

Clinical features

Infants may present with poor sucking ability, increased or decreased tone, abnormal reflexes, convulsions or drowsiness in the neonatal period. However many such infants will develop normally. Usually CP can only be diagnosed after a few months when it becomes obvious that motor development is delayed. The persistence of primitive reflexes is also suggestive. The characteristic features described above may not present until later in childhood.

Complications

Mental retardation in 60%, epilepsy in 30%, visual impairment in 20%, hearing loss in 20%, orthopaedic deformities and osteoarthritis may result even with physiotherapy.

Investigations

Diagnosis is clinical.

Management

Multidisciplinary assessment and supportive treatment:

i.      1 Medication may be needed to control fits and hyperactivity. Muscle relaxants such as dantrolene or baclofen may be used for spasticity, and botulinum toxin injections may delay deformity due to muscle shortening.

ii.      Physical therapy is started in the first year of life, before abnormal motor patterns have become established.

iii.      Splintage is often required to counteract spastic deformities.

iv.      Persistent  deformities  may  require  corrective  orthopaedic surgery with post operative physiotherapy

Soft tissue procedures to improve muscle balance by rerouting or dividing tendons and muscles

Bone operations to correct position and stabilize joints

v.      Neurosurgical techniques are occasionally used for severe deforming spasticity to reduce spasm.

Prognosis

Most children with cerebral palsy survive to adulthood. Longer-term survival depends on their degree of disability, with those who never manage to feed or mobilise doing much worse, and often dying of aspiration pneumonia.