- Non-progressive upper motor neuron disease (static encephalopathy) due to injury to immature brain
Epidemiology
- Onset is before first two years of life
- Most common cause of chronic childhood disability
- Slightly more common in males
- Higher incidence in low income countries
Etiology
- Antenatal factors
- Prematurity
- Maternal infection – TORCH
- Neonatal vascular incidents – emboli from placental thrombosis
- Perinatal factors
- Birth asphyxia due to instrumental delivery
- Non-vertex presentation
- Placental abruption
- Post natal factors
- Hyperbilirubinemia
- Neonatal sepsis
- Respiratory distress
- Head injury – child abuse, shaken baby syndrome
Types
Spastic (most common)
- Caused by damage to the motor cortex – responsible for the planning and completion of voluntary movement
- Characterized by spasticity or high muscle tone – results in stiff, jerky movements
- Umbrella term, encompasses
- Spastic hemiplegia – affects one vertical half of the body e.g. one arm and one leg
- Spastic diplegia – predominantly affects the legs
- Spastic quadriplegia – affects all four limbs
Ataxic (least common)
- Caused by damage to cerebellar structures – responsible for coordinating muscle movements and balance
- Clinical features
- Problems in coordination – especially in arms, legs, and trunk
- Decreased muscle tone
- Intention (action) tremor – occurs when carrying out a specific, deliberate movement e.g. tying shoe laces, writing etc
- Tremor intensifies as the hand gets closer to accomplishing the intended task
Dyskinetic
- Caused by damage to the basal ganglia and the substantia nigra – e.g. in bilirubin encephalopathy and hypoxic-ischemic brain injury
- Extrapyramidal form of cerebral palsy – divided into two groups
- Choreoathetosis – characterised by involuntary movements
- Dystonia – characterized by slow, strong contractions; can occur locally or encompass the whole body
- Clinical diagnosis of usually occurs within 18 months of birth – based on motor function and neuroimaging
Classification – Gross Motor Function Classification Scale (GMFCS)
- Level I – near normal gross motor function, independent ambulator
- Level II – walks independently, but with difficulty on uneven surfaces, minimal ability to jump
- Level III – walks with assistive devices
- Level IV – severely limited walking ability, mainly uses wheelchair
- Level V – nonambulator, dependent in all aspects of care
Orthopaedic clinical features
- Contractures
- Fractures
- Upper extremity deformities
- Shoulder internal rotation contracture
- Forearm pronation deformity
- Wrist flexion deformity
- Thumb in palm deformity
- Hip subluxation and dislocation
- Spinal deformity
- Scoliosis – more likely to progress than idiopathic scoliosis
- Foot deformities
- Equinus
- Hallux valgus
- Equinoplanovalgus
- Equinocavovarus
- Gait disorders
- Equinus gait
- Jump gait
- Crouch gait
- Stiff knee gait
Diagnosis
- Clinical and Perinatal history
- Physical exam – general musculoskeletal exam, gait, spine, hip, foot, ankle
- X-ray
- MRI – shows changes in the brain
- Periventriuclar leukomalacia white matter lesions (most common)
- Brain malformations
Treatment
Non-operative
- Physiotherapy
- Bracing
- Medication for spasticity
- Botulinum A – competitive inhibitor of presynaptic cholinergic receptors
- Baclofen – GABA agonist, reduces muscle tone
Operative
- Soft tissue releases – to improve function in a child (3-5 years old) with spasticity
- Tenotomy, tendon lengthening, tendon transfer
- Selective dorsal rhizotomy – neurosurgical resection of the nerve rootlets in the spinal cord that are sending abnormal signals to the muscles. Corrects muscle spasticity
- SEMLS surgery – Single Event, Multi-level Surgery
- To limit multiple surgeries and decreased rehabilitation time