Cerebral Palsy

Definition

• Disorder of movement and posturing

• Caused by static brain lesion

• Acquired during the stage of rapid brain development

• Manifestations may change with growth and development

Epidemiology

Occurs in 1-5 in 1 000 live births. More common in advanced countries. Advanced perinatal care increases survival of brain-damaged children. Care only slightly reduces incidence of cerebral palsy . More common in socioeconomically disadvantaged.

Aetiology Aetiology

• Prenatal (30%)

  • Maternal infection - Toxoplasmosis . Rubella . Cytomegalovirus . Herpes . Syphilis

  • Maternal exposure - Alcohol . Drugs

  • Congenital brain malformations

• Perinatal

  • Birth weight <2500g>(25-40%)

  • Anoxia (10-20%)

• Postnatal (10%)

  • Meningitis

  • Head injury

  • Immersion

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Classification

• 1. Spastic

  • Most common (60% of cases)

  • Most amenable to surgery

  • Due to upper motor neuron involvement - mild to severe motor impairment

  • Characterized by increased muscle tone and hyperreflexia, with slow, restricted movements (because of co contraction of agonist and antagonists)

  • Spasticity is characterized by increased muscle activity with increasingly rapid stretch (clasp knife & clonus)

  • Contractures

  • hemiplegia (both limbs on one side): arm usually worse than leg - all hemiplegics will walk, regardless of treatment; present with toe walking only

  • diplegia : have more extensive involvement of the lower extremity than the upper extremity; most diplegics will eventually walk; IQ may be normal, strabismus is common; gait is typically characterized by a crouched gait, toe walking, and flexed knees; heel cord lengthening alone may exacerbate crouched gait;

  • paraplegia (both legs): sparing of arms

  • quadriplegia : look for oral, lingual, dys f(x); dysarthria;

• 2. Athetoid / Dyskinetic

  • Writhing movements. When excited, wriggle as if tickled.

  • 20% of cases

  • Result from basal ganglia involvement

  • Present w/ slow, writhing, involuntary movements

  • may affect the extremities (athetoid), or the proximal parts of limbs and the trunk (dystonic)

  • Hyperextended hips & knees with exaggerated stepping gait. Lean backwards, extending shoulder girdle & trunk.

  • Abrupt, jerky distal movements (Choreiform) also may occur;

  • Movements incr during with emotional tension and disappear during sleep.

  • Dysarthia is present and is often severe.

  • Intelligence normal (often above average)

  • Most difficult to correct with surgery - results are unpredictable & plaster immobilisation hazardous due to friction from constant movements.

• 3. Ataxic

  • 10% of cases

  • Involvement of the cerebellum or its pathways

  • Weakness, inco-ordination, and intention tremor produce unsteadiness, wide based gait, and difficulty with rapid or fine movements

  • Poorly amenable to surgical correction;

• 4. Hemiballistic

  • Sudden movements . As if throwing ball.

• 5. Hypotonic

  • Usually a stage through which an infant passes.

• 6. Combination

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Pathogenesis

1. Weakness

Upper motor neuron lesion causes

• Loss of voluntary movement

• Weakness

• Easy fatigability

2. Spasticity

• Feature of all lesions of pyramidal system . Cerebral, capsular, pontine, midbrain lesions

• Related to excessive activity of disinhibited spinal neurones

• Mediated via stretch reflex . Muscle spindles detect stretch and stimulate muscle to contract . Threshold regulated by descending tracts . Spasticity due to hyperactivity of stretch reflexes

• Tendon reflexes hypertonic . Clonus may appear

• Posture characteristic because some neurones more active than others

• Attempts to change position lead to resistance which quickly yields Clasp-knife phenomenon.

3. Contracture.

• Nature of muscle contracture is: Shortening of muscle-tendon unit due to failure to keep pace with growth of bones.

• Muscle adds sarcomeres at musculotendinous junction in response to constant stretch

• In normal children, walking and movement provide all the stretch needed. When muscles spastic, this mechanism cannot occur.

4. Deformity

• From unopposed muscle contracture.

• Hip dislocation. Persistent hip adduction leads to valgus of femoral neck. Persistent hip flexion leads to anteversion of femoral neck. Results in Acetabular dysplasia, Hip subluxation & Hip dislocation

Note:

• Spasticity - Abnormally increased contraction of a muscle in response to a stretch. Growth of muscles is impaired.

• Rigidity - Involuntary sustained contraction of a muscle not stretch-dependent. Growth of muscles is not impaired.

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Clinical features

1. Spastic quadriplegia. (25%)

• Initially child floppy and will not feed

• Choking during feeding from pseudobulbar palsy (difficult swallowing & chewing; dribbling)

• Fail to thrive

• Intelligence, vision and hearing affected

• Only 10-20% will walk

• Begin to walk up to age 7

• Usually mentally retarded

• Develop hip dislocation early and scoliosis.

2. Spastic diplegia.(30%)

• All developmental milestones delayed

• Most walk by age 4 .

3. Spastic hemiplegia (40%)

• Usually noticed at walking age

• Mean age of walking is 2-3 months later than normal.

• Limp and one-handedness noted

• Right-sided form may have speech delay

• Seizures common.

• Mild learning problems

• Hyperactivity

4. Monoplegia (5%)

Associated disorders

• Most common with total involvement

• Mental retardation

• Seizures

• Learning disorders

• Emotional and personality derangement

• Visual defects

• Hearing impairments

• Disorders of speech

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Assessment

History

• Abnormal birth history

• Prematurity

• Neonatal nursery

• Normal Developmental milestones (brackets are 95th percentile)

  • Head control -3 mths (6 mths)

  • Sitting independently - 6 mths (9 mths)

  • Crawling - 8 mths (never)

  • Pulling to stand - 9 mths (12 mths)

  • Walking -12 mths (18 mths)

Examination. (Also see CP Examination )

• Walking- Arm swing . Trunk leans forward. Scissoring (d.t. Hip flexion & adduction). Windswept posture . Knee flexion . Stride length reduced . Narrow walking base. Equinus. Lordosis . Co-ordination in turning. [ Gait Analysis ]

• Sitting - Legs forward or W . Upright or slouched.

• Kneeling eliminates contracture effect .

• Hips - Clinical signs of dislocation:

  1. Limited abduction, esp. with rapid stretch (grab test)

  2. Asymmetric knee height with pelvis level & knees flexed ( Galeazzi test )

  3. Windswept posture - one hip adducted & other side abducted

  4. Asymmetric leg length

  5. Hip flexion contractures

• Muscles:

  • Psoas

    • FFD of hip demonstrated by Thomas test

    • Increased lumbar lordosis and prominent bottom when standing

    • Decreased sacrofemoral angle on standing lateral x-ray

    • Reduced SLR because of flexed pelvis from FFD.

  • Hamstrings

    • Reduced SLR

    • Hip extension contracture

    • FFD at knee

    • Lumbar kyphosis and small bottom when standing

    • Knee flexed at beginning of stance phase

    • False equinus (flexed knee lifts heel from ground)

    • Internal femoral torsion (sitting in W position)

    • Inability to touch toes

    • Reduced popliteal angle (hip at 90o)

    • High patella (flexed knee and spastic quadriceps)

  • Adductors

    • Scissored gait if bilateral

    • Apparent leg length discrepancy if unilateral

    • Trendelenberg limp

    • Decreased hip abduction

    • Eventual hip dislocation

  • Quadriceps

    • Stiff-legged gait (knees never flex)

    • Inability to flex knee when hip extended means rectus is responsible

    • Ely test (child prone, flex knee, if hip flexes = rectus femoris tight).

  • Triceps surae

    • Ankle equinus

    • Tiptoe gait

    • Recurvatum at knee when heel goes down

    • Silverskold's Test - equinus improves with knee flexion = soleus tighter than gastrocnemius

• Neurology

  • Gross. Weakness

  • Clasp-knife phenomenon

  • Primitive reflexes

    • Moro reflex - Hold child at 45 ^o . Allow head to drop back . Arms and legs stick out in extension . Normally disappears by 4 mths.

    • Labyrinthine reflex - Tone reduced and arms and legs flex when child prone . Tone increased and arms and legs extend when child supine . Normally disappears by 6 mths.

    • Parachute reflex - When child held head down, both hands put out protectively . Appears at 5 mths.

• Upper limbs

  • General.

  • Look at resting position.

  • Look for contractures.

  • Assess joint stability

  • Hand placement. Ask patient to place hand on knee and then head.

  • Control.

    • Ask patient to pretend to play piano . Look for independent movement.

    • Ask patient to throw object. Look for grasp and release.

    • Stereognosis. Test ability to recognise shape in palm

• Predictors of Walking (from 1 year of age):

  1. Asymmetrical tonic neck reflex

  2. Symmetrical tonic neck reflex

  3. Neck righting reflex

  4. Moro reflex

  5. A pattern of extensor thrust & abduction of the legs when supported upright

  6. Parachute reflex

  7. Stepping reflex

  • If any 2 of these 7 responses are inappropriate by 1 year of age it is highly unlikely that the child will walk independently