Descriptive
term for a broad group of clinical syndromes that is characterised
by a chronic, static, non-progressive disorder of motor control
due to an injury to the nervous system -->resulting in abnormalities
of posture, muscle tone and motor control.
Occurs
in 1 to 5/1000 births – higher incidence in premature low
birthweight infants.
Lesion
causing cerebral palsy is non-progressive, but resultant deformities
can be progressive.
Aetiology:
Exact aetiology is not clear, but most commonly cited cause
is foetal anoxia – especially an intraventricular haemorrhage
in preterm infants.
Many
conditions can injure the developing brain:
• prenatal – infections (eg rubella); maternal alcohol
and drug abuse; congenital deformity; genetic disorders; exposure
to toxins or radiation; cerebral infarcts
• perinatal – prematurity; birth trauma; delivery complications
• postnatal – infections (eg meningitis); traumatic
injury to CNS; anoxia (eg near drowning); acute metabolic disorders;
blood group incompatibility
Factors
associated with increase risk of cerebral palsy include
• respiratory distress syndrome
• foetal malformations
• birth weight <2100g
• maternal intellectual impairment
• delayed first cry
• neonatal seizures
Clinical
features:
50% diagnosed in first 6 months.
Early diagnosis of mild cases is difficult
Types:
Cerebral palsy can be classified in a number of ways depending
on tonus variations, distribution of tonus changes, severity, functional
ability and type:
Swedish
Classification:
1. Spastic:
• hemiplegic (upper limb and lower limb on same side; contractures
more severe distally; feet in equinus and/or varus; scoliosis is
common; walking delayed); diplegic (both lower limbs more involved
than upper limbs; most common type; ); monoplegic (single limb involved);
triplegic; quadriplegic (all four limbs equally involved)
• most common type
• due to injury in pyramidal system
• usually present with hypertonia, rigidity, tendon reflexes
exaggerated’ persistence of primitive reflexes
2. Dyskinetic:
• dystonic (bizarre positions and movements of limb); choreoathetotic
(irregular writhing movements; variable muscle tone); hypotonic
(lack or reduced muscle tone)
• impaired voluntary muscle control (slow writhing movements
of flexion/extension and pronation/supination of feet and hands)
• assumed to be due to lesion in basal ganglia
3. Ataxic
• complete or partial lack of muscle coordination and decrease
in proprioception ? balance problems
• due to injury in cerebellum
• rarer form
4. Mixed
• combination of types --> variety of movement disorders
Associated
disabilities:
• intellectual impairments and learning disabilities
are common
• increased frequency of seizures
• up to a third have visual problems
• up to 10% have hearing defects
• 50% have speech and language problems
The
foot in cerebral palsy:
Undiagnosed mild cases may present to Podiatrist due to
involvement of foot (most often a severe pes planus/pronated foot)
Pattern of foot deformity depends on type and extent of involvement.
Most common is a spastic equinus caused by an unbalanced action
of the extensor and flexor muscles with prolonged activity of the
calf muscles
Torsional problems of the limbs are common.
Management:
Multidisciplinary
Occupational
therapy -
Adaptive equipment (eg devices for standing); mobility aids (eg
wheelchairs)
Night splints
Botulinum
toxin
Cast
correction
Equinus – if mild --> stretching and orthoses; if severe
--> surgery
Orthoses
– used to facilitate function, inhibit reflex activity, prevention/correction
of deformity
Online
resources for cerbral palsy
ePodiatry's
resources on cerebral
palsy
Spinal Dysraphism (Spina
bifada occulta – myelomeningocele)
Group
of congenital malformations due to a failure of the two halves of
some spinous vertebrae to fuse, leading to a defect in the vertebral
column. Affects about 2 in 1000 live births. Severity varies from
an asymptomatic spina bifada occulta to myelomeningocele. Defects
can be open or closed and generally need surgical repair of the
lesion.
Foot
deformity:
Present in most cases. Loss of protective sensation and proprioception
- pressure lesions post-surgical correction of deformity.
Charcot-Marie-Tooth Disease(CMT)/Type
1 HMSN
Type
1 hereditary motor and sensory neuropathy (HMSN) is an inherited
disorder characterised by degeneration of the posterior columns
of the spinal cord, loss of anterior horn cells with degeneration
of the spinocerebellar tracts, demyelination of peripheral nerves.
Prevalence of 41/100 000.
Clinical
features:
Usually onset is around 5 years (first concern may be difficulty
fitting shoes). Characterised by atrophy of the peroneals and intrinsic
muscles with a pes cavus foot - may present with pain under lateral
forefoot. Pes cavus develops as muscle weakness primarily affects
peroneus brevis and tibialis anterior with peroneus longus being
spared - plantarflexion of first ray. Mild cases are often misdiagnosed
as pes cavus and not investigated further. Initial symptoms are
the peroneal brevis weakness and a ‘foot slap’ with
falls and tripping. Patients generally notice a feeling of weakness
in the legs. Then get progressive loss of vibration sensation and
proprioception. Rearfoot and first ray are usually initially flexible,
later becomes fixed.
Treatment:
• conservative management of symptoms of pes cavus
• surgical correction of foot deformity.
Online
resources:
ePodiatry's
resources on Charcot
Marie Tooth disease
Peroneal Muscle Atrophy/Type
2 HMSN
Characterised
by axonal degeneration of peripheral nerves and is clinically similar
to CMT. Foot plantarflexes are involved to a greater extent than
CMT - due to profound distal muscle weakness and wasting ? ‘stork
legs’. Develop a ‘flail foot’ that may be in varus
or valgus
Dejerine-Sottas Disease/Type
3 HMSN
Autosomal
recessive. Characterised by hypertrophic interstitial neuropathy
and is pathologically similar to CMT. Begins in infancy. Motor milestones
are delayed and sensation is impaired – reflexes absent. Develop
pes cavus and drop foot deformities. Spinal deformities ? usually
confined to wheelchair.
Refsum’s Disease/Type
4 HMSN
Characterised
by anorexia, gait abnormalities, ichthyosis, night blindness, eye
complications, hearing deficits, polyneuropathy with distal muscle
weakness and muscular atrophy. Loss of sensation and pes cavus are
common.
Friedreich’s Ataxia
Spinocerebellar
degenerative disease with involvement of peripheral nerves and posterior
columns of spinal cord. Characterised by progressive, clumsy ataxic
gait. Mean age of onset is 10 years – presenting feature is
gait instability and falling. Most develop pes cavus, claw toes,
wasting of intrinsic muscles --> progresses to loss of strength
in all lower limb muscles – trunk and upper limb affected
late. Also loose proprioception and vibration sensation. Deep tendon
reflexes are diminished or lost. Mean age of wheelchair use is about
20 years.
Duchenne Muscular Dystrophy
(DMD)
Most
common muscular dystrophy; x-linked recessive disorder – mutation
of chromosome at location p21 (dystrophin gene) ? reduced or impaired
dystrophin (stabilises cell membrane within muscle cell); affecting
boys – usually starts before 5 years (mean age of presentation
is 3.5yrs); affects about 1/3500 male births;
Clinical
features:
Pelvic girdle affected first with proximal muscles initially showing
signs of weakness --> clumsy waddling gait. Delayed motor milestones
- tend to walk run at later age than peers (early motor development
often normal or slight delay). May have trouble climbing stairs
or getting up from the floor (Gower’s sign). Protuberant abdomen
from lumbar lordosis. Progressive --> distal limbs become affected.
Calf muscles enlarged from fat cells replacing muscle.
Usually in wheelchair by 10-12 years and usually die of cardiovascular
complications before age 30.
Calf muscle contracture --> equinus and toe walking a common
early sign
Laboratory
findings – creatine kinase elevated up to 20x
Management:
No cure; adaptive equipment; prednisone can delay onset of loss
of ambulation by up to 2 years; surgical management of scoliosis
Lower
limb – stretching and night splints for equinus; surgical
release of contracture may keep ability to walk
Becker Muscular Dystrophy
(BMD)
X-linked
recessive. Similar to Duchenne Muscular Dystrophy – but more
protracted and less common (1/30 000 live male birth) and later
onset.
Clinical
features:
Usually able to walk until early adulthood – often live to
30’s
Associated with cardiac problems.
Equinus
and toe walking is common.
Online
reources:
ePodiatry's
resources on muscular
dystrophy |
