Neurological disability Flashcards
What is the definition of cerebral palsy?
= a permanent disorder of movement and of motor function due to a non-progressive abnormality of the developing brain
What is the most common motor impairment of children?
Cerebral palsy
How common is cerebral palsy?
2 per 1000
What proportion of cerebral palsy cases are antenatal in origin?
80%
What proportion of cerebral palsy cases are perinatal in origin?
10%
What proportion of cerebral palsy cases are postnatal in origin?
10%
What are the antenatal causes of CP?
1) Cerebrovascular haemorrhage or ischaemia
2) Cortical migration disorders
3) Structural maldevelopment of the brain
4) Congenital infection (e.g. CMV)
What are the perinatal causes of CP?
HIE before/during delivery
What are the postnatal causes of CP?
1) Meningitis/encephalitis/encephalopathy
2) Head injury
3) Symptomatic hypoglycaemia
4) Hydrocephalus
5) Hyperbilirubinaemia
What are the antenatal RISK FACTORS for CP?
1) Pre-term birth
2) Chorioamnionitis
3) Maternal respiratory tract/GU infection requiring hospital treatment
What are the perinatal RISK FACTORS for CP?
1) LBW
2) Chorioamnionitis
3) Neonatal encephalopathy
4) Neonatal sepsis
5) Maternal respiratory tract/GU infection requiring hospital treatment
How might CP appear on MRI?
- White matter damage
- Basal ganglia or deep grey matter damage
- Congenital malformation
- Focal infarcts
What are the most commonly delated motor milestones seen in CP?
- Not sitting by 8 months
- Not walking by 18 months
- Early asymmetry of hand function (hand preference) before 1 year
How may CP be categorised?
- Spastic (90%)
- Dyskinetic
- Ataxic
- Other
What is the pathophysiology behind spastic CP?
Damage to the UMN pathway - pyramidal or corticospinal tract
What are the different types of spastic CP?
- Unilateral (hemiplegia)
- Bilateral (quadriplegia)
- Bilateral (diplegia)
How do children with hemiplegic spastic CP tend to present?
Between 4-12 months
Fisting of the affected hands, flexed arm and pronated forearm
Describe typical features of a child with quadriplegic spastic CP:
All limbs involved
Poor head control
Trunk involved, tendency for extensor posturing
Associated with seizures, microcephaly, intellectual, speech, vision, hearing and feeding impairments
Describe the typical features of a child with diplegic spastic CP:
All limbs affected, but legs to a much greater extent
Young children will walk on their toes with scissoring of their legs
Older children may adopt a crouching gait pattern as they gain weight and are no longer able to walk sustained periods on tip-toes
What type of CP is most commonly associated with preterm birth and PVL?
Diplegic spastic CP
What defines dyskinetic CP?
Involuntary uncontrolled movements - may be 1) chorea (irregular, brief, repetitive); 2) athetosis (slow writhing movements occurring more distally, e.g. finger fanning) or 3) dystonia (twisting appearance of movement)
What is the pathophysiology of dyskinetic CP?
Damage to the basal ganglia and their associated (extra-pyramidal) pathways
How will children with dyskinetic CP typically look?
Open mouth posture with internal rotation and extension of the arms
How is CP managed?
By the MDT
What are some novel approaches to treating hypertonia?
1) Botox
2) Selective dorsal rhizotomy - proportion of nerve roots in the spinal cord = selectively cut to reduce spasticity
3) Intrathecal baclofen
4) Deep brain stimulation of the basal ganglia
What are the types of disorder that can result in a floppy (hypotonic) infant?
- Disorders of the anterior horn cell
- Disorders of the peripheral nerve
- Disorders of the neuromuscular transmission
- Muscle disorders
What are the disorders of the anterior horn cell?
- SMA
2. Poliomyelitis
What are the disorders of the peripheral nerve?
- Bells palsy
- Guillan-Barre
- Hereditary motor sensory neuropathies
What are the disorders of the neuromuscular transmission?
- Myasthenia gravis
What are the muscle disorders?
- DMD
- Becker muscular dystrophy
- Congenital muscular dystrophy
- Metabolic myopathies
- Congenital myopathies
- Polymyositis/dermatomyositis
- Benign acute myositis
What is the most common neuromuscular disorder in children?
DMD
What is the second most common neuromuscular disorder in children?
SMA
How is SMA inherited?
Autosomal recessive
How is DMD inherited?
X-linked recessive, but approx. 1/3rd = de novo mutations
How can DMD be Dx?
Clinically + markedly elevated plasma CK
What is the pathophysiology of DMD?
Mutation in DMD gene results in absence of dystrophin
Absence = influx of Ca2+, breakdown of Ca2+ calmodulin complex + excess of free radicals
Results in myofibre necrosis
What are the 3 classical features of DMD?
- Waddling gait
- Gower’s sign
- Pseudo-hypertrophy
What causes calf pseudo-hypertrophy?
Muscle fibres are replaced by fat and fibrous tissue
Becker muscular dystrophy is caused by a mutation in which gene?
DMD also - it is allelic to Duchenne’s = different mutation, same gene
Why is Becker’s clinically milder + progresses more slowly than Duchenne’s?
Some functional dystrophin is produced
What is the location of 60% of childhood brain tumours?
Infratentoril (i.e. below the tentori cerebelli)
What are the 2 types of hydrocephalus?
- Non-communicating - obstruction in the ventricular system
2. Communicating - failure to resorb CSF
What can cause non-communicating hydrocephalus?
- Congenital malformation - e.g. aqueduct stenosis, chiari malformation, atresia of outflow foramina of the 4th ventricle
- Posterior fossa neoplasm or vascular malformation
- IVH in pre-term infant
What can cause communicating hydrocephalus?
- Subarachnoid haemorrhage
2. Meningitis
Is shunt infection were to occur, what is the most common causative organism?
Coagulase -ve staphylococci
What is the definition of microcephaly?
Head circumference >2 SDs BELOW the mean for age and sex
What are the congenital causes of microcephaly?
- Familial/inherited
- Syndromes - e.g. Down’s, William’s, DiGeorge
- Congenital infection - e.g. CMV, zika, rubella, toxoplasmosis
- Drugs - e.g. alcohol
- Other - e.g. maternal radiation, PKU, hypothyroidism
What are the post-natal onset causes of microcephaly?
- Inborn errors of metabolism
- Syndromes - e.g. Rett syndrome
- TBI/HIE/stroke
- Infection - e.g. meningitis
- Toxins - e.g. chronic renal failure, lead poisoning
- Deprivation (of nutrient/hormone etc.) - e.g. anaemia, hypothyroidism, CHD
