Cerebral Palsy ✅ Flashcards
How do upper motor neuron lesions usually present?
Hypertonia
What is the most common disabling condition in children with hypertonia?
Cerebral palsy
What are the most disabling types of CP?
Spastic and dystonic types
What is lost in spastic and dystonic types of CP?
There is a loss of the usual balance of excitatory and inhibitory muscle control
What is CP?
A descriptive term which has been defined as ‘a group of permanent disorders of movement and posture causing activity limitation that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain’
What are the motor disorders of CP often accompanied by?
- Disturbances of sensation, perception, cognition, communication and behaviour
- Epilepsy
- Secondary musculoskeletal disorders
Are children with CP always hypertonic?
No
What are the four main clinical types of CP?
- Spastic
- Dystonic
- Ataxic
- Choreo-athetoid
What characterises spastic CP?
A velocity dependent increase in tonic stretch receptors
How must spasticity be assessed in spastic CP?
Must be dynamic
What is the spasticity described as in spastic CP?
‘Clasp knife’
What characterises dystonic CP?
Spasm and sustained contraction of muscles, leading to abnormal posturing
What can dystonic CP lead to over time?
Contractures
What is dystonic CP often described as feeling like?
Lead pipe rigidity
What characterises ataxic CP?
Uncoordinated movements linked to a disturbed sense of balance and depth perception
What characterises choreo-athetoid CP?
Hyperkinesia (excess of involuntary movements), which are often writhing in nature
What % of cases of CP are unilateral spastic?
25%
What areas of the brain are most commonly affected in unilateral spastic CP?
Infarction within the distribution of middle cerebral artery (left MCA distribution more commonly affected than right)
What are the potential causes of unilateral spastic CP?
- Intrapartum asphyxia
- Ischaemia (stroke) in late third trimester
- Intraventricular haemorrhage related to prematurity
What % of cases of CP are bilateral spastic?
55%
What is the more common type of bilateral spastic CP?
Roughly equal proportions diplegia to quadriplegia
What area of the brain is most commonly affected in bilateral spastic CP?
- Bilateral cerebral hemisphere infarction
- Cerebral dysgenesis
What are the most common causes of bilateral spastic CP?
- Genetic
- Infections in early pregnancy, e.g. CMV, toxoplasmosis
- Vascular accidents/malformations
What are the less common causes of bilateral spastic CP?
- Neonatal meningitis or metabolic insult
- Postnatal causes
What % of cases of CP are dyskinetic?
15%
What area of the brain is most commonly affected in dyskinetic CP?
Discrete gliotic lesions in the putamina and thalami
What are the potential causes of dyskinetic CP?
- Acute profound asphyxia in the late third trimester or intrapartum
- Bilirubin encephalopathy
What are some causes of intrapartum asphyxia?
- Cord prolapse
- Antepartum haemorrhage
- Uterine rupture
What % of cases of CP are ataxic?
5%
What are the most common causes of ataxic CP?
- Abnormal development of cerebellum
- Dysmorphic syndromes
What are the less common causes of ataxic CP?
- Postnatal infection or trauma
Do children with CP always fit into one category?
No, they often have a mixed picture of movements
What is the Gross Motor Function Classification System used for?
To describe the functional ability of a child’s gross motor skills
What other conditions can mimic CP?
- Spinal cord tumours
- Channelopathies
- Sandifer syndrome
- MECP2 duplication
- Congenital dopa-responsive disorders
- Genetic spastic paraplegia
- Some metabolic conditions
- Ataxia telangiectasia
Give 2 examples of metabolic conditions that can mimic CP?
- GLUT1 deficiency
- Glutaric aciduria type 1
When does particular care need to be taken in the diagnosis of CP to check there is no underlying cause?
- When there is a family history, to ensure not an underlying inheritable cause
- When child presents with ‘ataxic cerebral palsy’
What is required to meet a child with CP’s complex needs?
MDT approach
What are the potential sites of action of drugs that manage spasticity?
- Motor cortex
- Spinal cord
- Muscle
What kind of drug is diazepam?
Gamma-aminobutyric acid (GABA) agonist
What is GABA?
The principal inhibitory neurotransmitter regulating neuronal excitability in the nervous system
What does GABA have a direct effect on?
Muscle tone
What is the result of GABA acting centrally?
It relieves spasticity and muscle spasm, but has additional effects of sedation and acts as an anxiolytic
What can long-term use of GABA lead to?
Dependency
What is short term use of GABA useful for?
Painful spasms, e.g. after surgery, or to break cycles of distress and increasing spasticity
What kind of drug is baclofen?
A GABA agonist
At what level does baclofen inhibit neuronal transmission?
At a spinal level
What is the main adverse effect of baclofen?
Sedation
Is sedation a significant side effect of baclofen?
Yes, it often limits its use
Why are high doses of baclofen often needed?
Because its passage into the CSF when given orally is poor
How can the dose requirement of baclofen be reduced?
By using intrathecally
How is baclofen given intrathecally?
Via a surgically implanted continuous-delivery pump
What is the advantage of giving baclofen intrathecally?
Only a tiny fraction of the equivalent oral dose needs to be given, which allows greater efficacy with fewer adverse effects
What kind of drug is tizanidine?
An alpha-2 adrenergic receptor agonist
Where does tizanidine act?
At the spinal level
Who is tizanidine particularly useful in?
Children who are severely disabled by CP, and in those with night-time spasms
Why is tizanidine useful in night-time spasms?
As it commonly has a sedative effect
How does botulinum toxin A work?
By chemically denervating the muscle, allowing the muscle to relax and thus improving function and cosmesis in some cases
How does botulinum toxin A act?
By cleaving synaptosomal-associated protein (SNAP-25)
What is SNAP-25?
A cytoplasmic protein which aids in the process of attaching the synaptic vesicle to the pre-synaptic membrane
What is the effect of cleaving SNAP-25?
It stops the release of acetylcholine at the synapse, and blocks neurotransmission
What happens to the effects of botulinum toxin A over time?
Gradually wear off over 3-6 months
Why do the effects of botulinum toxin A gradually wear off?
Because the myelin sheath retracts and new terminals are made, which form contacts with the myocyte to resume neurotransmission
How does dantrolene work on spasticity and spasms?
By affecting calcium uptake into skeletal muscles and decreasing free intracellular calcium concentration
Is sedation a problem with dantrolene?
Less so than other drugs used in CP
Why should dantrolene be caused cautiously?
It can cause hepatic dysfunction and blood dyscrasias
What non-drug treatment may be used for spasticity?
Selective dorsal rhizotomy (SDR)
When is SDR particularly used in treating spasticity in CP?
In more mobile groups of children with CP (GMFCS levels 2-3)
What happens in SDR?
Surgical procedure to divide some of the lumbar sensory nerve roots
Why does dividing lumbar sensory nerve roots in SDR improve spasticity?
It interrupt the sensory-motor reflex arc responsible for increased muscle tone
What should pre-op assessment for SDR include?
Bladder assessment
Why is bladder assessment required prior to SDR?
Due to the risk of affecting continence
What is the limitation of SDR?
The child’s general level of gross motor function unlikely to change significantly
What is the benefit of SDR?
May be improvements in quality of gait, and improved comfort and ability to tolerate splints and postural management programmes
