Neurology: Cerebral Palsy & Strabismus (squint) Flashcards
What is cerebral palsy (CP)?
A disorder of movement and posture due to a non-progessive lesion of the motor pathways in the developing brain.
Is cerebral palsy progressive?
No - however the nature of the symptoms and problems may change over time during growth and development.
Results from damage to the brain around the time of birth
Variation in presentation of CP?
There is huge variation in the severity and type of symptoms, ranging from completely wheelchair bound and dependent on others for all activities of daily living, to para-olympic athletes with only subtle problems with coordination or mobility.
CP can be caused in the antenatal, intrapartum or postnatal period.
Which is most common?
Antenatal (80%)
Give some antenatal causes of CP
1) Cerebral malformation
2) Maternal infections (TORCH)
3) Trauma during pregnancy
4) Chorioamnionitis
What congenital/maternal infections can cause CP?
TORCH infections –> toxoplasmosis, rubella, CMV, and herpes simplex
Give 4 intrapartum risk factors for CP
1) Birth asphyxia/trauma
2) Prematurity (significant risk factor)
3) Low birth weight
4) Neonatal sepsis
Give 4 postnatal causes of CP
1) Intraventricular haemorrhage
2) Meningitis
3) Head-trauma
4) Severe hyperbilirubinaemia (neonatal jaundice)
What are the 4 types of CP?
Cerebral palsy can be classified based on which clinical features predominate in an individual.
1) spastic (most common)
2) dyskinetic
3) ataxic
4) mixed
What is spastic CP?
Causes velocity-dependent hypertonia (spasticity) and hyperreflexia.
In this type of CP, when a limb is moved quickly the muscle can suddenly increase in tone and stop further movement (a spastic catch).
What is damaged in spastic CP?
Upper motor neurones
What characterises dyskinetic CP?
This involves involuntary, uncontrolled, recurring movements, fluctuating muscle tone and persistent primitive reflexes.
Associated with hypertonia and hypotonia.
Can cause athetoid movements and oro-motor problems.
What is damaged in dyskinetic CP?
Basal ganglia
What is ataxic CP?
This involves problems with coordinated movement - characterised by loss of muscular coordination resulting in ataxia and tremor.
What is damaged in ataxic CP?
Cerebellu,
What is mixed CP?
A mix of spastic, dyskinetic and/or ataxic features
Does spastic CP involve hypo- or hypertonia?
Hypertonia
Does dyskinetic CP involve hypo- or hypertonia?
Both
What do the clinical features of CP depend on?
The area of the brain affected.
What are the 2 subtypes of dyskinetic CP?
1) Dystonic CP
2) Choreoathetotic CP
What is seen in dystonic CP?
Abnormal posturing and hypertonia
What is seen in choreoathetotic CP?
Chorea & athetosis
Cerebral palsy can also be classified by which part of the body is most affected.
What are the 4 classifications?
1) Monoplegic –> affects one limb
2) Hemiplegic –> affects one side of body
3) Diplegic –> cerebral palsy is symmetrical, with the lower limbs more affected than the upper limbs
4) Quadriplegic –> indicates all four limbs are severely affected.
Are lower or upper limbs more affected in diplegic CP?
Lower limbs
What is hypertonia?
the general term for increased resistance in the muscles.
What is spasticity?
Spasticity is velocity-dependent, meaning the faster you move a limb, the higher the tone you will feel.
What is dystonia?
Dystonia refers to abnormal postures which are worse on intention.
An easy way to remember the difference between the two is that you feel spasticity but you can see dystonia.
How does CP typically present?
Delayed motor milestones:
- Not sitting by 8 months
- Not walking by 18 months
- Hand preference before 12 months
Other clinical features of CP?
1) Tone abnormalities (floppiness or stiffness)
2) Abnormal movements (e.g. asymmetrical movements, fidgety movements, lack of movement)
3) Feeding problems such as choking or dysphagia
4) Persistent toe walking
Should there be regression in milestones in CP?
No - This is a red flag in any child and would suggest an alternative diagnosis.
Children with cerebral palsy often have associated non-motor problems.
What are some examples?
1) learning difficulties (60%)
2) epilepsy (30%)
3) squints (30%)
4) hearing impairment (20%)
How is a diagnosis of CP made?
Cerebral palsy is a clinical diagnosis, and there are no definitive diagnostic tests.
What are the conservative management options in CP?
1) Physiotherapy
2) Occupational therapy
3) Speech and language therapy
4) Dietician input
Aim of occupational therapy input in CP?
Used to help patients manage everyday activities e.g. getting dressed and using the bathroom.
They can also make adaptations and supply equipment, such as rails for assistance or fitting a hoist for a patient who is entirely wheelchair bound.
Role of SALT in CP?
Can help with speech and swallowing. When swallowing difficultly prevents them meeting their nutritional requirements they may require an NG tube or PEG tube to be fitted.
What can medical management of CP involve?
1) Baclofen (muscle relaxant) –> for muscle spasticity and contractures (i.e. hypertonia)
2) Anti-epileptic drugs for seizures
3) Glycopyrronium bromide or hyoscine hydrobromide –> for excessive drooling
4) Diazepam –> pain
5) Botulinum toxin type A injections –> used if spasticity is severely affecting function or causing significant pain
What can surgical management of CP involve?
1) Hip displacement correction
2) Tenotomy –> procedures to release contractures or lengthen tendons
What are some complications of CP?
- Problems with feeding and aspiration
- Drooling
- Constipation
- Visual and hearing impairment
- Epilepsy
- Learning disability
- Speech difficulty
- Osteopenia and osteoporosis (especially if non-mobile)
- Sleep disturbance
What does a hemiplegic/diaplegic gait indicate?
An UMN lesion
What does a broad based/ataxic gait indicate?
Cerebellar lesion
What does a high stepping gait indicate?
Foot drop or a LMN lesion
What does a waddling gait indicate?
Pelvic muscle weakness due to myopathy
What does an antalgic gait (limp) indicate?
Localised pain
Muscle bulk in UMN vs LMN lesion?
UMN –> muscle bulk preserved
LMN –> reduced muscle bulk with fasciculations
Tone in UMN vs LMN lesion?
UMN –> hypertonia
LMN –> hypotonia
Power in UMN vs LMN lesion?
UMN –> slightly reduced
LMN –> dramatically reduced
Reflexes in UMN vs LMN lesion?
UMN –> brisk
LMN –> reduced
Patients with cerebral palsy may have a hemiplegic or diplegic gait.
What is this caused by?
This gait is caused by increased muscle tone and spasticity in the legs.
How will a hemiplegic or diplegic gait present?
The leg will be extended with plantar flexion of the feet and toes.
This means they have to swing the leg around in a large semicircle when moving their leg from behind them to in front. There is not enough space to swing the extended leg in a straight line below them.
Neuro exam findings in CP?
1) hemiplegic or diplegic gait
2) UMN lesion signs:
- good muscle bulk
- increased tone
- brisk reflexes
- slightly reduced power
3) Power may be normal.
4) Look for athetoid movements that indicate extrapyramidal (basal ganglia) involvement.
5) Test for coordination to look for cerebellar involvement.
What is a differential diagnosis of an UMN lesion?
1) CP
2) Acquired brain injury
3) Tumour
What is strabismus?
Misalignment of the eyes.
What are the 2 types of squints?
1) Concomitant squints (common)
2) Paralytic squints (rare)
What is the result of an untreated squint?
Amblyopia (a lazy eye).
This is due to the brain coping with this misalignment by reducing the signal from the less dominant eye.
As this progresses, this “lazy eye” becomes progressively more disconnected from the brain.
Cause of concomitant squints?
Due to differences in the control of the extraocular muscles.
The severity of the squint can vary.
Cause of paralytic squints?
Due to paralysis of one or more of the extraocular muscles
Define amblyopia
The affected eye becomes passive and has reduced function compared to the other dominant eye.
Define esotropia
Inward positioned squint (affected eye towards the nose)
Define exotropia
Outward positioned squint (affected eye towards the ear.
Define hypertropia
upward moving affected eye
Define hypotropia
downward moving affected eye
Causes of squints in children?
1) usually idiopathic
2) hydrocephalus
3) cerebral palsy
4) space occupying lesions e.g. retinoblastoma
5) trauma
What 2 tests can be used to diagnose a squint?
1) Hirschberg’s test
2) Cover test
What does Hirschberg’s test (i.e. corneal light reflection test) involve?
1) Shine a pen-torch at the patient from 1 meter away.
2) When they look at it, observe the reflection of the light source on their cornea.
3) The reflection should be central and symmetrical.
4) Deviation from the centre will indicate a squint.
5) Make a note of the affected eye and the direction the eye deviates.
What does the Cover test involve?
1) Cover one eye and ask the patient to focus on an object in front of them.
2) Move the cover across to the opposite eye and watch the movement of the previously covered eye.
3) If this eye moves inwards, it had drifted outwards when covered (exotropia) and if it moves outwards it means it had drifted inwards when covered (esotropia).
When does treatment for squints need to start?
<8 years (as up until 8 years, the visual fields are still developing).
Delayed treatment increases the risk of the squint becoming permanent.
1st line management of a squint?
1) referral to secondary care
2) an occlusive patch can be used to cover the good eye and force the weaker eye to develop
What is an alternative to an occlusive patch for a squint?
Atropine drops in the good eye, causing vision in that eye to be blurred.
