A palsy is defined as a “paralysis that is accompanied by involuntary tremors”. Cerebral palsy is a postural and movement disorder that occurs due to a non-progressive lesion of our motor pathways within the developing brain (a neurodevelopmental disease that does not worsen). It is ultimately damage to the cerebrum that results in a palsy, the most common reason for it is hypoxic ischaemic encephalopathy.
It affects 2 in 1000 births and is the most common cause of major motor impairment.
Pathophysiology
Cerebral palsy occurs due to damage to the developing brain and it can occur both prenatally (80%), intrapartum (10%) and postnatally (10%). This is because the brain begins development prenatally but continues to grow and develop postnatally for many years.
Prenatally | Intrapartum/peri-delivery | Postnatally |
Cerebrovascular haemorrhage or ischaemia (for example due to a placental bleed or placental abruption) | Hypoxic-ishcaemic injury | Infections - such as meningitis (most commonly due to Group B streptococcus) and encephalitis (due to HSV). |
Neuronal migration disorders - an umbrella term for abnormalities of the developing brain in utero. | Difficult delivery | Encephalopathy - may be due to infection or metabolic causes (such as hypoglycaemia or conditions leading to hyperammonemia). |
Structural maldevelopment - can sometimes be secondary to infections in-utero such as CMV, rubella and toxoplasmosis. | Foetal distress | Hyperbilirubinaemia & kernicterus |
Genetic mutations | Asphyxia due to cord around the neck | Hydrocephalus |
Preterm vulnerability: intraventricular bleeds and ischaemia and periventricular leukomalacia. | Trauma |
😷 Classification and presentation
Cerebral palsy can be variable as the manifestation of CP is dependant on the site and extent of the lesion. Let’s take a look at some of the categories of CP that may present:
- Spastic - this is most common (90%). It occurs when we have damage to our UMNs of the pyramidal pathways.
- Features include: pyramidal weakness, hypertonia, hyperreflexia, clasp-knife sign, flexed hip + elbow.
- Dyskinetic/athetoid - this is when we have damage to our basal ganglia pathways.
- Features include: athetoid movements (slow, Involuntary, writhing movements of the distal extremities), dystonia (involuntary, sustained contractions that result in twisting and abnormal postures), chorea (random dance-like movements).
- Ataxic - caused by damage to the cerebellar pathways.
- Features include: typical cerebellar lesion signs (ataxic/uncoordinated movements) and abnormal posture.
- Children can have mixed CP if 2+ motor types are present.
In addition to these types of cerebral palsy anf their presentations. Children with cerebral palsy often present with:
- Constipation
- Delay in speech development
- Delay in cognitive/intellectual development
🔢 Grading
The classification system for children aged 2-18 years is the Gross Motor Function Classification system (GMFCS). It is a measure of mobility function by representing the child’s present abilities as well as their limitations in gross motor function.
- Level I - walks unimpeded without assistive devices. Has impairments in advanced gross motor skills.
- Level II - walks mostly without assistive devices. Uses railings for stairs. Has difficulty walking outdoors on uneven terrain.
- Level III - walks with assistive devices such as crutches or a walker. May use a wheelchair for long distances.
- Level IV - limited self-mobility. Transported using a wheelchair or uses a power chair for their primary mobility. May walk for short distances with assistance.
- Level V - total dependence on others for wheelchair mobility. If using a power chair, it requires extensive adaptation.
🔍 Investigations
🏆 Diagnosis for cerebral palsy is primarily clinical, based on examination in which we assess active and passive range of motion, motor power, voluntary motor control, tone, sensation.
The most common delayed motor milestones in children with cerebral palsy are:
- Not sitting by 8 months.
- Not walking by 18 months.
- Early asymmetry of hand function (hand preference) before 1 year.
- 🏆 MRI brain should be given to every child with CP. About 80% of postnatal MRIs of the brain are normal in children with CP. If the presentation is typical, we can delay until the child is old enough to have a scan without sedation (~5-7 years).
- Periventricular leukomalacia (death of white matter near the ventricles)
- Congenital malformations
- Haemorrhage/stroke
- Cystic lesions.
We look for:
- Ultrasound is not as sensitive, but may aid diagnosis and prognosis.
🧰 Management
- Physiotherapy - to aid movement and strength.
- Occupational therapy - mobility aids, home adjustments, orthotics.
- Speech and language therapy - swallowing assessments.
- Dieticians - if there are swallowing difficulties, dieticians may address concerns of nutrition.
- Baclofen - for spasms. It is a central acting spasm reliever. It works through agonism of the GABAb receptor which is a Gi/o GPCR that is widespread in the CNS. It is given intrathecally.
- Diazepam - given orally. It is a long-acting BDZ that modulates the GABAa receptor.
- Botox injections - Botox type A is given. It works by SNARE cleavage, preventing vesicle release from the pre-synaptic membrane.
- Orthopaedic surgery - for MSK deformities, injuries, tendon releases.
- Selective dorsal rhizotomy - may also be done. It involves cutting the rootlet of the muscles producing abnormal contractions.
🚨 Complications
- Injuries due to impaired coordination.
- Aspiration pneumonia due to impaired swallowing.
- Pain in tight muscles
- Intellectual disabilities
- Speech and language disorders
- Visual and hearing impairments
- Urinary incontinence
- Sleep disorders
- Epilepsy
- Muscle wasting
- Scoliosis and MSK deformities.
Hypoxic-ischaemic encephalopathy (HIE) is a form of brain damage occurring in the antenatal/perinatal periods due to hypoxia. Some level of hypoxia is normal during birth, however, prolonged or severe hypoxia leads to ischaemic brain damage. It can lead to irreversible brain damage causing cerebral palsy or death.
It affects approximately 1-2 births per 1000 live full-term births. Incidence is higher in premature and low-birthweight infants.
Pathophysiology
As mentioned HIE occurs due to hypoxia or ischaemia. Causes of hypoxia or ischaemia may be:
- Maternal shock
- Intrapartum haemorrhage
- Prolapsed cord
- Nuchal cord (cord wrapped around the neck of the baby).
The ischaemia leads to primary neuronal death (immediately) and secondary reperfusion injury (delayed).
😷 Presentation and staging
We can use the Sarnat staging to classify the presentation from mild-severe:
Mild HIE
- Poor feeding, general irritability, hyper-alertness
- Resolves within 24 hours
- Normal prognosis
Moderate HIE
- Poor feeding, lethargy, hypotonia, seizures
- Resolves within weeks
- 40% develop cerebral palsy.
Severe HIE
- Reduced consciousness, apnoeas, flaccid and reduced/absent reflexes.
- Up to 50% mortality.
- Up to 90% develop cerebral palsy.
🔍 Investigations
We should suspect HIE in neonates if:
- There were events that could have increased the chance of hypoxia in the perinatal or Intrapartum period (such as difficult delivery, unchallenged cord, placental abruption etc.)
- Umbilical artery blood gas pH <7
- Poor Apgar score
- Features of HIE present
- Features of multi-organ failure
The Apgar score is a 5 component tool that is used to quickly assess the state of a newborn baby. The score is a gross assessment of current status and does not hold prognostic value long-term (although extended period of low Apgar scores are correlated with reduced neurological function). The components included are:
- Activity
- Pulse
- Grimace
- Appearance
- Respiration
Scores of:
→ 7+ are generally normal.
→ 4-6 is fairly low
→ 0-3 are seen as critically low and are cause for immediate resuscitation.
🧰 Management
Management requires input from neonatologists in the neonatal unit. This involves:
- Supportive care - including neonatal resuscitation, ongoing ventilation, circulatory support, nutrition, acid-base balance, seizure management.
- Therapeutic hypothermia - an option that is available in certain circumstances to help protect the brain from hypoxic injury. It involves actively cooling the core temperature of the baby using cooling blankets and a cooling hat. Their temperature is maintained between a carefully regulated temperature of 33-34ºC. Their temperature is measured with a rectal probe. It is continued for 72 hours, after which the baby is gradually warmed up to normal temperatures over 6 hours.
- Follow-up is carried out by a paediatrician and the multi-disciplinary team to assess their development and any lasting effects of the hypoxic event. .
The aims of therapeutic hypothermia are to reduce the inflammation and neurone loss. It reduces the risk of cerebral palsy, developmental delay, learning disabilities, blindness and death.