Overview of cerebral palsy

Cerebral palsy (CP) is a group of conditions that affect movement and posture, leading to activity limitations. It results from damage to the developing brain of a fetus or infant and doesn't get worse over time. Besides movement issues, CP often has problems in sensation, thinking, communication, perception, behaviour, and sometimes seizures.¹

Classification of cerebral palsy

Quadriplegic CP

This is the most severe form of CP, affecting all four limbs and the trunk, with the upper limbs being more severely impacted than the lower limbs. It is often associated with severe oxygen deprivation at birth. Neuroimaging often shows extensive brain damage, including cystic degeneration and various developmental abnormalities. Children with this type have very limited voluntary movements and may experience changes in blood flow to the extremities. They often have trouble swallowing, leading to frequent aspiration of food, and half of the patients have vision problems and seizures. Intellectual impairment is severe.

Hemiplegic CP

This type affects one side of the body, with the upper limb more severely impacted than the lower limb. It is seen in 56% of term infants and 17% of preterm infants and has multiple causes. Voluntary movements, especially hand functions, are impaired. The affected side has increased muscle tone, leading to a characteristic posture. Sensory abnormalities, such as impaired ability to recognise objects by touch and poor sense of position, are common. More than 50% of these patients have seizures, and they may also have visual field defects and cranial nerve issues, like facial nerve palsies.

Diplegic CP

This type is common in premature and low birth weight infants. It primarily affects the lower limbs more than the upper limbs. Nearly all preterm infants with this type show brain damage on imaging. The brain injury, known as periventricular leukomalacia (PVL), affects the white matter near the brain's ventricles. This condition often leads to CP, intellectual impairment, or visual disturbances. Lower limb rigidity and spasms are common, leading to a characteristic scissoring of the legs. Seizures and vision problems are also associated with PVL.²

Aetiology and risk factors

Cerebral palsy (CP) has a wide range of causes and is influenced by multiple factors. The primary causes can be congenital, genetic, inflammatory, infectious, anoxic (lack of oxygen), traumatic, and metabolic. The brain injury leading to CP can occur before birth (prenatal), during birth (natal), or after birth (postnatal).²

Key causes and timing

• Prenatal Injury: Accounts for 75-80% of CP cases and includes factors such as genetic issues, infections, and developmental problems in the womb.
• Significant Birth Trauma or Asphyxia: Less than 10% of cases are due to significant complications during birth.

Major risk factors

• Prematurity and Low Birth Weight: The risk of developing CP increases as the gestational age and birth weight decrease. Babies weighing between 500-999 grams at birth have a CP incidence of 10-18%.
• Gestational Age: CP is more common in babies born very prematurely or at full term. Although full-term infants are at lower risk individually, they represent a large proportion of births and, thus, a significant number of CP cases.
• Prenatal Maternal Infections: Conditions like chorioamnionitis (inflammation of the fetal membranes) are significant risk factors, contributing to 12% of CP cases in term infants and 28% in preterm infants.
• Cystic Periventricular Leukomalacia (CPVL): This brain injury is a significant risk factor, with over 60 of infants with CPVL developing CP.

Specific prenatal risk factors

• Intrauterine Infections: Infections contracted while in the womb.
• Teratogenic Exposures: Exposure to substances that cause developmental abnormalities.
• Placental Complications: Problems with the placenta that can affect fetal development.
• Multiple Births: Twins, triplets, and other multiple births have a higher incidence of CP compared to single births.
• Maternal Conditions: Maternal health issues such as mental retardation, seizures, or hyperthyroidism can increase the risk.

Perinatal risk factors

• Infections: Infections contracted around the time of birth.
• Intracranial Hemorrhage: Bleeding in the brain, which can occur during a difficult birth process.^2,3

Symptoms

• Movement Problems: Trouble with reaching, grasping, and walking due to:
  • Spasticity: Stiff and tight muscles
  • Dyskinesia: Uncontrollable movements
  • Hyperreflexia: Overactive reflexes
  • Muscle Coactivation: Opposing muscles working against each other
  • Developmental Reactions: Reflexes that normally disappear as babies grow but persist in CP
  • Musculoskeletal Issues: Abnormal muscle and bone development
  • Defective Programming: Difficulty in coordinating movements
• Muscle Weakness and Tightness: This occurs because:
  • Motor Unit Recruitment: Not enough muscle fibres are activated
  • Mechanical Stresses: Changes in the way forces are applied to muscles
  • Hormonal Factors: Hormones affecting muscle growth and function

Overview of epilepsy

Epilepsy is a brain disorder that causes repeated and unpredictable seizures, which are sudden bursts of abnormal brain activity. It's not just one disease but a group of disorders that all involve some form of brain dysfunction and can have many different causes. A seizure happens when there's a temporary surge of electrical activity in the brain, leading to various signs and symptoms. To be diagnosed with epilepsy, a person must have at least one seizure and a tendency to have more. Epilepsy affects not only the brain but also has cognitive, psychological, and social impacts on a person’s life.⁵

Classification of epilepsy

• Localization-Related Epilepsies: 57 children (22.4%) had this type, where seizures start in a specific area of the brain. This group included 37 cases with known causes and 20 with unknown causes.
• Generalized Epilepsies: 55 children (21.6%) had seizures that affected the whole brain. Among these, seven had inherited types, 46 had known causes, and 2 had unknown causes.
• Undetermined Epilepsies: 33 children (12.9%) couldn't be classified into either of the above categories.
• Special Syndromes: 110 children (43.1%) had special types of epilepsy, mostly febrile convulsions (103 cases), with seven others having different specific types.⁶

Epilepsy in Cerebral Palsy

Overview 

Epilepsy is common in children with cerebral palsy (CP), a condition noted over 100 years ago by Freud. Recent studies emphasise the impact of epilepsy on cognitive function in children with hemiplegic CP, suggesting that even unnoticed seizure activity can worsen cognitive problems. Both motor difficulties and cognitive impairments often stem from the same brain issues that cause epilepsy.⁷

Prevalence 

In the general childhood population, about 3 to 6 out of every 1000 children have epilepsy. However, 15 to 55% of children and adults with CP also have epilepsy. This risk increases to 71% if the child has a learning disability. The likelihood of epilepsy varies with different types of CP:

• Tetra- or triplegic CP: 50% to 94%
• Hemiplegic CP: 33% to 50%
• Spastic or ataxic diplegia: 16% to 27%
• Dystonic/dyskinetic CP: About 25%
• Pure ataxic CP: Rarely associated with epilepsy⁷

Children with CP who have more severe brain involvement are more likely to develop epilepsy.

Risk factors 

Several factors can contribute to the development of both CP and epilepsy:

• Genetic Factors: Families with a history of epilepsy are more likely to have children with both CP and epilepsy.
• Pre- and Perinatal Events: Complications before and around birth, such as brain malformations or lack of oxygen, are significant risk factors.
• Postnatal Causes: Head injuries, infections, and severe lack of oxygen after birth can also lead to CP and epilepsy.

Research shows that in some families, genetic predispositions play a role, making it more likely for epilepsy and CP to occur together.

Diagnosis 

Diagnosing epilepsy in children with CP can be challenging. Seizures may look like other involuntary movements common in CP, such as dystonia or ataxia. Non-epileptic events, like breath-holding spells or fainting, can also confuse the diagnosis.

To accurately diagnose epilepsy, it’s crucial to consider all possible causes of sudden movement or changes in consciousness. Different types of seizures have consistent patterns, and video recordings of seizures can be helpful for diagnosis. However, interpreting EEG results can be difficult because children with CP may show brain activity changes similar to epilepsy, even without actual seizures.

By understanding these complexities, better care and management can be provided for children with CP and epilepsy.^8,9

Managing seizures in cerebral palsy

With CP, the likelihood of seizures recurring is higher. Generally, treatment isn't started after just one seizure unless there's a neurological issue, abnormal EEG, or a progressive neurological disorder. Treatment can halve the risk of future seizures. It's best to keep daily doses to a minimum to improve compliance. Patients should be warned against suddenly stopping their medication, as this can lead to more seizures or even status epilepticus if the drugs are taken inconsistently.

Choice of medication

The principles for selecting antiepileptic drugs (AEDs) in children with CP and epilepsy are similar to those for children with just epilepsy. Factors like seizure type, epilepsy syndrome, age, gender, cost, side effects, interactions with other medications, and additional health issues guide AED selection. About half of the patients will be seizure-free with their first AED. Generally, carbamazepine or lamotrigine is used for focal-onset seizures and valproate for generalised seizures. The chosen drug's dose is gradually increased until seizures are controlled or side effects prevent further increase. If seizures persist at the maximum tolerated dose, a second drug is added, and the first is gradually withdrawn. Most patients with a single seizure type can achieve good control with one AED. However, sometimes more than one drug is needed, but this often increases side effects. Combination therapy should only be tried after at least two single-drug trials have failed. If two drugs don't work, it's considered treatment-resistant epilepsy, and surgery may be necessary.¹¹

Surgical treatment

Surgery may be an option for patients whose seizures don't respond to AEDs. This is most effective with a well-defined seizure focus. Other interventions include severing the corpus callosum or deep-brain stimulation for intractable seizures.

Vagal nerve stimulation

This method has shown some benefit for children with intractable epilepsy and is an option for those who aren't candidates for surgery. Its mechanism is unknown, and side effects include temporary hoarseness during stimulation.

Ketogenic diet

A ketogenic diet can help control difficult-to-manage seizures by maintaining a state of ketosis. This diet can reduce seizure frequency and severity, but it is often hard to follow and may cause side effects like lethargy and gastrointestinal issues.

Bone health in CP with epilepsy

Children with CP and epilepsy are at increased risk for osteoporosis due to limited mobility. Ensuring optimal bone health and screening for fractures are important in these patients.

Prognosis

CP with a high rate of epilepsy often indicates significant brain damage. The prognosis of epilepsy in children depends on the cause and type of epilepsy. Early onset and drug resistance are associated with worse outcomes. Many children with CP and epilepsy achieve good control with the first or second AED, but those who continue to have seizures face more complications. Children with developmental anomalies or infections as the underlying cause of CP and epilepsy generally have a poorer prognosis.

Taking care of kids with CP and epilepsy involves close monitoring, making sure their seizures are under control, and paying attention to their growth and bone health, as some seizure medicines can affect these things. Overall, understanding the relationship between CP and epilepsy helps doctors provide better care for these kids.^10,11

Summary

Cerebral palsy (CP) is a condition caused by brain damage that affects movement and posture, occurring before, during, or shortly after birth. It doesn’t worsen over time. People with CP often have trouble with sensation, thinking, and communication and sometimes experience seizures. CP comes in different types: Quadriplegic CP, which is severe and affects all limbs and the trunk; Hemiplegic CP, which impacts one side of the body more, especially the upper limb; and Diplegic CP, which mainly affects the legs. Causes include genetic issues, infections, lack of oxygen, and birth complications, with higher risks for premature babies, low birth weight, and multiple births. Epilepsy, a condition causing seizures due to abnormal brain activity, is common in children with CP. The risk of epilepsy is higher in children with more severe CP types. Both CP and epilepsy can be linked to genetic factors, birth complications, and injuries after birth. Diagnosing epilepsy in children with CP is tricky because their seizure-like movements might be part of CP. Understanding how CP and epilepsy relate helps doctors provide better treatment and care, improving the quality of life for affected children.