What are the causes and management of cerebral palsy?

Causes and Management of Cerebral Palsy

Cerebral palsy (CP) is caused by non-progressive disturbances to the developing fetal or infant brain, with approximately 80% of cases having unclear complete causal pathways despite identifiable risk factors across preconception, prenatal, perinatal, and postnatal periods. 1

Definition and Epidemiology

• CP is defined as "a group of permanent disorders of the development of movement and posture, causing activity limitation, that are attributed to non-progressive disturbances that occurred in the developing fetal or infant brain" 1
• It is the most common physical disability in childhood, with a prevalence of 2.1 cases per 1000 in high-income countries 1
• Prevalence is declining in Australia and Europe but appears higher in low to middle-income countries due to greater infectious disease burden and differences in prenatal and perinatal care 1

Causes and Risk Factors

Prenatal Risk Factors

• Genetic factors: Recent evidence suggests 14% of cases have a genetic component 1, 2
• Maternal conditions: Thyroid disease, preeclampsia, infections 1
• Pregnancy complications: Intrauterine growth restriction, multiple gestation 1, 3
• Preconception risks: History of stillbirths, miscarriages, low socioeconomic status, assisted reproduction, and abnormal genetic copy number variations 1

Perinatal Risk Factors

• Prematurity: Children born with body weight below 1500g have 70 times higher risk 4
• Birth complications: Perinatal asphyxia (accounts for only 6-10% of CP in full-term infants) 5
• Periventricular leukomalacia: Associated with 30-50% of CP in premature births 5

Postnatal Risk Factors

• Infections, trauma, stroke, and hypoxic events occurring in early infancy 1

Neuroimaging Findings

The most predictive MRI patterns for CP include:

• White matter injury (cystic periventricular leukomalacia or periventricular hemorrhagic infarctions) (56%) 1
• Cortical and deep gray matter lesions (basal ganglia or thalamus lesions, watershed injury, multicystic encephalomalacia, or stroke) (18%) 1
• Brain maldevelopments (lissencephaly, pachygyria, cortical dysplasia, polymicrogyria, or schizencephaly) (9%) 1

Clinical Presentation and Classification

Motor Types

• Spasticity (85%-91%) 1
• Dyskinesia (4%-7%), including dystonia and athetosis 1
• Ataxia (4%-6%) 1
• Hypotonia (2%) 1

Topographical Distribution

• Unilateral (hemiplegia) (38%) 1
• Bilateral, including:
  • Diplegia (lower limbs affected more than upper limbs) (37%) 1
  • Quadriplegia (all 4 limbs and trunk affected) (24%) 1

Common Comorbidities

• Chronic pain (75%) 1
• Epilepsy (35%) 1
• Intellectual disability (49%) 1
• Musculoskeletal problems (e.g., hip displacement) (28%) 1
• Behavioral disorders (26%) 1
• Sleep disorders (23%) 1
• Visual impairment (11%) 1
• Hearing impairment (4%) 1

Early Diagnosis

Before 5 Months' Corrected Age

The most predictive tools for detecting CP risk are:

• Term-age MRI (86%-89% sensitivity) 1
• Prechtl Qualitative Assessment of General Movements (98% sensitivity) 1
• Hammersmith Infant Neurological Examination (90% sensitivity) 1

After 5 Months' Corrected Age

The most predictive tools are:

• MRI (86%-89% sensitivity) 1
• Hammersmith Infant Neurological Examination (90% sensitivity) 1
• Developmental Assessment of Young Children (83% C index) 1

Management Approach

Early Intervention

• Early diagnosis and prompt referral to diagnostic-specific intervention is essential to optimize infant motor and cognitive plasticity, prevent secondary complications, and enhance caregiver well-being 1
• Early intervention should begin as soon as CP is suspected rather than waiting for definitive diagnosis 1

Red Flags Requiring Prompt Referral

• Loss of motor milestones (suggestive of neurodegenerative process) 1
• Respiratory insufficiency with generalized weakness 1
• Abnormalities on brain MRI 1
• Motor delays present during minor acute illness 1

Treatment Options

• Spasticity management: Botulinum toxin therapies and surgical techniques such as rhizotomy 4
• Multidisciplinary approach including physical therapy, occupational therapy, speech therapy, and medical management 4
• Regular monitoring for comorbidities, especially epilepsy, visual and hearing impairments 1, 4

Prognosis

In high-income countries:

• 2 in 3 individuals with CP will walk 1
• 3 in 4 will talk 1
• 1 in 2 will have normal intelligence 1

Clinical Pearls

• The complete causal pathway to CP remains unclear in approximately 80% of cases, but risk factors are often identifiable through detailed history taking 1
• Early diagnosis does not preclude further etiological investigation, and identifying a specific etiology does not exclude a CP diagnosis 1
• In milder presentations, especially unilateral CP, an infant may score within normal range on standardized motor assessments while still displaying abnormal movements (e.g., completing tasks one-handed) 1
• Assessment should be conducted by professionals skilled at determining atypical movement from variation in typical movement 1
• Severity classification is difficult before age 2 years as almost half of infants have their Gross Motor Function Classification System reclassified 1