What are the possible diagnoses and investigations for a 2-year-old child with left hemiparesis and left foot drop since birth?

Congenital Left Hemiparesis with Foot Drop in a 2-Year-Old

Primary Diagnosis

The most likely diagnosis is unilateral spastic cerebral palsy (hemiplegic CP), which accounts for 38% of all CP cases and typically presents with congenital hemiparesis and foot drop. 1

Differential Diagnoses to Consider

• Perinatal arterial infarction (most common in term infants, accounting for 30% of congenital hemiparesis cases, particularly associated with right-sided weakness) 2
• Periventricular white matter lesions (if the child was born preterm, this accounts for 71% of cases in that population) 2
• Brain malformations including polymicrogyria, heterotopia, or schizencephaly (present in 18% of congenital hemiparesis cases) 2
• Unilateral grade IV hemorrhage or perinatal arterial ischemic stroke (these unilateral lesions typically result in ambulant CP) 1

Essential Investigations

Neuroimaging (First Priority)

MRI brain is the single most critical investigation and should be performed immediately, as it has 86-89% sensitivity for detecting CP and provides both diagnostic and prognostic information. 1

• MRI findings guide prognosis: Unilateral lesions (grade IV hemorrhage or perinatal arterial ischemic stroke) predict ambulant CP, while bilateral lesions predict non-ambulant outcomes 1
• Important caveat: 18% of infants with congenital hemiparesis have normal neuroimaging, and these children are significantly more likely to outgrow all signs of hemiparesis by age 3 (29% vs 0% with abnormal imaging) 2
• If initial MRI at this age shows subtle findings: Repeat MRI may be needed, as subtle white matter lesions can be difficult to detect due to rapid growth, myelination, and activity-dependent plasticity 1

Standardized Neurological Assessment

The Hammersmith Infant Neurological Examination (HINE) should be performed immediately, as it has 90% predictive value for CP at ages 2-24 months. 1

• HINE score interpretation at this age:
  • Score 50-73: Indicates likely unilateral CP (95-99% will walk) 1
  • Score <50: Indicates likely bilateral CP 1
  • Score <73: Indicates high risk of CP 1
  • Score <40: Indicates abnormal outcome, usually CP 1

Standardized Motor Assessment

The Developmental Assessment of Young Children (DAYC) should be administered, as it has 89% predictive value for CP and quantifies motor delay. 1

• Alternative assessments include the Alberta Infant Motor Scale (AIMS) with 86% predictive value, or the Movement Assessment of Infants (MAI) with 73% predictive value 1

Clinical History Details to Elicit

• Perinatal risk factors: Conception, pregnancy, birth complications, and postneonatal period events (the complete causal path is unclear in 80% of cases, but risk factors are often identifiable) 1
• Gestational age at birth: Preterm infants have different neuroimaging patterns (periventricular white matter lesions predominate) 2
• Side of weakness: Right-sided hemiparesis has 4.6 times higher risk of perinatal arterial infarction 2
• Severity of weakness: Moderate to severe weakness has 4.4 times higher risk of perinatal arterial infarction 2
• Early motor milestones: Hand asymmetry is an early observable sign, with reduced voluntary movements and functional abilities in sitting, grasping, and reaching 3

Associated Impairments to Screen For

The diagnosis of CP or high risk of CP must always include screening for common comorbidities, as these significantly impact quality of life and require early intervention. 1, 4

• Vision assessment: Should have been performed in first 48 hours of life; if abnormal at term-equivalent age, requires vision intervention and reassessment at 3 months (functional blindness affects 11% of CP cases) 1, 4
• Hearing screening: Standard early hearing accommodations needed (hearing impairment affects 4% of CP cases) 1, 4
• Hip surveillance: Begin anteroposterior pelvic radiographs every 6-12 months starting at age 12 months, as hip displacement occurs in 28% of CP cases 3, 4
• Epilepsy screening: Affects 35% of CP cases 1, 5
• Sleep disorders: Affect 23% of CP cases and require early treatment before secondary problems emerge 4
• Feeding/swallowing assessment: If any concerns or history of pneumonia, as pneumonia is the leading cause of death in CP 4

Immediate Management Priorities

Early intervention must begin immediately upon diagnosis or suspicion, as delaying intervention causes harmful, progressively irreversible modifications to muscle and bone growth. 4

Motor Interventions

• Constraint-Induced Movement Therapy (CIMT) should be started immediately for this unilateral CP, as early interventions differ for unilateral versus bilateral CP 1, 3
• Task-specific motor training at home (GAME) produces better motor and cognitive skills at 1 year compared to usual care 3

Orthotic Management

• Ankle-foot orthosis (AFO) should be prescribed immediately for the foot drop to improve gait mechanics, prevent contractures, and enhance mobility 3, 6

Family Support

• Immediate counseling and goal-setting with parents reduces depression and anger, as prolonged diagnostic uncertainty increases depression risk 3
• Screen parental mental health and provide attachment support 3