Pediatric Stroke

Definition: A stroke is defined as the sudden onset of a focal neurological deficit lasting > 24 hours (or leading to death) caused by a disturbance in blood supply to the brain.
Pediatric Stroke Classification:
1. Perinatal Stroke: 20 weeks gestation to 28 days of life.
2. Childhood Stroke: > 28 days to 18 years of age.
Types:
- Arterial Ischemic Stroke (AIS): Obstruction of an artery (Commonest).
- Cerebral Sinovenous Thrombosis (CSVT): Thrombosis of venous sinuses.
- Hemorrhagic Stroke: Rupture of a vessel.

Incidence: 2–13 per 100,000 children per year.
Mortality: A top 10 cause of death in children.
Morbidity: > 60% of survivors have permanent neurological deficits (Cerebral Palsy, Epilepsy).

Unlike adults (where atherosclerosis/HTN dominates), pediatric stroke is multifactorial.

Category	Specific Causes / Risk Factors
Arteriopathies (50-80% of AIS)	• Focal Cerebral Arteriopathy (FCA): Transient inflammatory stenosis (often post-Varicella). • Moyamoya Disease: Chronic progressive stenosis of distal ICA. • Arterial Dissection: Post-trauma (even minor neck trauma) or spontaneous. • Vasculitis: PAN, Takayasu, Primary CNS vasculitis.
Cardiac Disorders (25%)	• Congenital Heart Disease: Cyanotic > Acyanotic (R-to-L shunt). • Procedures: Cardiac catheterization, ECMO. • Infection: Infective Endocarditis. • Cardiomyopathy/Arrhythmias.
Hematologic	• Sickle Cell Disease: Highest risk (10% risk without screening). • Prothrombotic States: Protein C/S deficiency, Factor V Leiden, Antithrombin III deficiency. • Iron Deficiency Anemia: Thrombocytosis/hyperviscosity.
Infectious	• Post-Varicella Angiopathy: Stroke 3–12 months after Chickenpox. • Meningitis: Bacterial (Pneumococcal/TB) causing vasculitis. • Head/Neck Infections: Mastoiditis (Risk of CSVT).
Metabolic / Genetic	• Homocystinuria: Thromboembolism. • MELAS: Mitochondrial Encephalomyopathy, Lactic Acidosis, Stroke-like episodes. • Fabry Disease.

Symptoms vary significantly by age.

A. Neonates / Infants

Seizures: Focal clonic seizures are the most common presentation.
Encephalopathy: Lethargy, apnea, poor feeding.
"Handedness": Pathological early handedness (< 1 year) indicates contralateral hemiparesis.

B. Older Children

Seizures (Todd’s Paresis): Post-ictal weakness.
Hemiplegic Migraine: Strong family history; headache follows aura.
Intracranial Infection: Abscess, ADEM (Acute Disseminated Encephalomyelitis).
Metabolic: Hypoglycemia (focal signs possible).
Tumor: Acute hemorrhage into a tumor.

A. Neuroimaging (Stat)

MRI Brain with DWI (Diffusion Weighted Imaging): Gold Standard.
- DWI: Shows restriction (bright) within minutes of ischemia.
- ADC Map: Confirms true restriction (dark).
MRA / MRV (Angiography/Venography): Essential to visualize arteriopathy (Moyamoya, dissection) or sinus thrombosis.
CT Head: Less sensitive for acute ischemia but excellent for Hemorrhage. Used if MRI is unavailable or for rapid exclusion of bleed.

B. Etiological Workup (The "Stroke Protocol")

Cardiac: Echocardiography (Transthoracic/Transesophageal) with bubble study (for PFO). ECG.
Vascular: Carotid Doppler (if dissection suspected).
Blood Work:
- CBC (Sickle cell, Polycythemia, Platelets).
- Coagulation profile (PT/APTT).
- Thrombophilia screen (Protein C, S, AT3, Factor V Leiden, Lipoprotein-a, Homocysteine).
- Inflammatory markers (ESR, CRP, ANA).
- Lipid profile.

Stabilization (ABC):
- Maintain Oxygen saturation > 92%.
- Blood Pressure: Permissive hypertension allowed (to maintain cerebral perfusion). Treat only if >95th percentile + 15-20%.
- Glucose: Treat hypoglycemia immediately. Avoid hyperglycemia (worsens infarct).
- Fever: Aggressive antipyretics (hyperthermia worsens outcome).
- Seizures: Treat aggressively (Benzodiazepines $\to$ Levetiracetam).
Specific Reperfusion Therapy:
- tPA (Tissue Plasminogen Activator): Controversial in children. Not routinely FDA approved. Considered only if:
  - Adolescent / Large child.
  - Within 4.5 hours window.
  - Confirmed large vessel occlusion.
- Mechanical Thrombectomy: Increasing evidence for benefit in older children with large vessel occlusion (LVO) within 24 hours.
Antithrombotic Therapy (Standard of Care):
- Aspirin: (3–5 mg/kg/day). First-line for most Arterial Ischemic Strokes (non-cardioembolic, non-dissection).
- Anticoagulation (LMWH/Unfractionated Heparin):
  - Indicated for Arterial Dissection (extracranial).
  - Indicated for Cardioembolic Stroke.
  - Indicated for Cerebral Sinovenous Thrombosis (CSVT).
  - Contraindication: Hemorrhagic stroke / large infarct with hemorrhagic transformation.

Sickle Cell Disease: Exchange Transfusion to reduce HbS < 30%. Chronic hypertransfusion program thereafter.
Moyamoya Disease: Surgical Revascularization (Pial synangiosis / EDAMS).
Autoimmune/Vasculitis: High-dose Steroids + Cyclophosphamide.

Secondary Prevention: Long-term Aspirin (usually 2 years or lifelong depending on cause).
Rehabilitation: Physical therapy (constraint-induced movement therapy), Occupational therapy, Speech therapy.
Education: Individualized Education Plan (IEP) for cognitive deficits.

Recurrence: 20–30% overall. Highest risk in cases with Arteriopathy (Moyamoya/Vasculitis).
Neurological Outcome:
- Hemiplegic Cerebral Palsy: Most common motor sequela.
- Epilepsy: Develops in 25% of survivors.
- Cognitive: Learning disabilities, ADHD, behavioral issues.
Plasticity: Young brains have higher plasticity, so motor recovery is often better than in adults, but cognitive deficits may emerge years later ("growing into the deficit").