Makindo Medical Notes

Related Subjects: |Status Epilepticus (Epilepsy) |Coma management |Lorazepam |Phenytoin |Levetiracetam |Epilepsy - General Management |First Seizure |Epilepsy in Pregnancy |Febrile seizures

Introduction

Post-Stroke Epilepsy (PSE) refers to recurrent seizures occurring after a cerebrovascular event, either ischemic or hemorrhagic stroke. It is a significant complication that can adversely affect recovery, rehabilitation, and quality of life in stroke survivors. PSE encompasses seizures that occur beyond the acute phase of stroke (after one week), distinguishing it from acute symptomatic seizures that happen immediately following the stroke.

Epidemiology

The incidence of PSE varies widely in the literature, with estimates ranging from 2% to 20% among stroke survivors. Factors influencing this variability include differences in study populations, stroke types, and follow-up durations.

• Overall Incidence: Approximately 5-15% of stroke patients develop epilepsy within five years post-stroke.
• Type of Stroke:
  • Ischemic Stroke: PSE occurs in about 2-14% of patients.
  • Hemorrhagic Stroke: Higher incidence, with 10-20% developing PSE.
• Time of Onset:
  • Early seizures (within 7 days): Occur in approximately 3-6% of patients.
  • Late seizures (after 7 days): Represent true epilepsy and occur in 1-4% of patients.

Risk Factors

• Stroke Severity: Larger infarct size and more severe neurological deficits correlate with higher risk.
• Cortical Involvement: Strokes affecting the cerebral cortex, especially the parietotemporal regions, are more epileptogenic than subcortical strokes.
  • Involvement of the supramarginal gyrus and superior temporal gyrus is particularly associated with PSE.
• Hemorrhagic Stroke: Intracerebral hemorrhages have a higher risk due to blood's irritative effects on brain tissue.
• Early Seizures: Patients who experience seizures within the first week post-stroke are at increased risk of developing PSE.
• Hemorrhagic Transformation: Conversion of an ischemic stroke to hemorrhagic increases seizure risk.
• Age: Younger patients (<65 years) may have a higher risk, possibly due to better survival and longer observation periods.
• Cortical Malformations or Pre-existing Lesions: Increase susceptibility to seizures post-stroke.
• Stroke Location: Strokes involving the temporal lobe can lead to temporal lobe epilepsy, even if subcortical.

Pathophysiology not fully understood but may involve:

• Glial Scarring: Formation of gliotic tissue post-injury can alter neuronal excitability.
• Neuronal Hyperexcitability: Changes in neurotransmitter balance, receptor function, and ion channel activity.
• Blood Products: Deposition of iron and other blood breakdown products in hemorrhagic strokes can be epileptogenic.
• Inflammation: Post-stroke inflammatory responses may contribute to seizure development.

Clinical Presentation: Seizures can vary in type and presentation:

• Focal Seizures: Most common type, reflecting the localized brain injury.
  • With Impaired Awareness: May involve automatisms, altered consciousness.
  • Without Impaired Awareness: Motor or sensory symptoms without loss of consciousness.
• Secondary Generalization: Focal seizures may progress to generalized tonic-clonic seizures.
• Status Epilepticus: Rare but serious; prolonged or repetitive seizures without recovery between them.
• Seizure Timing: PSE seizures occur after the acute stroke phase (beyond 7 days) and can emerge months to years post-stroke.

Differential Diagnosis

• Transient Ischemic Attack (TIA): Sudden neurological deficits resolving within 24 hours.
• Recurrent Stroke: New vascular events causing neurological symptoms.
• Metabolic Disturbances: Hyponatremia, hypoglycemia can precipitate seizures or mimic them.
• Infections: Central nervous system infections or systemic infections lowering seizure threshold.
• Medication Side Effects: Certain drugs may induce seizures or cause symptoms resembling them.
• Alcohol Withdrawal: Can cause seizures, particularly in patients with a history of heavy alcohol use.
• Movement Disorders: Hemichorea or other hyperkinetic movements may be mistaken for seizures.

Investigations

• Laboratory Tests:
  • Complete Blood Count (CBC): To detect infections or anemia.
  • Electrolytes: Assess for hyponatremia, hypocalcaemia, or other electrolyte imbalances.
  • Liver and Renal Function Tests: Evaluate for organ dysfunction affecting drug metabolism.
  • Blood Glucose Levels: Hypoglycemia or hyperglycemia can precipitate seizures.
• Imaging Studies:
  • Computed Tomography (CT) Scan: Quick assessment to rule out hemorrhage or new lesions.
  • Magnetic Resonance Imaging (MRI): More sensitive in detecting cortical lesions, infarcts, or gliosis.
• Electroencephalography (EEG):
  • May show focal epileptiform discharges corresponding to the affected hemisphere.
  • Findings can include focal slowing, sharp waves, or spikes.
  • Helps differentiate seizures from other conditions.
• Chest X-Ray: To detect infections, aspiration pneumonia, or cardiac abnormalities.
• Cardiac Evaluation: ECG and echocardiography if cardiac arrhythmias or embolic sources are suspected.

Acute Management

• Seizure Control:
  • Ensure patient safety during seizures (e.g., protect from injury, maintain airway).
  • Administer benzodiazepines (e.g., lorazepam) for prolonged seizures or status epilepticus.
• Treat Underlying Causes:
  • Correct metabolic disturbances (e.g., electrolyte imbalances, hypoglycemia).
  • Treat infections promptly.
  • Review medications that may lower seizure threshold.

Long-Term Management

• Antiepileptic Drugs (AEDs):
  • First-Line Agents: Levetiracetam and lamotrigine are often preferred due to favorable side effect profiles and minimal drug interactions.
  • Alternative Agents: Valproate, carbamazepine, and phenytoin may be used but require careful monitoring.
  • Dosing Considerations: Start with low doses and titrate slowly, considering the patient's renal and hepatic function.
  • Drug Interactions: Be cautious of interactions with anticoagulants and other medications commonly used in stroke patients.
• Monitoring:
  • Regular follow-up to assess seizure control and medication side effects.
  • Blood tests to monitor drug levels (if applicable) and organ function.
• Rehabilitation Support:
  • Physical therapy to maximize functional recovery.
  • Occupational therapy for activities of daily living.
  • Speech and language therapy if aphasia is present.
• Patient Education:
  • Inform about seizure triggers and adherence to medication.
  • Discuss safety measures (e.g., avoiding swimming alone, precautions during bathing).
  • Provide guidance on lifestyle modifications (e.g., alcohol avoidance, sleep hygiene).
• Driving and Legal Considerations:
  • Advise patients to refrain from driving and operating heavy machinery according to local regulations.
  • Provide documentation for driver's license authorities if required.

Prognosis

The prognosis for patients with PSE varies:

• Seizure Control: Many patients achieve good seizure control with appropriate AED therapy.
• Impact on Recovery: Seizures may negatively affect rehabilitation and recovery due to additional neurological damage or medication side effects.
• Quality of Life: PSE can lead to psychological distress, social limitations, and reduced independence.
• Risk of Recurrence: The risk of recurrent seizures is higher in patients with early seizures, cortical involvement, and severe strokes.
• Morbidity and Mortality: Increased risk due to potential for status epilepticus, aspiration pneumonia, and injuries during seizures.

Conclusion

Post-stroke epilepsy is a significant complication that requires prompt recognition and management. A multidisciplinary approach involving neurologists, rehabilitation specialists, and primary care providers is essential to optimize outcomes. Ongoing research aims to better understand the mechanisms underlying PSE and develop preventive strategies.

References

• Haapaniemi E, Strbian D, Rossi C, et al. Acute seizures after intracerebral hemorrhage. Neurology. 2014;83(16):1314-1319.
• Hesdorffer DC, Benn EKT, Cascino GD, Hauser WA. Is a first acute symptomatic seizure epilepsy? Epilepsia. 2009;50(5):1102-1108.
• Silverman IE, Restrepo L, Mathews GC. Poststroke seizures. Arch Neurol. 2002;59(2):195-201.
• Procaccianti G, Zaniboni A, Rondelli F, et al. Seizures in acute stroke: incidence, risk factors and prognosis. Neuroepidemiology. 2012;39(1):45-50.
• Beghi E, D'Alessandro R, Beretta S, et al. Incidence and predictors of acute symptomatic seizures after stroke. Neurology. 2011;77(20):1785-1793.
• International League Against Epilepsy (ILAE). Definition of Epilepsy 2014. Available from: [ILAE Website](https://www.ilae.org/guidelines/definition-and-classification/definition-of-epilepsy-2014).