1. Definition and Initial Triage
- Definition: A seizure occurring in the absence of a temporary or reversible precipitating factor (e.g., no fever, no acute head trauma, no metabolic derangement like hypoglycemia/hyponatremia).
- Goal: Determine if it was a true seizure (exclude mimics), assess the risk of recurrence, and decide on pharmacotherapy.
2. Step 1: Diagnostic Evaluation
A. History (Crucial for excluding mimics)
- Differentiate from Syncope: (Pallor vs. Cyanosis; rapid recovery vs. confusion). Syncope is the most common mimic.
- Differentiate from NEAD: (Psychogenic Non-Epileptic Attacks) – closed eyes, asynchronous movements.
- Details: Aura, lateralizing signs, duration, post-ictal state.
B. Physical Examination
- Neurologic: Focal deficits (Todd’s paresis), asymmetry.
- Systemic: Neurocutaneous markers (Café-au-lait spots, hypopigmented macules), signs of head trauma.
C. Investigations
- EEG (Electroencephalogram):
- Standard of Care: Recommended for all patients with a first unprovoked seizure.
- Timing: Ideally within 24–48 hours (highest yield).
- Findings: Epileptiform discharges (spikes/sharp waves) predict recurrence.
- Neuroimaging:
- MRI Brain (Epilepsy Protocol): Gold standard. Essential if the seizure is focal, exam is abnormal, or EEG is non-diagnostic.
- CT Head: Used in emergency (r/o bleed) or if MRI is unavailable/contraindicated. (High yield for calcified granulomas/NCC in developing countries).
- Laboratory: Electrolytes, Glucose, Ca/Mg (to strictly rule out provoked causes), Toxicology screen (if indicated).
3. Step 2: Risk Stratification (Recurrence Risk)
The decision to treat depends on the probability of a second seizure within the next 2 years.
| Risk Factors for Recurrence | Recurrence Rate (2 Years) |
|---|---|
| Normal EEG + Normal MRI + Normal Exam | ~20–25% (Low Risk) |
| Abnormal EEG (Epileptiform) | ~60% (High Risk) |
| Structural Lesion on MRI | >60% (High Risk) |
| Focal Neurologic Deficit | High Risk |
| Seizure during Sleep | High Risk |
| Previous Symptomatic Event | High Risk |
- Note: Overall recurrence risk after any first unprovoked seizure is ~40–50%.
4. Step 3: Treatment Decision (To Start AED or Not?)
Standard Rule: Do NOT routinely start Antiepileptic Drugs (AEDs) after a first unprovoked seizure if the workup is normal.
Indications to Start AED (ILAE Guidelines):
- High Risk of Recurrence (>60%):
- Structural brain lesion (e.g., previous stroke, contusion, cavernoma).
- Unequivocal epileptiform abnormalities on EEG.
- Diagnosis of a specific epilepsy syndrome (e.g., Juvenile Myoclonic Epilepsy).
- Neurologic deficit present from birth (CP, Intellectual Disability).
- Social/Safety Considerations:
- Patient preference (fear of second event).
- Critical professions (machinery, working at heights, driving dependence).
5. Step 4: Choice of Pharmacotherapy (If Indicated)
If the decision is made to treat, monotherapy is preferred.
- Focal Onset: Carbamazepine, Oxcarbazepine, Levetiracetam, Lamotrigine.
- Generalized Onset: Valproate, Levetiracetam, Lamotrigine.
- Unclear/Unclassified: Broad-spectrum agent (Levetiracetam or Valproate). Avoid Carbamazepine if generalized onset is possible.
6. Step 5: Counseling and Lifestyle
- Safety: No driving (per local laws, usually 6–12 months seizure-free), no swimming alone, precautions with heights/fire/machinery.
- Triggers: Avoid sleep deprivation, alcohol, and excessive stress.
- First Aid: Educate family on recovery position; prescribe rescue midazolam only if the first event was Status Epilepticus or remote location.