Partial Seizures

Classification

The following table outlines the features of Partial (Focal) Epilepsy, classified according to the International League Against Epilepsy (ILAE) 2017 guidelines (with previous terminology in parentheses).

Classification	Etiology	Clinical Features	Semiology (Signs & Symptoms)	EEG Features
Focal Aware Seizures (Formerly: Simple Partial Seizures)	Structural: Cortical dysplasia, tumor, vascular malformation, post-stroke gliosis. Genetic: KCNQ2/3 mutations (Benign Familial Neonatal). Infectious: Cysticercosis, tuberculoma. Metabolic: Hypocalcemia, hypoglycemia.	Consciousness: Preserved (Fully aware of self/environment). Duration: Seconds to minutes. Post-ictal: Usually no confusion; immediate return to baseline.	Motor: Clonic jerking (Jacksonian march), tonic posturing, version (head turning). Sensory: Paresthesias, visual flashes, auditory buzzing. Autonomic: Epigastric rising, sweating, flushing, ictal tachycardia. Psychic: Déjà vu, fear, forced thinking.	Interictal: Focal sharp waves or spikes over the affected region (e.g., temporal or frontal leads). Ictal: Rhythmic focal discharge; Note: Surface EEG may be normal in deep/small foci (e.g., frontal lobe).
Focal Impaired Awareness Seizures (Formerly: Complex Partial Seizures)	Mesial Temporal Sclerosis: Most common cause in temporal lobe epilepsy. Limbic System Pathology: Tumors (DNET), gliosis. Infectious: Herpes encephalitis sequelae.	Consciousness: Impaired (Staring, unresponsiveness). Duration: 1–2 minutes. Aura: Often preceded by a focal aware seizure (aura). Post-ictal: Confusion, fatigue, amnesia for event, transient aphasia (if dominant hemisphere).	Automatisms: Oro-alimentary: Lip smacking, chewing, swallowing. Manual: Fumbling, picking at clothes. Ambulatory: Wandering. Motor: Dystonic posturing (contralateral limb).	Interictal: Anterior temporal spikes/sharp waves (temporal lobe); midline/frontal spikes (frontal lobe). Ictal: Rhythmic theta (4–7 Hz) or delta activity, typically evolving in amplitude and frequency.
Focal to Bilateral Tonic-Clonic Seizures (Formerly: Secondarily Generalized)	Progression: spread of discharge from a focal focus to bilateral networks (corpus callosum/thalamocortical).	Consciousness: Initially preserved (aura) then lost. Evolution: Focal onset $\to$ Generalization. Post-ictal: Deep sleep, Todd’s paresis (transient focal weakness).	Onset: Asymmetrical tonic posturing (Figure of 4). Progression: Bilateral symmetric tonic stiffening followed by rhythmic clonic jerking.	Onset: Focal spikes or sharp waves. Progression: Rapid generalization to high-amplitude polyspikes and slow waves obscuring focal onset.

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Treatment of Simple Partial Seizures (Focal Aware Seizures)

1. General Management Principles

• Goal: Complete seizure freedom with no adverse effects.
• Diagnosis Confirmation: Ensure the event is epileptic and not a mimic (e.g., TIA, migraine, psychogenic).
• Initiation: Pharmacotherapy is usually started after the second unprovoked seizure. Treatment after a single seizure is considered if there is a high risk of recurrence (abnormal EEG/MRI, structural lesion).

2. Pharmacotherapy (First-Line Agents)

• Carbamazepine (CBZ): Long-standing first-line agent. Effective for focal seizures.
  • Dose: Start 10–20 mg/kg/day. Monitor for rash (HLA-B*1502 screening in risk populations) and hyponatremia.
• Oxcarbazepine (OXC): Similar efficacy to CBZ with fewer side effects and no auto-induction of metabolism.
  • Dose: 8–10 mg/kg/day starting.
• Levetiracetam (LEV): increasingly preferred due to broad spectrum, rapid titration, and lack of drug interactions.
  • Dose: 10–60 mg/kg/day.
• Lamotrigine (LTG): Effective and well-tolerated but requires slow titration to avoid Stevens-Johnson Syndrome.
  • Usage: Often preferred in women of childbearing age.

3. Alternative and Add-On Therapies

• Second-Line/Adjunctive: Lacosamide, Topiramate, Zonisamide, Valproate.
• Topiramate: Good for comorbidities like migraine or obesity.
• Lacosamide: Sodium channel blocker, available IV/PO, useful for rapid loading.

4. Management of Refractory Cases

• Definition: Failure of two appropriately chosen and tolerated AED schedules.
• Surgical Evaluation: If a structural lesion (e.g., tumor, dysplasia) is identified, resection (lesionectomy) may be curative.
• Neurostimulation: Vagus Nerve Stimulation (VNS) or Responsive Neurostimulation (RNS) for non-surgical candidates.

5. Lifestyle and Education

• Avoid Precipitating Factors: Sleep deprivation, alcohol, stress.
• Safety: Precautions regarding driving, swimming, and heights.

Management of Complex Partial Seizures (Focal Impaired Awareness Seizures)

1. Definition and Goals

• Current Terminology: Classified as Focal Impaired Awareness Seizures (ILAE 2017).
• Goal: Complete seizure freedom with minimal medication side effects (QoL preservation).
• Strategy: Accurate diagnosis $\to$ Monotherapy $\to$ Polytherapy $\to$ Surgical evaluation if refractory.

2. Acute Management (Seizure First Aid)

• Most events are self-limiting (1–2 mins).
• Immediate Care:
  • Ensure safety: Remove dangerous objects, place in lateral decubitus position (recovery position) to prevent aspiration.
  • Do Not: Restrain the patient or insert objects into the mouth.
  • Observation: Note time of onset, automatisms (lip-smacking, wandering), and post-ictal lateralizing signs (e.g., nose wiping, Todd’s palsy).
• Rescue Medication: If seizure lasts >5 minutes (Status Epilepticus protocol):
  • Midazolam: 0.2 mg/kg Intranasal/Buccal/IM.
  • Lorazepam: 0.1 mg/kg IV.

3. Diagnostic Evaluation for Management Planning

• Video EEG: Essential to correlate semiology with electrographic onset (localize focus). Standard EEG detects interictal spikes (anterior temporal/frontal).
• MRI Brain (Epilepsy Protocol): Mandatory to rule out structural lesions.
  • Common substrates: Mesial Temporal Sclerosis (MTS), Focal Cortical Dysplasia (FCD), Low-grade tumors (DNET, Ganglioglioma).

4. Pharmacologic Management (Long-term)

Principles: Start low, go slow. Monotherapy is successful in 50–70% of patients.

• First-Line Agents (Drugs of Choice):

  • Carbamazepine (CBZ): Gold standard for focal seizures.
    • Dose: 10–20 mg/kg/day (Start 5 mg/kg, titrate biweekly).
    • Monitor: CBC (agranulocytosis), Sodium (hyponatremia), HLA-B*1502 (SJS risk).
  • Oxcarbazepine (OXC): Similar efficacy to CBZ, better tolerability, less enzyme induction.
    • Dose: 8–10 mg/kg/day initially.
  • Levetiracetam (LEV): Increasing first-line usage due to safety profile, no drug interactions, and rapid titration.
    • Dose: 20–60 mg/kg/day.

• Second-Line / Adjunctive Agents:

  • Lamotrigine (LTG): Excellent for focal epilepsy; requires slow titration (risk of rash). Preferred in women of childbearing age.
  • Topiramate (TPM): Broad spectrum; caution for cognitive slowing/weight loss.
  • Lacosamide (LCM): Sodium channel blocker; low interaction profile.
  • Valproate (VPA): Broad spectrum; useful if generalized seizure overlap is suspected or diagnosis is unclear.

5. Management of Drug-Resistant (Refractory) Epilepsy

• Definition: Failure of 2 tolerated, appropriately chosen AED schedules (monotherapy or combination).
• Pre-Surgical Evaluation: ~30% of focal epilepsy becomes refractory.
  • Video-EEG telemetry, High-resolution MRI (3T), PET/SPECT scans.
• Surgical Options (Curative):
  • Anterior Temporal Lobectomy: Standard of care for Mesial Temporal Sclerosis (MTS). 60–80% seizure freedom rate (higher than medication alone).
  • Lesionectomy: For discrete tumors or dysplasia.
• Palliative Procedures (Non-resective):
  • Vagus Nerve Stimulation (VNS): For non-surgical candidates.
  • Responsive Neurostimulation (RNS): Closed-loop stimulation for seizure abortion.
  • Ketogenic Diet: Adjunct in children with refractory epilepsy.