Epilepsy & Seizure Disorders
A brain disorder causing unprovoked, recurrent seizures due to abnormal electrical activity in the brain.
Emergency Management: Status Epilepticus: Treat emergently with IV Lorazepam 4 mg, followed by a loading dose of Fosphenytoin, Levetiracetam, or Valproate.
Epilepsy is a chronic neurological disorder characterized by an enduring predisposition to generate epileptic seizures. A seizure is a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.
Detailed Overview
Epilepsy is classified by seizure type (focal vs. generalized) and etiology (structural, genetic, infectious, metabolic, immune, or unknown). The condition imposes a heavy burden due to the unpredictability of seizures, risk of bodily injury, and psychosocial stigma. Accurate diagnosis with EEG and imaging is essential to select the correct anti-seizure medication (ASM).
Epidemiology & Demographics
Affects ~1% of the global population. Bimodal age distribution: peaks in early childhood (genetic/developmental causes) and older adults >65 years (stroke/tumors).
Etiological Mechanism
In children: genetic mutations (e.g., SCN1A in Dravet syndrome), cortical dysplasia, hypoxic-ischemic encephalopathy. In adults: ischemic stroke, traumatic brain injury, CNS tumors, CNS infections (neurocysticercosis, HSV encephalitis).
Primary Causes
Mesial temporal sclerosis, prior stroke, glioblastoma, viral encephalitis, genetic channelopathies.
Epileptogenesis occurs when the delicate balance between excitatory (Glutamate) and inhibitory (GABA) neurotransmission in the cortex is disrupted. This can result from altered ion channel function (e.g., mutated voltage-gated sodium channels causing prolonged depolarization), loss of inhibitory interneurons following a brain injury, or aberrant synaptic reorganization (e.g., mossy fiber sprouting in the hippocampus). A seizure initiates when a group of hyperexcitable neurons (seizure focus) fire synchronously in high-frequency bursts (paroxysmal depolarizing shift). If this local discharge overcomes surround inhibition, it propagates via cortical networks to cause a focal seizure, or spreads rapidly to both hemispheres (via thalamocortical pathways) resulting in a generalized seizure.
Diagnostic Criteria & Guidelines
At least two unprovoked seizures occurring >24 hours apart; OR one unprovoked seizure with a probability of further seizures >60% over 10 years (e.g., structural lesion on MRI or epileptiform discharges on EEG); OR diagnosis of an epilepsy syndrome.
Focal seizures: Levetiracetam (500 mg PO BID, titrate up), Lamotrigine, or Carbamazepine. Generalized seizures: Valproic Acid (avoid in women of childbearing potential), Levetiracetam, or Topiramate. Absence seizures: Ethosuximide.
Second-Line & Adjunctive Therapy
Add-on therapy for drug-resistant cases: Lacosamide, Clobazam, Brivaracetam, or Perampanel. Ketogenic diet (primarily in children).
Surgical & Procedural Management
For focal, drug-resistant epilepsy: Surgical resection of the seizure focus (e.g., anterior temporal lobectomy, highly curative). Neuromodulation: Vagus Nerve Stimulation (VNS), Responsive Neurostimulation (RNS), or Deep Brain Stimulation (DBS).
Patient Counseling & Advice
Educate family on seizure first aid: gently roll patient on their side, cushion the head, do not put anything in the mouth, and time the seizure. Call 911 if it lasts > 5 minutes.
Follow-Up & Monitoring Schedule
Regular neurology visits. Monitor ASM levels (e.g., for Phenytoin, Valproate) and check CBC/LFTs for specific drug toxicities.
Preventive Strategies
Prevention of traumatic brain injury (helmets, seatbelts). Good prenatal and perinatal care.
About 60-70% of patients achieve seizure freedom with the first or second ASM. 30% develop drug-resistant epilepsy.