Epidemiology
Etiology
Etiologies are broadly categorized as provoked (acute symptomatic) or unprovoked (related to a static or progressive underlying condition).
Common Causes (VITAMINS mnemonic):
- Vascular: Stroke (ischemic or hemorrhagic) is the most common cause in adults, especially the elderly. AVMs.
- Infection: Meningitis, encephalitis, brain abscess, neurocysticercosis (most common cause worldwide).
- Trauma: TBI can cause acute seizures or lead to post-traumatic epilepsy.
- Autoimmune: e.g., Anti-NMDA receptor encephalitis, lupus cerebritis.
- Metabolic: Hypoglycemia, hyponatremia, hypocalcemia, uremia, hepatic encephalopathy.
- Idiopathic/Genetic: Significant portion of childhood-onset epilepsies. Examples include juvenile myoclonic epilepsy, childhood absence epilepsy.
- Neoplasms: Primary or metastatic brain tumors. Seizures can be the presenting symptom.
- Substances:
- Withdrawal: Alcohol, benzodiazepines, barbiturates.
- Toxicity/Overdose: Cocaine, amphetamines, TCAs, bupropion, tramadol, theophylline.
Etiology by Age
- Neonates (<1 mo): Hypoxic-ischemic encephalopathy (HIE), intracranial hemorrhage, CNS infection, metabolic disturbances (hypoglycemia, hypocalcemia), congenital brain malformations.
- Infants/Children (1 mo - 12 yr): Febrile seizures (most common), genetic epilepsy, CNS infections, trauma, developmental disorders.
- Adolescents (12 - 18 yr): Trauma, genetic epilepsy (e.g., JME), infection, illicit drug use, brain tumors.
- Young Adults (18 - 35 yr): Trauma, alcohol withdrawal, illicit drug use, brain tumors.
- Older Adults (>35 yr): Cerebrovascular disease (stroke), brain tumors, alcohol withdrawal, metabolic disorders (e.g., hypoglycemia).
Seizure Classification
1. Focal (Partial) Onset Seizures
- Originate in one hemisphere of the brain.
- Focal Aware (Simple Partial): Consciousness is fully maintained. Symptoms vary by the affected lobe (e.g., motor, sensory, autonomic, or psychic symptoms like déjà vu). No postictal state.
- Focal Impaired Awareness (Complex Partial): Consciousness is impaired or lost. Often associated with automatisms (e.g., lip-smacking, chewing, hand-wringing). A postictal state (confusion, lethargy) is common. Most commonly arise from the temporal lobe.
- Focal to Bilateral Tonic-Clonic: Starts as a focal seizure and then spreads to involve both hemispheres, becoming a generalized tonic-clonic seizure.
2. Generalized Onset Seizures
- Originate in and rapidly engage bilateral brain networks.
- Tonic-Clonic (Grand Mal): Abrupt loss of consciousness. Tonic phase = stiffening of the body. Clonic phase = rhythmic jerking of limbs. Often with tongue biting, incontinence. Followed by a significant postictal state.
- Absence (Petit Mal): Brief lapse of consciousness (“staring spell”) for 5-10 seconds, often without loss of postural tone. May have subtle motor signs like eyelid fluttering or lip-smacking. No postictal confusion; patient returns immediately to baseline. Classic in children.
- Myoclonic: Sudden, brief, shock-like muscle jerks. Consciousness is usually preserved.
- Atonic: Sudden loss of muscle tone, leading to “drop attacks” and potential injury.
- Tonic: Sustained muscle stiffening without a clonic phase.
| Feature | Absence (Petit Mal) | Focal Impaired Awareness (Complex Partial) |
|---|---|---|
| Patient Age | Child | Usually Adult |
| Key Event | Brief “staring spell" | "Staring spell” + Automatisms (lip-smacking, fumbling) |
| Postictal State | None. Immediately alert. | Present. Confused & drowsy for minutes after. |
| Aura | No | Yes (common; e.g., déjà vu, odd smell, fear) |
| Duration | Short (< 15 seconds) | Longer (1-2 minutes) |
| EEG | Generalized 3 Hz spike-wave | Focal spikes (e.g., temporal lobe) |
| 1st Line Tx | Ethosuximide | Lamotrigine, Levetiracetam |
Clinical features
Diagnostics
Treatment
Acute management
- Early status epilepticus (5–20 minutes): first-line therapy
- IV benzodiazepine (lorazepam OR diazepam)
- Persistent status epilepticus (20–40 minutes): second-line therapy
- IV fosphenytoin
- IV valproic acid
- IV levetiracetam
- Refractory status epilepticus (40–60 minutes)
- Options include repeat second-line therapy or induction of coma (e.g., with IV propofol, thiopental, midazolam, or pentobarbital).