Description

• Seizure: sudden and transient symptoms (altered level of consciousness, motor manifestations) due to abnormal neuronal electrical activity in the brain
• Epilepsy: two or more unprovoked seizures apart in a >24-hour period or one unprovoked seizure with a risk of further seizures that is similar to the risk after two unprovoked seizures (at least 60%)
• Status epilepticus: an epileptic seizure that lasts >5 minutes or multiple seizures without returning to normal between them; classifications: generalized, simple and complex partial, absence, nonconvulsive; based on three key features:
  • Seizure origin: focal (previously partial), focal to bilateral, generalized
  • Awareness: aware, focal impaired, or generalized
  • Clinical features: motor, nonmotor (absence, behavior, cognitive, autonomic)
• System(s) affected: nervous
• Synonym(s): convulsion, attacks, spells

Epidemiology

Incidence
200,000 new cases of epilepsy are diagnosed in the United States annually with 45,000 new cases in children <15 years of age.

Prevalence
In 2015, 1.2% of the total U.S. population had active epilepsy.

Etiology and Pathophysiology

• Synchronous and excessive firing of neurons, resulting in an imbalance of regulatory mechanisms in favor of excitatory activity
• Acute symptomatic seizures: triggered by an acute insult to the brain, medical illness, metabolic disturbance, substance/medication ingestion, or withdrawal (such seizures do not necessarily define the presence of epilepsy)
  • Stroke, subdural hematoma, subarachnoid bleed, traumatic brain injury, hypoxic-ischemic injury, acute infection
  • Metabolic and endocrine disorders, drug intoxication/poisoning/overdose
  • Medications: opioids, anticancer drugs, various antibiotics, hypoglycemic agents, immunosuppressants, psychotropic medications, and decongestants
• Vascular malformations
• Familial/genetic seizure syndromes
• Benign neonatal seizures, benign familial neonatal epilepsy, EME, Ohtahara syndrome
• Infancy (age <2 years): febrile seizures, metabolic causes (e.g., hypoglycemia, vitamin B₆ deficiency)
• Childhood (age 2 to 10 years): absence or febrile seizure
• Adolescent (age 10 to 18 years): AV malformation
• Late adulthood (age >60 years); stroke, metabolic disturbances (hypoglycemia, uremia, hepatic failure, electrolyte abnormality), and drugs

Genetics
Family history increases risk by 3-fold.

Risk Factors

History of congenital brain malformations, CNS infections, head trauma, stroke, tumors

General Prevention

Prevent head injuries. Avoid sleep deprivation, excessive alcohol intake, and dehydration.

Commonly Associated Conditions

Genetic syndromes (Angelman, tuberous sclerosis, Sturge-Weber), infections, tumors, drug abuse, alcohol and drug withdrawal, trauma, metabolic disorders, and hormonal changes related to menstrual cycle