What is the lifetime risk of seizure in the general population?

Lifetime Risk of Seizure

Approximately 10% of the general population will experience at least one seizure during their lifetime. 1

Epidemiology of Seizures in the General Population

• The lifetime risk of experiencing at least one seizure is estimated to be 10% of the general population, according to the American College of Radiology 1
• More conservative estimates suggest that 2-5% of the population will have at least one nonfebrile seizure during their lifetime 1
• A population-based study in Rochester, Minnesota calculated that 1 in 26 people (approximately 3.9%) will develop epilepsy during their lifetime 2
• The cumulative lifetime risk for any unprovoked seizure is approximately 4.1% in industrialized countries 3

Risk Factors Affecting Seizure Likelihood

• Gender differences exist in seizure risk:

  • Males have a marginally higher incidence of epilepsy and unprovoked seizures compared to females 3
  • This difference is attributed to males' greater exposure to risk factors for lesional epilepsy and acute symptomatic seizures 3
  • However, idiopathic generalized epilepsies (15-20% of all epilepsies) are more common among females 3

• Age-related considerations:

  • Seizure risk varies by age, with higher incidence in early childhood and in older adults 2
  • Lifetime risk was calculated as 1.6% to age 50 and increases to 3.0% by age 80 2
  • When not accounting for competing risk of death (cumulative incidence), the risk is 1.7% to age 50 and 3.4% to age 80 2

Types of Seizures and Their Prevalence

• Seizures can be categorized as:

  • Provoked seizures: occurring due to acute illness, metabolic derangements, or brain injury 4
  • Unprovoked seizures: spontaneous seizures that may indicate epilepsy 4

• Epilepsy (recurrent unprovoked seizures) affects approximately:

  • 1-3% of the general population 4
  • 2.5 million people in the United States (prevalence of about 6.6 per 1,000) 1

• Status epilepticus:

  • Occurs in approximately 50,000 to 150,000 patients per year in the United States 1
  • About 7% of seizure patients presenting to emergency departments have status epilepticus 5
  • Has a mortality rate ranging from 5-22%, and up to 65% in cases refractory to first-line therapies 1

Clinical Implications

• Only about 2-3% of people who experience a single seizure go on to develop epilepsy 6

• Seizures account for approximately 1% of all emergency department visits and 3% of prehospital transports 5

• Common causes of seizures in adults presenting to emergency departments include:

  • Alcoholism
  • Stroke
  • Tumor
  • Trauma
  • Central nervous system infection 5

• The lifetime risk of developing epilepsy has increased over time:

  • From 3.5% in 1960-1969 to 4.2% in 1970-1979 2
  • This trend suggests the importance of continued monitoring of seizure epidemiology

Pitfalls and Caveats

• Many sudden events can be confused with seizures, including:

  • Pseudoseizures
  • Syncope
  • Migraine
  • Cerebrovascular disease
  • Movement disorders
  • Sleep disorders 4

• Careful history, physical examination, EEG, and neuroimaging are essential to distinguish true seizures from seizure mimics 4, 6

• The risk of seizure recurrence must be carefully assessed before initiating antiepileptic drug therapy, as not all patients who experience a single seizure require treatment 4