Seizure Disorder, Focal

Seizure Disorder, Focal is a topic covered in the 5-Minute Clinical Consult.

To view the entire topic, please or .

5-Minute Clinical Consult (5MCC) app and website powered by Unbound Medicine helps you diagnose and manage 900+ medical conditions. Exclusive bonus features include Diagnosaurus DDx, 200 pediatrics topics, and medical news feeds. Explore these free sample topics:

-- The first section of this topic is shown below --

Basics

Description

  • Seizures occur when abnormal synchronous neuronal discharges in the brain cause transient cortical dysfunction.
  • Focal or localization-related seizures have previously been referred to as partial seizures and originate from a discrete focus limited to one cerebral hemisphere.
  • Focal seizures are further divided into aware versus unaware and motor versus nonmotor.
  • Presence of impaired awareness is defined as the inability to respond normally to exogenous stimuli due to altered awareness and/or responsiveness:
    • Focal seizures with impairment of awareness (formerly “complex partial seizures”)
    • Focal seizures without impairment of awareness (formerly “simple partial seizures”)

Epidemiology

Prevalence
Focal seizures occur in 20/100,000 persons in the United States.

Etiology and Pathophysiology

  • Focal seizures begin when a localized seizure focus produces an abnormal, synchronized depolarization within a neuronal network limited to one cerebral hemisphere; it may stay discretely localized or be widely distributed throughout that hemisphere.
  • The area of cortex involved in the seizure determines the symptoms; for example, an epileptogenic focus in motor cortex produces contralateral motor symptoms.
  • Most common etiologies vary by life stage:
    • Early childhood: developmental/congenital malformation, trauma
    • Young adults: developmental, infection, trauma
    • Adults 40 to 60 years of age: cerebrovascular insult, infection, trauma
    • Adults >60 years of age: cerebrovascular insult, trauma, neoplasm

Genetics
Benign rolandic epilepsy; has an autosomal dominant inheritance pattern

Risk Factors

  • History of traumatic brain injury (TBI)
  • Thiamine-deficient formula

Commonly Associated Conditions

Depression

-- To view the remaining sections of this topic, please or --

Basics

Description

  • Seizures occur when abnormal synchronous neuronal discharges in the brain cause transient cortical dysfunction.
  • Focal or localization-related seizures have previously been referred to as partial seizures and originate from a discrete focus limited to one cerebral hemisphere.
  • Focal seizures are further divided into aware versus unaware and motor versus nonmotor.
  • Presence of impaired awareness is defined as the inability to respond normally to exogenous stimuli due to altered awareness and/or responsiveness:
    • Focal seizures with impairment of awareness (formerly “complex partial seizures”)
    • Focal seizures without impairment of awareness (formerly “simple partial seizures”)

Epidemiology

Prevalence
Focal seizures occur in 20/100,000 persons in the United States.

Etiology and Pathophysiology

  • Focal seizures begin when a localized seizure focus produces an abnormal, synchronized depolarization within a neuronal network limited to one cerebral hemisphere; it may stay discretely localized or be widely distributed throughout that hemisphere.
  • The area of cortex involved in the seizure determines the symptoms; for example, an epileptogenic focus in motor cortex produces contralateral motor symptoms.
  • Most common etiologies vary by life stage:
    • Early childhood: developmental/congenital malformation, trauma
    • Young adults: developmental, infection, trauma
    • Adults 40 to 60 years of age: cerebrovascular insult, infection, trauma
    • Adults >60 years of age: cerebrovascular insult, trauma, neoplasm

Genetics
Benign rolandic epilepsy; has an autosomal dominant inheritance pattern

Risk Factors

  • History of traumatic brain injury (TBI)
  • Thiamine-deficient formula

Commonly Associated Conditions

Depression

There's more to see -- the rest of this topic is available only to subscribers.