Seizure Disorders

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Basics

Description

  • Seizure: sudden and transient symptoms (altered level of consciousness, motor manifestations) due to abnormal neuronal electrical activity
  • Epilepsy: enduring preposition to generate epileptic seizures; defined as 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: epileptic seizure that lasts >5 minutes or multiple seizures without returning to normal between them. Classification: generalized, simple and complex partial, absence, nonconvulsive; based on three key features:
    • 1) Seizure origin: focal (previously partial), focal to bilateral, generalized
    • 2) Awareness: aware, focal impaired or generalized awareness
    • 3) Clinical features: motor, nonmotor (absence, behavior, cognitive, autonomic)
  • System(s) affected: nervous
  • Synonym(s): convulsion; attacks; spells

Pediatric Considerations
Sedation of the infant should be monitored.

Pregnancy Considerations

  • Preconception: Certain antiepileptic drug (AED) (P450 inducers) may cause hormonal contraceptive failure.
  • Pregnancy: Avoid valproate as possible, due to increased teratogenicity and poor developmental outcomes. During pregnancy, monitor AED levels every trimester for dose adjustment, continue folic acid supplementation, and screen for congenital abnormalities.
  • Levetiracetam, topiramate, lamotrigine are alternatives for women of childbearing potential (1).

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
326,000 children (≤14 years of age) and 600,000 adults (>65 years of age) have a seizure disorder.

Etiology and Pathophysiology

  • Synchronous and excessive firing of neurons, resulting in an imbalance of regulatory mechanisms in favor of excitatory activity. Seizures may be triggered by metabolic/medical conditions, but such seizures do not necessarily define the presence of epilepsy.
  • Acute symptomatic seizures: acute insult to the brain, medical illness, metabolic disturbance, substance/medication ingestion or withdrawal
    • Stroke, subdural hematoma, subarachnoid bleed, traumatic brain injury, hypoxic-ischemic injury
    • Acute infection: brain abscess, meningitis/encephalitis
    • Metabolic and endocrine disorders: hypo-/hyperglycemia, hyponatremia, hypocalcemia, hypomagnesemia, uremia, hyperthyroidism, drug intoxication/poisoning/overdose
    • Medication associated with seizures: opioids, anticancer drugs, carbapenems, 4th generation cephalosporins, fluoroquinolones, isoniazid, penicillins, hypoglycemic agents, immunosuppressants, psychiatric medications, stimulants, sympathomimetics and decongestants
  • Vascular malformations
  • Familial/genetic, infantile, and pediatric seizure syndromes (e.g., Lennox-Gastaut, benign familial, myoclonic epilepsy of infancy)
  • Other etiologies (by age of onset)
    • Neonatal period
      • Benign neonatal seizures, benign familial neonatal epilepsy, EME, Ohtahara syndrome
    • Infancy (<2 years)
      • Febrile Seizures
      • Hypoxic-ischemic encephalopathy/other injury to cerebral cortex
      • Metabolic: hypoglycemia, hypocalcemia, hypomagnesemia, vitamin B6 deficiency, phenylketonuria
    • Childhood (2 to 10 years): absence or febrile (usually <6 years) seizure
    • Adolescent (10 to 18 years): AV malformation
    • Late adulthood (>60 years)
      • Degenerative disease, including dementia
      • Most common causes for symptomatic seizures in elderly patients are acute stroke, metabolic disturbances (hypoglycemia, uremia, hepatic failure, electrolyte abnormality), and drugs. Initial diagnostic testing should be focused on these common etiologies.

Genetics
Family history increases risk 3-fold.

Risk Factors

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

General Prevention

Take measures to prevent head injuries. Avoid sleep deprivation. Avoid excessive alcohol intake.

Commonly Associated Conditions

Genetic syndromes (Angelman, tuberous sclerosis, Sturge-Weber), infections, tumors, drug abuse, alcohol and drug withdrawal, trauma, metabolic disorders

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Basics

Description

  • Seizure: sudden and transient symptoms (altered level of consciousness, motor manifestations) due to abnormal neuronal electrical activity
  • Epilepsy: enduring preposition to generate epileptic seizures; defined as 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: epileptic seizure that lasts >5 minutes or multiple seizures without returning to normal between them. Classification: generalized, simple and complex partial, absence, nonconvulsive; based on three key features:
    • 1) Seizure origin: focal (previously partial), focal to bilateral, generalized
    • 2) Awareness: aware, focal impaired or generalized awareness
    • 3) Clinical features: motor, nonmotor (absence, behavior, cognitive, autonomic)
  • System(s) affected: nervous
  • Synonym(s): convulsion; attacks; spells

Pediatric Considerations
Sedation of the infant should be monitored.

Pregnancy Considerations

  • Preconception: Certain antiepileptic drug (AED) (P450 inducers) may cause hormonal contraceptive failure.
  • Pregnancy: Avoid valproate as possible, due to increased teratogenicity and poor developmental outcomes. During pregnancy, monitor AED levels every trimester for dose adjustment, continue folic acid supplementation, and screen for congenital abnormalities.
  • Levetiracetam, topiramate, lamotrigine are alternatives for women of childbearing potential (1).

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
326,000 children (≤14 years of age) and 600,000 adults (>65 years of age) have a seizure disorder.

Etiology and Pathophysiology

  • Synchronous and excessive firing of neurons, resulting in an imbalance of regulatory mechanisms in favor of excitatory activity. Seizures may be triggered by metabolic/medical conditions, but such seizures do not necessarily define the presence of epilepsy.
  • Acute symptomatic seizures: acute insult to the brain, medical illness, metabolic disturbance, substance/medication ingestion or withdrawal
    • Stroke, subdural hematoma, subarachnoid bleed, traumatic brain injury, hypoxic-ischemic injury
    • Acute infection: brain abscess, meningitis/encephalitis
    • Metabolic and endocrine disorders: hypo-/hyperglycemia, hyponatremia, hypocalcemia, hypomagnesemia, uremia, hyperthyroidism, drug intoxication/poisoning/overdose
    • Medication associated with seizures: opioids, anticancer drugs, carbapenems, 4th generation cephalosporins, fluoroquinolones, isoniazid, penicillins, hypoglycemic agents, immunosuppressants, psychiatric medications, stimulants, sympathomimetics and decongestants
  • Vascular malformations
  • Familial/genetic, infantile, and pediatric seizure syndromes (e.g., Lennox-Gastaut, benign familial, myoclonic epilepsy of infancy)
  • Other etiologies (by age of onset)
    • Neonatal period
      • Benign neonatal seizures, benign familial neonatal epilepsy, EME, Ohtahara syndrome
    • Infancy (<2 years)
      • Febrile Seizures
      • Hypoxic-ischemic encephalopathy/other injury to cerebral cortex
      • Metabolic: hypoglycemia, hypocalcemia, hypomagnesemia, vitamin B6 deficiency, phenylketonuria
    • Childhood (2 to 10 years): absence or febrile (usually <6 years) seizure
    • Adolescent (10 to 18 years): AV malformation
    • Late adulthood (>60 years)
      • Degenerative disease, including dementia
      • Most common causes for symptomatic seizures in elderly patients are acute stroke, metabolic disturbances (hypoglycemia, uremia, hepatic failure, electrolyte abnormality), and drugs. Initial diagnostic testing should be focused on these common etiologies.

Genetics
Family history increases risk 3-fold.

Risk Factors

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

General Prevention

Take measures to prevent head injuries. Avoid sleep deprivation. Avoid excessive alcohol intake.

Commonly Associated Conditions

Genetic syndromes (Angelman, tuberous sclerosis, Sturge-Weber), infections, tumors, drug abuse, alcohol and drug withdrawal, trauma, metabolic disorders

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