Seizure

Aka: Seizure, Convulsion, Epilepsy, Seizure Disorder

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II. Definitions

  1. Seizure
    1. Excessive synchronous, abnormal cortical Neuron electrical activity resulting in transient findings
  2. Epilepsy
    1. Two or more unprovoked, afebrile Seizures more than 24 hours apart OR
    2. One unprovoked first Seizure with a 60% risk of second Seizure in 10 years (based on risk factors)

III. Epidemiology

  1. Seizure lifetime risk: 10%
  2. Epilepsy diagnosis lifetime risk: 3.9%
  3. U.S. Prevalence: 1% (since Seizure Disorder does not persist in many, e.g. children)
  4. Gender: Males slightly more than females
  5. More common in low and middle income countries (account for 80% of worldwide cases)
    1. Worldwide, associated with socioeconomic deprivation and lack of access to healthcare
    2. More common in regions with higher rates of congenital conditions, intracranial infection, Head Injury
    3. Heaney (2002) BMJ 325(7371): 1013-6 [PubMed]
  6. Age: Bimodal Peak Onset
    1. Infants
    2. Older adults (ages 55 to 75 years)

IV. Causes

  1. See Seizure Causes

V. Types

  1. Secondary Seizures (provoked, Situation-Related Seizures) due to underlying lesion (40% of cases)
    1. See Seizure Causes (includes Drug Induced Seizure and Seizure Differential Diagnosis)
    2. More common in older patients (whereas unprovoked Seizures are more common in younger patients)
    3. Most common causes
      1. Cerebrovascular Accident
      2. CNS Infection
      3. Traumatic Brain Injury
      4. Congenital (e.g. Cerebral Palsy)
  2. Primary Generalized Seizures
    1. See Status Epilepticus
    2. Generalized Tonic Clonic Seizure (Grand Mal Seizure, generalized motor Seizure)
    3. Absence Seizure (Petit Mal Seizure, generalized, non-motor Seizure)
  3. Primary Focal Seizures (Partial Seizures, single hemisphere)
    1. Awareness
      1. Focal Seizure Without Impairment of Awareness (Simple Partial Seizure)
      2. Focal Seizure with impaired awareness (Complex Partial Seizure)
    2. Subtypes
      1. Motor Seizures (focal motor activity)
      2. Sensory Seizures
      3. Autonomic Seizures (e.g. sweating)
    3. Common Focal Seizure syndromes
      1. Rolandic Epilepsy
  4. Other types
    1. Epileptic spasms (e.g. Infantile Spasms)

VI. Signs

  1. Limb jerking movements
  2. Muscle stiffness or rigidity
  3. Head Turning
  4. Eye Rolling
  5. Drooling
  6. Altered Level of Consciousness
  7. Altered breathing pattern
  8. Tongue Biting
  9. Urinary Incontinence
  10. Vital Sign abnormalities

VII. Differential Diagnosis

  1. See Seizure Differential Diagnosis

VIII. Labs

  1. See First Seizure Evaluation
  2. See Status Epilepticus
  3. Bedside Glucose
  4. Drug level monitoring indications
    1. Establish therapeutic concentrations when adequate Seizure control reached
    2. Clinical toxicity suspected
    3. Noncompliance suspected
    4. Expected variability in Pharmacokinetics
      1. Extremes of age
      2. Change of drug formulation
      3. Pregnancy
    5. References
      1. Tomson (2007) Cochrane Database Syst Rev (1):CD002216 [PubMed]

IX. Imaging: Structural study

  1. See Seizure Indications for Neuroimaging

X. Evaluation

  1. See Seizure Evaluation (includes Single Seizure Evaluation)

XI. Management: General

  1. See Status Epilepticus
  2. Seizure Prophylaxis
    1. See Seizure Prophylaxis for indications
    2. See specific Seizure types for optimal management
      1. Generalized Seizure (includes Generalized Tonic Clonic Seizure, Myoclonic Seizure)
      2. Absence Seizure
      3. Focal Seizure (includes simple and Complex Partial Seizure)
  3. Other adjuncts
    1. Ketogenic Diet (high fat, low Carbohydrate, low Protein)
      1. Associated with gastrointestinal side effects (Vomiting, Abdominal Pain, altered stool consistency)
      2. Risk of high Uric Acid, renal stones, decreased Calcium, Magnesium, QT Prolongation, Cardiomyopathy
      3. Poor level of evidence for support
      4. Martin (2016) Cochrane Database Syst Rev (2): CD001903 [PubMed]
    2. Vagus Nerve Stimulation
      1. Indicated for over age 12 years with medically refractory Epilepsy who are not surgical candidates
      2. Battery-powered stimulator/Pacemaker with leads at Vagus Nerve
      3. Morris (2013) Neurology 81(16): 1453-59 [PubMed]
    3. Responsive neurostimulation
      1. Similar to Vagus Nerve stimulator, but leads are inserted into the actual Seizure focus
      2. In response to sensing abnormal electrical activity, neurostimulator delivers electrical stimulation
      3. Risk of implant site infection, Headache, dysesthesia
      4. Bergey (2015) Neurology 84(8): 810-7 [PubMed]

XII. Management: Special topics

  1. Epilepsy in Pregnancy
    1. See Epilepsy in Pregnancy
    2. Contraception is key
      1. Estrogen-based Contraception is less effective in those on antiepileptic drugs
    3. Plan pregnancy on non-Teratogenic agents
      1. Major birth defects occur in 4-7% of those born to mothers on Seizure Prophylaxis monotherapy
  2. Driving
    1. Most U.S. states require no driving for 3-12 months since last Seizure
    2. Exact duration of non-driving varies by state
      1. http://www.epilepsy.com/driving-laws
  3. Physical Activity
    1. Physical Activity is recommended in Epilepsy (may decrease Seizure frequency)
    2. Most sports are not contraindicated in well controlled patients (e.g. biking, Contact Sports, swimming)
    3. Avoid high risk sports (e.g. hang gliding, Scuba Diving, free climbing)
  4. Screen for comorbid neuropsychiatric disorders
    1. Cognitive Impairment and Mood Disorders are common in Seizure Disorder (which may affect compliance)

XIII. Management: Surgery for Medically refractory Epilepsy

  1. Seizures continue despite antiepileptic drug prophylaxis in 30% of patients
  2. Surgical resection of Seizure focus results in Seizure resolution in 76% of cases
  3. Predictors of Seizure-free after surgery
    1. Seizures without loss of consciousness
    2. Complete or extensive Seizure focus resection
    3. Prolonged Febrile Seizures
  4. Predictors of continued Seizures after surgery
    1. Non-structural Epilepsy
    2. Normal MRI
    3. Generalized Tonic-Clonic Seizures
    4. Infantile Spasms
    5. Tonic Seizures
    6. Invasive EEG monitoring to identify Seizure focus
  5. Complications
    1. Neurologic deficits (5%)
      1. Verbal memory deficits occur with Temporal Lobe resection (44% with left-sided resection)
    2. Medical complications (e.g. CSF Leak, Hydrocephalus, Aseptic Meningitis)
    3. Operative mortality (<0.5%)
  6. References
    1. Jobst (2015) JAMA 313(3): 285-93 [PubMed]

XIV. Complications

  1. Todd's Paralysis
  2. Sudden Unexplained Death in Epilepsy (SUDEP)
    1. Idiopathic Epilepsy related death (no other cause identified)
    2. More common in nocturnal Seizures
    3. Effective Seizure Prophylaxis lowers risk
    4. Typically in young adults (rare in children)
    5. Incidence: 9 per 1000 with Epilepsy (up to 1 in 150 for poorly controlled Seizures)
    6. Surges (2012) Curr Opin Neurol 25(2): 201-7 [PubMed]

XV. References

  1. Nocera, Valente, Amanullah (2018) Crit Dec Emerg Med 32(11): 3-9
  2. Wilfong (2017) Epilepsy in Children, UpToDate, accessed 7/17/2017
  3. Liu (2017) Am Fam Physician 96(2): 87-96 [PubMed]
  4. Rowland (2022) Am Fam Physician 105(5): 507-13 [PubMed]

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