Seizure

Seizure
1. Excessive synchronous, abnormal cortical Neuron electrical activity resulting in transient findings
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)

Seizure lifetime risk: 10%
Epilepsy diagnosis lifetime risk: 3.9%
U.S. Prevalence: 1% (since Seizure Disorder does not persist in many, e.g. children)
Gender: Males slightly more than females
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]
Age: Bimodal Peak Onset
1. Infants
2. Older adults (ages 55 to 75 years)

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)
Primary Generalized Seizures
1. Generalized Tonic Clonic Seizure (Grand Mal Seizure, generalized motor Seizure)
2. Absence Seizure (Petit Mal Seizure, generalized, non-motor Seizure)
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
Other types
1. Epileptic spasms (e.g. Infantile Spasms)

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
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
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)
Screen for comorbid neuropsychiatric disorders
1. Cognitive Impairment and Mood Disorders are common in Seizure Disorder (which may affect compliance)

Seizures continue despite antiepileptic drug prophylaxis in 30% of patients
Surgical resection of Seizure focus results in Seizure resolution in 76% of cases
Predictors of Seizure-free after surgery
1. Seizures without loss of consciousness
2. Complete or extensive Seizure focus resection
3. Prolonged Febrile Seizures
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
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%)
References
1. Jobst (2015) JAMA 313(3): 285-93 [PubMed]