Epilepsy is a syndrome characterized by recurrent paroxysmal episodes of abnormal or excessive cortical electrical charges

Epilepsy may affect 0.5% - 2.0% of the US population and is the second most common neurological disorder.

Etiology

Can be caused in some individuals by a cerebral dysrhythmia (threshold for seizure activity is lower than normal).

Can occur as a result of structural injury, metabolic & nutritional disorders (electrolyte/ water imbalance and hypoxia) or as a idiopathic disorder (no known cause).

Triggered by physical (specific sensory stimuli) and psycho-social factors.

Pathogenesis

Epilepsy is due to alteration in the membrane potential that makes certain neurons abnormally hyperactive to changes in their environment.

Neurons in an epileptogenic focus (area where seizure emanates) can recruit neighboring and synaptically related neurons to emit excessively large numbers of electrical charges.

Classification

Partial Seizures - seizures involving only part of the brain.

In simple partial seizures the individual does not lose consciousness; may experience tingling or numbness.

Complex partial seizures begin as simple partial seizures that progress to the impairment of consciousness.

General Seizures - involve the entire brain.

Absence or Petit Mal seizures - usually occur in children, very brief (2-10s) ; characterized by short staring spells.

Atypical Absence seizures - characterized by muscle jerks.

Myoclonic seizures - extremely brief; characterized by a single jerk of one or more muscle groups.

Atonic seizures - sometimes associated with muscle jerking.

Clonic seizures - involves jerking of muscle groups.

Tonic seizures - results in stiffening of muscle groups.

Individuals may experience an aura (an odd sensory experience) seconds before consciousness is lost.

Grand Mal Seizure - person experiences loss of consciousness and falls to the ground.

Tonic Phase (10-15s) - initial motor signs include opening of mouth and eyes, extensions of legs, adduction of arms and the jaws snap shut; respiratory muscles go into tonic spasm making breathing impossible; skin and mucous membranes become cyanotic; bowel and bladder may empty.

Clonic Phase (1-2 min.) - trembling rapidly leads to violent rhythmic contractions; eyes roll, face grimaces, pulse accelerates, salivation increases and the individual sweats profusely.

Terminal Phase (~5 min.) - marked by a complete absence of movement in which individual is limb and in a deep coma, after which time the confused and disoriented individual will begin to gain consciousness.

Status epilepticus - potential life threatening situation in which there is a continuing series of seizures without an intercritical period of recovery. Can cause ischemic brain damage if left untreated for more than 30 - 40 minutes.

Diagnosis and Treatment

Initial diagnosis using electroencephalogram (EEG), computed tomography (CT), and magnetic resonance imaging (MRI) as well as lab test to investigate metabolic abnormalities.

During a seizure attention should be paid to maintaining an airway and protecting the individual from harm. If recording the seizure in a lab, attention should be paid to locating the epileptogenic focus.

Long term management may include may include surgical excision of diseased tissue, anti-convulsant medication and patient education.

Lifestyle changes are often required for affected individuals.