Seizures

• Predisposing factors that may cause epilepsy more often

  • Sleep deprivation
  • Hyperventilation
  • Fever from underlying illness
  • Hormonal changes occurring during menses
  • Drug or alcohol ingestion
• All of these may lower the seizure threshold and provoke seizures in people who are predisposed
• Disorders associated with seizures

  • Acute metabolic
  • Infectious
  • Medication-related
  • Alcohol or drug withdrawal
  • Viral meningitis
  • Hypoglycemia from an overdose of insulin
• International League Against Epilepsy (ILAE) classification system

  Categorizes seizures based on where seizures begin in the brain, level of awareness during a seizure, and other features of a seizure
• ILAE seizure categories


  • Focal onset
  • Generalized onset
  • Unknown onset
• Focal onset seizures


  • Begin in a localized area of the brain, although there may be generalization to involve both hemispheres
  • Focal onset aware seizures (simple partial seizures) typically result in no alteration of consciousness
  • Focal onset impaired awareness seizures (complex partial seizures) are associated with impaired consciousness and with some form of automatic behavior (automatisms)
• Generalized seizures


  • Involve both hemispheres of the brain from the onset, and they result in early loss of consciousness
  • Generalized non-motor seizures may involve only loss of consciousness (similar to absence seizures)
  • Generalized motor seizures include tonic–clonic, clonic, or myoclonic seizures
• Absence seizures (petit mal)


  Sudden onset, brief (often lasting <10 seconds), interrupt ongoing activities, patient exhibits a blank stare and is usually unresponsive, may have some mild clonic or tonic jerking, abrupt onset and discontinuation, no postictal confusion, EEG shows a very rhythmic, 3 cycles/s spike-wave discharge
• Tonic–clonic seizures (grand mal)


  Abrupt loss of consciousness, sudden, sharp, bilaterally symmetric contraction of muscles, may cry, fall, or do both, head may be extended and appear cyanotic, may be associated tongue biting and incontinence
• Clonic seizures


  Rapidly repetitive bilateral jerking of the extremities and facial muscles with loss of consciousness, postictal phase is usually short
• Atonic seizures (drop attacks or astatic seizures)


  Sudden loss of muscle tone, may be brief and not associated with loss of consciousness, can occur in a repetitive, rhythmic, and successive manner
• Myoclonic seizures


  Sudden, brief, shock-like muscular contractions, may be generalized or confined to the face and trunk muscles, to one or more of the extremities, or to individual muscle groups
• Tonic seizures


  Brief, generalized tonic contractions with associated head extension, possible stiffening of the back, and stiffening of all four extremities, can be associated with autonomic symptoms, a rapid heart rate, and cessation of breathing followed by cyanosis
• Unknown onset seizures


  Occur when the beginning of a seizure is not known or witnessed by anyone, may be diagnosed as focal or generalized seizures later on when more information about the seizure is available
• Accurate diagnosis of seizure is imperative to initiate correct drug therapy
• Thorough history and physical may elicit a diagnosis without further testing
• Symptoms during seizure


  • LOC?
  • Precipitating events?
  • Motor symptoms, etc.
• EEG is the most useful test to assist in the diagnosis
• MRI/CT scan is also recommended for first unprovoked seizure
• MRI is preferred in children
• PET scan can be helpful in partial seizures but may not be covered by insurance
• Neurosurgery has a high success rate and should be considered for patients that have failed multiple medical therapies or have intolerable adverse drug effects
• Drug treatment of epilepsy

  Designed to reduce the number of seizures while limiting adverse effects of the medication, a realistic goal is to completely control seizures, ideally achieved with monotherapy, another goal is improving the patient's quality of life by allowing a return to normal activities of daily living without restriction
• Gabapentin has no significant drug reactions
• Gabapentin


  • Very well tolerated
  • Most common side effects are somnolence, dizziness, ataxia, fatigue, nystagmus and peripheral edema
• Pregabalin (Lyrica)


  An analog of GABA, used for neuropathic pain associated with diabetic neuropathy, postherpetic neuralgia, adjunctive therapy of partial seizures and fibromyalgia
• Lamotrigine


  Therapeutic uses include broad spectrum of anti-seizure activity and bipolar disorder
• Lamotrigine


  • Adverse effects are dizziness, diplopia, blurred vision, nausea, vomiting, headache, severe skin reactions, aseptic meningitis and risk for suicide
• The mechanism of action of levetiracetam is unknown
• Lacosamide


  Add on therapy for partial onset seizures in patients 17 and older
• Zonisamide


  Adjunct therapy of focal onset in adults
• Ezogabine


  First in its class potassium channel opener, used for adjunctive treatment of partial onset seizures
• Lorazepam (Ativan)


  Used intravenously to treat SE and has an unlabeled use for focal onset impaired awareness seizures
• Management of generalized convulsive status epilepticus

  1. Maintaining ventilation

  2. Correcting hypoglycemia

  3. Terminating the seizures
• Drugs of choice for generalized convulsive status epilepticus

  Benzodiazepines, with lorazepam recommended first line and diazepam if lorazepam is not readily available
• First-line selection of appropriate therapy

  1. Select the appropriate drug and dose for the type and severity of the seizure being treated

  2. Consider the patient's characteristics (e.g. hepatic or renal insufficiency, liver disease, hypoalbuminemia, burns, pregnancy, malnutrition, concomitant medications, age, compliance, adverse events)

  3. Determine the patient's socioeconomic status
• Before switching to a second-line agent, the practitioner must optimize treatment with the selected first-line drug (unless the patient experiences intolerable adverse effects) and exhaust all possible first-line drug therapy choices</b>
• If all medications fail and the patient experiences intractable seizures, surgery may be a third-line treatment option</b>
• A patient's response to a given AED is dependent on both environmental and genetic factors</b>
• Pharmacogenetic variations exist that may impact therapeutic response, enzyme activity, transporter activity, or even drug-related toxicity</b>