Exam 1: Seizures Flashcards
Seizures
abnormal or uncontrolled neuronal discharges in the brain
Disturbances of electrical activity in the brain that may effect
consciousness
motor activity
sensation
Paroxysmal episodes
- sudden, involuntary muscle contractions
- alterations in consciousness, behavior, sensation and autonomic functioning
Labeled epilepsy
if recurring
caused by chronic underlying condition
Episodes may be
Partial (simple or complex)
Generalized (absence, myoclonic, tonic, clonic or tonic-clonic)
Unclassified
Seizures: Identified Causes
- Pathological processes in brain: trauma, acute cerebral edema, infection, degeneration, neuronal injury, vascular anomalies or lesions
- Endogenous and exogenous toxic substances: uremia, lead ingestion, alcohol intoxication
- Metabolic disturbances
- Febrile states
- Developmental abnormalities
- Birth defects
Seizures: Pathophysiology
Internal and external stimulus causes abnormal hypersynchronous discharges in a focal area in the cerebrum.
Neuropeptides and neurotransmitters released and blood flow is increased.
Extracellular concentrations of potassium ↑; concentrations of calcium ↓.
Simple Partial Seizure: Clinical Manifestations
Motor: recurrent involuntary muscle contractions of one body part (face, hand, arm, legs) that may spread to other, same side body parts
Sensory: auditory or visual hallucinations
Psychic: sensation of déjà vu, complex hallucinations or illusions, unwarranted anger or fear, sweating
Complex Partial (psychomotor): Clinical Manifestations
Onset: may have aura before onset
Motor: automatisms (patting body parts, smacking lips, aimless walking, picking at clothes)
Sensory: 1-2 minutes of loss of contact with surroundings, hallucinations
Generalized Seizure: Clinical Manifestations
Absence (petit mal): transient loss of consciousness, flickering of eyelids, or intermittent jerking of hands
Myoclonic: rapid, jerky movements in extremities or over entire body, which may cause a fall
Tonic: intense muscle contraction with sudden abnormal dystonic posture, deviation of eyes, and head to one side
Clonic: Alternating contraction and relaxation of muscles to extremities for several minutes with loss of consciousness
Tonic-clonic (grand mal): aura,, loss of consciousness, cyanosis, fall; tonic then clonic contractions→ limpness, sleep, headache, confusion, loss of bladder/bowel control
Seizures: Complications
Injury from fall or jerking
Airway occlusion
Aspiration
Status epilepticus → MEDICAL EMERGENCY!
Status epilepticus
motor sensory or psychic seizures follow one another with no intervening periods of consciousness
Failure to get immediate treatment for status epilepticus leads to
Hypoxia Hyperthermia Hypoglycemia Acidosis Death
Convulsion
- Involuntary, violent spasms of large skeletal muscles of face, neck, arms and legs.
- Not synonymous with seizure.
How do antiseizure drugs affect oral contraceptives?
decreases effectiveness of oral contraceptives
Most antiseizure drugs are
pregnancy category D.
Eclampsia
severe hypertensive disorder of pregnancy, characterized by seizures, coma, and perinatal mortality
Antiseizure Pharmacotherapy Goals
suppress neuronal activity enough to prevent abnormal or repetitive firing
Antiseizure drugs act through 3 mechanisms
Stimulating an influx of chloride ions
Delaying an influx of sodium
Delaying an influx of calcium
Antiseizure Pharmacotherapy is directed at
- controlling movement of electrolytes across neuronal membranes or affecting neurotransmitter balance.
- some drugs act by more than one mechanism.
Drugs that potentiate GABA action include
Benzodiazepines: clonazepam (Klonopin), diazepam (Valium), lorazepam (Ativan)
Barbiturates: phenobarbital (Luminal)
Newer GABA-related drugs: gabapentin (Neurontin), topiramate (Topamax)
Drugs that suppress sodium influx include
Hydantoins: enytoin (Dilantin)
Phenytoin-like drugs: valproic acid (Depakene, Depakote)
Drugs that suppress calcium influx include
Succinimides: ethosuximide (Zarontin)
Drugs that potentiate GABA action act by
changing the action of gamma-aminobutyric acid, the primary inhibitory neurotransmitter in the brain.