Seizures are caused by an electrical discharge from neurons in the cerebral cortex. Signs and symptoms of seizures vary according to the site of neuronal discharge in the brain. Manifestations generally include sensory, motor, autonomic, are psychic phenomenon. Epilepsy is a condition which n individual is predisposed to two or more recurrent seizures because of a CNS disorder.
Types of seizures:
I. Partial (focal, local) seizures
- Simple partial seizure: no loss of consciousness, unilateral hemispheric involvement, abnormal motor, sensory, autonomic, or psychic behavior. Can affect any part of the body. Typical age of onset is 3-15 years. A partial seizure is classified primarily on the basis of whether or not consciousness is impaired during the attack.
- Complex partial seizure: consciousness is impaired, aberrations of behavior may occur (automatisms). Automatisms include automatic motor behaviors such as chewing, smacking lips, and walking about. Usually begins as a simple partial seizure progressing to impairment of consciousness. The patient may remember initial autonomic or psychic symptoms (which are then termed as aura), but is amnesic for the rest of the seizure. The aura is usually characterized by unusual sense of smell, taste, visual or auditory hallucinations, and/or stomach upset. The person often appears confused. Complex partial seizures can occur at any age.II.
II. Generalized seizures: involve both hemispheres of the brain, Motor manifestations are bilateral,
consciousness may be impaired.
- Absence (Petit mal): the hallmark of an absent seizure is a sudden onset of a blank stare. This blank stare may last 3 to 50 seconds accompanied by impaired level of consciousness. All activities will be interrupted during an absence seizure. There is no abnormal motor movement. Usual age of onset is 3-15 years.
- Tonic-clonic (Grand mal): the most frequent encountered generalized seizure. There is a sudden tonic contraction of muscles, stridor, and/or a cry. The patient falls to the ground in the tonic state and lies rigid. The tonic contraction inhibits respirations and cyanosis may occur. The tongue maybe bitten and the patient may be incontinent of bladder and bowel. This tonic stage progresses to clonic convulsive movements (rigid extension of arms and legs followed by jerking movements with loss of consciousness). Onset may occur at an age. A new onset in adults may indicate brain tumor, post-head injury, and alcohol withdrawal.
- Myoclonic: sudden, brief shock-like contractions. These abnormal motor movements may last seconds to minutes and may be generalized or confined to the face or trunk. These seizures are difficult to control and patients with the seizures also have tonic-clonic seizures. Usual age of onset is 2-7 years.
III. Unclassified seizures: includes all seizures that cannot be classified because of inadequate or incomplete data. This includes some neonatal seizures, such as rhythmic eye movements, chewing, and swimming movements.
Pseudoseizures: movements that may mimic seizures but are due to a conversion reaction (a psychological disorder)
Status Epilepticus: a continual seizure. If untreated or not stopped can lead to death due to respiratory failure. A medical emergency.
Causes of seizures: a great variety of disorders and causes can initiate seizures.
- Drug overdose
- Drug withdrawal
- Head trauma
- Degenerative brain disease
- Developmental brain defects
- Systemic problems (fever, infection, sleep deprivation)
- Metabolic imbalances (hypocalcemia, hypoglycemia, hyponatremia, and hypoxia)
- Genetic defects (mutations in ion channels)
- Get a good history: setting in which seizure occurred, stimulus provoked, event occurring days before seizure, was there an aura, family history, and postictal behaviors
- Determine if there are signs of permanent nervous system dysfunction or evidence of a focal brain lesion
- Assess for signs of increased intracranial pressure, language difficulties, and drug toxicity (nystagmus, ataxia, diplopia, or tremor)
- An eye and visual examination will detect papilledema and visual field cuts (associated with focal brain lesions)
- Assess cranial nerves
- Moter exam should be symmetrical
- A cardiovascular exam will detect heart arrhythmia or murmurs which may suggest a syncopal episode rather than a seizure
- Carbamazepine (Tegretol), phenytoin (Dilantin)
- Valproic acid (Depekote/Depakene), lamotrigine (lamicital), gabapentin (Neurontin), benzodiazepines, barbiturates
- Adjunct: Tiagabine, (Gabitril), topiramate (Topamax) , levetiracetam (Keppra), zonisamide
Generalized seizures: Tonic-clonic (grand mal):
- Carbamazepine (Tegretol), phenytoin (Dilantin)
- Valproic acid (DDs), lamotrigine(lamicital), gabapentin, benzodiazepines, barbiturates
- Adjunct: Topiramate (Topamax), zonisamide
Absence (petit mal):
- Ethosuximide (Zarontin)
- Valproic acid (when absence seizures coexist with tonic-clonic seizures)
- Adjunct: Lamotrigine, benzodiazepines
Anticonvulsants & Pregnancy:
- Proper treatment can prevent seizures & complications for mom and baby
- Pregnant women metabolize, respond to AEDs differently than non-pregnant women, so close monitoring is very essential
- Risk of serious fetal malformations:
- 2% in general population (no epilepsy, no drugs)
- Only 3% overall effective treatment with one drug
- Risk of adverse fetal effects rises dramatically as AEDs are added