Epilepsy

VENKATACHALAM

Epilepsy is simply defined as a disorder of the brain in which nerve cells do not signal properly. Seizures stem from an uncontrolled burst of electrical activity which results in clinical manifestations that may include loss of awareness or consciousness, behavioral changes, abnormal motor movements, and occasionally transient sensory changes.

There are two major subtypes of seizures: petit mal and grand mal. Petit mal seizures start in childhood and extend into adulthood. A petit mal seizure is a transient loss of awareness with eye fluttering and/or hand twitching that occurs for seconds. A grand mal seizure usually has a loss of consciousness followed by generalized convulsions of the limbs. Patients can also experience tongue biting or urinary incontinence. The patient’s head and gaze usually deviate to one side. The whole episode may last three to five minutes, and the patient will gradually wake up and regain consciousness. Patients may be confused for a short period of time before returning back to their baseline. Dacrystic seizures are seizures when a person makes a crying sound. There is another seizure called partial complex with secondary generalization. There is also another rare type of seizure, which usually starts in teenagers, called juvenile myoclonic seizure. A subset of seizures includes those classified as secondary or symptomatic. Some examples include post-traumatic brain injury (TBI); transient ischemic attack (TIA), a.k.a. stroke; or brain tumors. Notably, one to five percent of cortical strokes are complicated by a seizure disorder.

Some epileptic syndromes arise from a genetic abnormality. The International League Against Epilepsy (ILAE) classifies this subset as idiopathic generalized epilepsy (IGE). According to the ILAE, some examples of IGE include juvenile myoclonic epilepsy, juvenile absence epilepsy, and childhood absence epilepsy. Patients may require an MRI of the brain to look for structural disorders that include heterotopic brain and radial migration line disorders and tuberous sclerosis. Dravet syndrome, also known as severe myoclonic epilepsy of infancy, was found to have a genetic association with the voltage-gated sodium channel SCN1A found on chromosome zq24. It is an epileptic syndrome associated with encephalopathy. Lennox-Gestaut syndrome (LGS) is a severe form of epilepsy that typically starts in infancy or childhood. It is usually caused by a genetic abnormality or brain injury from infection or trauma. LGS is difficult to treat and is often associated with developmental delays. The ILAE task force has classified this disorder as epileptic encephalopathy. Medications such as Onfi (clobazam), Banzel (rufinamide), and inhaled cannabinoids may help. A brain MRI to identify cortical dysplasia may also be advised.

At this time, epilepsy does not have a cure but can be well controlled through treatment with antiepileptic drugs. The mechanism of action of antiepileptic and anticonvulsant drugs to prevent seizure is variable. One mechanism involves decreasing the excitation of cortical neurons or enhancing the inhibition of cortical neurons. Another mechanism involves altering the neuronal electrical activity by affecting ion channels in the cell membrane. In general, antiepileptic medications are always continued in adults for driver’s license maintenance, but an adult should not drive after a seizure for at least six months. Along the same lines, the rule of thumb is to never stop antiepileptic drugs in juvenile myoclonic seizures or symptomatic seizures. Prolonged or back-to-back seizures may require hospitalization and acute management with intravenous medications, such as Keppra (levetiracetam) and Depakote (sodium valproate), and/or nasal sprays, including Valtoco (diazepram) and Versed (midazolam). When multiple antiepileptic drugs fail to work, patients may need surgical intervention with a lobotomy procedure.

Some seizures result in a postictal period and can be associated with crying spells or laughing spells lasting up to a minute with grunting, mumbling, lip smacking, or fidgetiness. Some seizures present with automatism, which is characterized by hand wringing (clasping together of hands and squeezing), involuntary movements, lip smacking, or running in circles. Automatism occurs when the seizure discharge emanates from an area of the brain called the amygdala. Patients can also develop autonomic dysfunction, such as abnormal blood pressure, irregular heart rhythms, and slurring of speech, and patients may have a drop attack and syncope. Patients will need to follow a neurologist on a regular basis and may require periodic electrophysiologic testing, known as routine EEG, which is usually completed in 35 minutes but can also be a 24-hour continuous EEG. More extensive monitoring can also be done for three days duration in an epilepsy monitoring unit. At the time of a seizure, an EEG will be abnormal for the majority of the time.

Migraines may also be seen in epileptic patients. In that case, a drug will be prescribed that will help both epilepsy and the migraines. Examples include Depakene (valproic acid), Lamictal (lamotrigine), Topamax (topiramate) and Zonegran (zonisamide). In order to improve compliance, some drugs are available in an extended-release formulation. Compliance is a key factor in reducing seizure recurrence. Some patients may have recurrent seizures with prolonged unconsciousness. If a seizure lasts 30 minutes or longer, that is known as status epilepticus, which can be fatal and requires the patient to be hospitalized and potentially mechanically ventilated to maintain airway flow. Sudden death has been rarely reported in epileptic patients.

In conclusion, epilepsy is a very complex neurological disorder. We must remain informed and aware to potentially help someone who may be in need.