Neurological Disorders: Epilepsy

Definition

Epilepsy is a common neurological disorder and is characterized by recurrent clinical manifestations of generally brief duration which are called as seizures or fits. A Neurologist is frequently involved in the care of these patients.

Clarification on the terminologies

Please note that the term epilepsy, seizure and fit may or may not be synonymous depending upon the context.

For a proper definition of epilepsies, in addition to the above statement (1st paragraph), it is also required that the seizures are the result of a chronic underlying brain pathology (example scar tissue, genetic conditions etc) rather than a temporary and/or avoidable condition like hypoglycemia (low blood glucose), hyponatremia (low blood sodium) etc.

The term fit or seizure is also used for the particular clinical episode a patient experiences. For example we may say he/she just had a seizure (or fit) but we do not usually say he/she just had an epilepsy. However in certain circumstance all these 3 terms may be used somewhat synonymously, for example, we may say he/she has epilepsy disorder OR seizure disorder OR fits disorder for the same condition.

But do not really worry about these terminologies; when you discuss your episode with neurologists or other physicians we almost always understand what you meant.

What causes Seizures?

Seizures are the result of irritation to the neurons (brain cells) that are generally located in the outer layers called as cerebral cortex. These neurons produce a burst of pathological electrical activity that manifests as seizures.

Myriad things can cause irritation or injuries to the neurons including;

• Genetically mediated
• Structural abnormalities of brain like tumors, scars, stroke etc
• Electrolyte abnormalities like low glucose, sodium in the blood
• Infections e.g. encephalitis
• Idiopathic (cause unknown)

How does patient present?

Based on what we see from outside the seizures are of several types; and they present with one of the below or a mixed pattern;

• Major motor manifestations
• Minor or no motor manifestations
• Behavioral changes

Patients with the first category present with various prominent motor activities mentioned below in isolation or in various combination;

• Tonic activities (stiffening) of limbs and/or body
• Clonic (convulsive or shaking) movements of limbs and/or body
• Tonic - clonic activities
• Head and/or eye turning to one side
• Bladder or bowel incontinence
• Tongue bite etc.

With the second category you may see these below manifestations, either alone or in combination;

• Episodes of blank stare
• Recurrent eye blinking
• Automatism (semi-purposeful gestures & movements e.g. lip smacking
) etc

The third category may present like this;

• Confusion/disorientation/behavioral changes

However not all seizures are expressed from outside, some of them may be sensory phenomenon or just experienced by the patients (subjective seizures), and we see nothing outwardly. Patient may experience recurrent abnormal sensations of hot or cold feelings, touch, pins & needles, pain etc.

Special senses including taste, visual, hearing, smell may be experienced too. Rarely seizures may present as brief duration headaches.

You may see a typical seizure passes through three distinct phases including;

1) Aura
2) The actual seizure presentation (see the above clinical manifestations)
3) Post-ictal state

Aura is considered as a simple partial seizure. It is the earliest manifestations of a seizure and not necessarily occurs with all seizures. They could be any kind including experiencing of abnormal taste, smell, or sensory/motor manifestations etc.

Post-ictal state is the temporary manifestation after the actual seizure presentation is over. The presentation varies and generally includes;

• Grogginess or sleepiness
• Confusion/disorientation
• Violent behavioral changes
• Frank psychotic manifestations like delusions, hallucinations etc
• Temporary limb paralysis example - Todd’s paralysis etc

Common types of Seizures

Grand mal seizures:

Also called as generalized tonic-clonic (GTC) seizures, the term tonic means stiffening of the body, and clonic means convulsive movements. If the seizure is primary generalized then it commences abruptly without any aura or focal features and patient loses consciousness. With secondary generalized type, seizure starts with focal features e.g. Head and eyes may twist to one side, an aura and post ictal phase may be seen. Tongue bites and losing bowel, bladder control are common.

Absence seizures (Petit-mal Epilepsy):

There are no major motor manifestations with this seizure. This type of epilepsy is more frequent in children. They are usually brief lasting for several seconds and recurrent in nature. During the attack they present with a blank stare, and do not respond. Some eye blinking, lip smacking may accompany. No auras or post-ictal manifestations are seen. A patient may experience several episodes per day. Sometimes kids with these seizures are labeled as absent minded or ADD (attention deficit disorder).

SPS (Simple partial seizures):

The term simple or complex in this context is used with regard to the mental status of the patient. With simple partial seizures patient is alert and not confused. If patient is not alert and is found confused then complex partial type. Patients usually present with seizure manifestation in a focal or localized area like arm, leg or face etc. A SPS can progress to develop into a CPS or secondary GTC.

CPS (Complex partial seizures):

These patients initially may experience some aura and then the actual seizure will manifest as a change in mental status in the form of confusion or disorientation. Minor motor phenomena like semi-purposeful body or limb movements (called as automatism) are generally seen e.g. hand automatism, repeated lip smacking etc. The seizure may last for few minutes then post-ictal manifestations are seen. A CPS can progress into a GTC.

Myoclonic seizures:

During these episodes patient experience sudden & brief duration jerking movements of limbs or body as if they were jolted by electric shocks. There are myriad conditions associated with myoclonic type seizures and JME (juvenile myoclonic epilepsy) is one such example.

Diagnosis

Once clinical suspicion or diagnosis of a seizure is made then depending upon the individual case the following neurology tests may be necessary;

• CT and/or MRI of brain
• EEG (routine, ambulatory, video eeg etc)
• Some times blood tests
• Some times CSF (cerebrospinal fluid) analysis
• Rarely genetic tests, biopsy
• Serum prolactin level if pseudo seizure is suspected

Treatment

Not all patients with seizure or epilepsy may require seizure medication and the decision is done on case to case basis.

Some of the commonly used anti-epileptic drugs (AED) include;

• Phenytoin
• Sodium Valproate
• Carbamazepine
• Oxcarbazepine
• Topiramate
• Levetiracetam
• Gabapentin
• Lamotrigine
• Pregabalin
• Phenobarbitone
• Primidone etc.

If medications are not helping much then in some cases ketogenic diet may be tried. If none of the non surgical options help then surgery has to be considered. VNS (vagal nerve stimulator) implantation and epilepsy brain surgery are the two commonly employed surgeries for medically refractory seizure disorder.

Epilepsy to Neurology Articles

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