Epilepsy - Understanding Seizures, its types and management

Epilepsy is a neurological condition in which the brain activity becomes abnormal causing episodes of unusual sensations, muscle activity, and awareness called a seizure.  At least 2 seizures without a known trigger occurring at least 24 hours apart are required for calling it epilepsy.

The manifestation of a seizure ranges from staring blankly or rolling of eyes, twitching, stiffening up or jerky movements, confusion, and anxiety, to loss of awareness or consciousness. Convulsions refer to rapid and rhythmic shaking and involuntary muscle contractions.

Epilepsy often may not have a definite identifiable cause. Some of the known causes include head trauma, stroke, vascular abnormalities in the brain, infections (meningitis, encephalitis, HIV), brain tumors, and brain damage before/around birth. Genetic predisposition, family history, and some conditions like autism or dementia are associated with epilepsy.

TYPES OF SEIZURES

Seizures are classified as focal (abnormal activity in just one area of the brain) or generalized (involving the whole brain).

Focal seizures

Also called partial seizures, these are of 2 types.

• Simple Partial or Focal seizures without loss of consciousness: These manifest as altered sensory perceptions (tingling, flashes, and abnormal smell/taste, sound or appearance), sometimes a sense of de ja vu, and twitching/jerking of one body part (like arm or leg).
• Complex Partial or Focal seizures with impaired awareness: There is an actual change in awareness (staring, not responding, feeling dream-like) or loss of consciousness, with abnormal and repetitive movements (walking in circles, chewing, smacking, swallowing, hand rubbing movements, etc.)

Generalized Seizures

These are of the following types.

• Absence seizures (petit mal): These manifest as staring into space, sometimes with mild movements like blinking or lip smacking, and may cause loss of awareness, all for a few seconds. These are more common in children and can occur on any single day several times.
• Tonic seizures: These cause muscles (arms, back, legs) to stiffen, and can cause one to lose balance or fall down, and lose awareness in some cases.
• Atonic seizures: These manifest as loss of muscle tone and control, causing the person to suddenly collapse or drop to the ground.
• Clonic seizures: These are rhythmically repetitive, jerking muscle movements, generally of the face, neck and arms.
• Myoclonic seizures: These appear as sudden short muscle twitches or jerks of the trunk, arms and legs.
• Tonic-clonic seizures (grand mal): These are pronounced and abrupt causing loss of consciousness, muscle stiffening, shivering/twitching, convulsions, and sometimes tongue bites or even urination.

Febrile Seizures

High fevers in childhood can sometimes be associated with seizures. But this is not, and generally does not develop into epilepsy unless there is a definite family history or other predispositions.

Seizures and Pregnancy

Seizures during pregnancy pose dangers to both mother and baby. Pregnant women with epilepsy are often on anti-epileptic medications that can increase the risk of birth defects, so regular monitoring is necessary. Eclampsia is a condition where there are seizures due to a severe complication of high blood pressure during pregnancy (preeclampsia). It puts the life of both mother and baby at very high risk and needs to be immediately controlled and treated.

Status epilepticus

It refers to continuous seizures or recurrent seizures without gaining consciousness in between for more than 5 minutes. This significantly increases the risk of permanent brain damage and danger to life.

DIAGNOSIS

Symptoms of focal seizures may sometimes be confused with other neurological disorders, such as migraine, sleep disorders like narcolepsy or psychological disorders.

A neurological examination is conducted, which includes neuropsychological tests to assess thinking, memory and speech skills, and an EEG (electroencephalogram) to assess brain activity. EEG may be video-EEG, ambulatory EEG (recording over 24 hours while one continues with normal activities) and high-density EEG (closer spacing of electrodes).

Imaging of the brain with different types of CT/MRI and PET scans may also be performed. Some newer combination diagnostic techniques include statistical parametric mapping (SPM) that compares areas of the brain that have increased blood flow during seizures to indicate seizure origin site, electrical source imaging (ESI) that projects EEG data onto a brain MRI to identify seizure sites, and magnetoencephalography (MEG) that measures the magnetic fields produced by brain activity to identify potential seizure origin sites.

Blood investigations also are ordered for screening associated conditions.

MANAGEMENT

Antiepileptic Drugs

These drugs help to control seizures by blocking ionic channels in the brain (sodium or calcium channels), or modifying neurotransmitters (potentiating inhibitory neurotransmitter GABA or reducing the excitatory neurotransmitter glutamate). Some drugs can act by both of these, as well as additional mechanisms.

The older group of antiepileptic drugs includes barbiturates (phenobarbital), phenytoin, carbamazepine, ethosuximide, and valproate. The newer antiepileptics drugs are topiramate, lamotrigine, oxcarbazepine, zonisamide, tiagabine, vigabatrine, and levetiracetam. These drugs can be used to prevent all kinds of seizures, while the drug ethosuximide is used for absence seizures.

Gabapentinoid drugs like pregabalin and gabapentin are used mainly for partial seizures. Benzodiazepine drugs like diazepam, lorazepam and clonazepam are used to control active seizures and status epilepticus.

Antiepileptic drugs are very effective and have helped most people with epilepsy lead a fulfilled life. However, these medicines can have side effects like nausea, abdominal pain, indigestion, dizziness, fatigue, sleepiness, irritability, anxiety or mood changes, weight gain, and blurry vision. These medicines should be taken strictly under medical guidance and monitoring. They are also known to affect the fetus during pregnancy, so all information of one’s epilepsy condition and treatment should be shared with the treating obstetrician when pregnant.

Procedures and Surgery

It is considered in those patients who show well-defined small seizure origin sites which do not interfere with vital functions like vision, speech, hearing, or motor function. Procedures include minimally invasive like MRI-guided stereotactic laser ablation or ultrasound, and open surgery if the risk is not high. Anti-epileptic drugs, possibly at a lower dose may still be needed post-surgery. Rarely cognitive abilities may be impacted after surgery that may need appropriate rehabilitation.

Other non-invasive options include vagus or trigeminal nerve stimulation, deep brain stimulation, neurostimulation with implantable pacemaker-like devices, transcranial magnetic stimulation, and continuous subthreshold stimulation of the seizure onset zone.

PRECAUTIONS

The available medicines to prevent and manage seizures, help most people with epilepsy have a very good quality of life. A few precautions are important to be kept in mind:

• Be regular with your medicines. Also always carry at least one dose for managing an active seizure with you when you are outside your home. It also helps to carry an info card about your condition and medicine to be taken in your bag/wallet.
• Family and close friends should know how to recognize an impending seizure, and about the risk of falling and sometimes serious injuries during a seizure.
• Extreme care while driving is needed, especially if the seizure can cause a lack of awareness or consciousness. It is important to check one’s country’s or state’s policy on driving policy about seizure-free intervals and control for driving eligibility.
• If a seizure occurs when in water (swimming or tub bathing), the risk of drowning is greatly increased.
• Overall meticulous care should be taken with all associated health problems. People with epilepsy especially those with generalized tonic-clonic type and not well controlled on medications have a small risk of sudden unexpected death in epilepsy (SUDEP), possibly due to cardio-respiratory problems.
• Positive emotional support and reinforcement are very helpful to reduce the occurrence of anxiety, depression and other psychological problems in people who get seizures.

Also read:

Stroke and Cerebrovascular Disease – 5 Important Points

Chronic Headache – Causes, When and How to act

Understanding and Recognizing Sleep Disorders