Epilepsies

Dr. Prem Pillay , Singapore Brain Spine Nerves Center, Singapore

Senior Consultant Neurosurgeon with super speciality training in Neurosurgical Oncology

(Fellow at MD Anderson Cancer Center and Hospital, U of Texas, USA)

Epilepsy is a disorder of the brain characterised by repeated seizures. A seizure is usually defined as a sudden alteration of behaviour due to a temporary change in the electrical functioning of the brain. Normally, the brain continuously generates tiny electrical impulses in an orderly pattern. These impulses travel along neurons, the network of nerve cells in the brain and throughout the whole body via chemical messengers called neurotransmitters.

In epilepsy, the brain’s electrical rhythms have a tendency to become imbalanced, resulting in recurrent seizures. In patients with seizures, the normal electrical pattern is disrupted by sudden and synchronised bursts of electrical energy that may briefly affect their consciousness, movements or sensations.

Epilepsy is usually diagnosed after a person has had at least two seizures that were not caused by some known medical condition, such as alcohol withdrawal or extremely low blood sugar.

If seizures arise from a specific area of the brain, then the initial symptoms of the seizure often reflect the functions of that area. The right half of the brain controls the left side of the body, and the left half controls the right side. For example, if a seizure starts from the right side of the brain in the area that controls movement in the thumb, then the seizure may begin with jerking of the left thumb or hand.

Types of Seizures

Seizures vary so much that epilepsy specialists frequently reclassify seizure types. Typically, seizures belong in one of two basic categories:

• Primary generalised seizures

  Begin with a widespread electrical discharge involving both sides of the brain at once.

  
  

• Partial seizures

  Begin with an electrical discharge in one limited area of the brain.

  
  

Epilepsy in which the seizures begin from both sides of the brain at the same time is called primary generalised epilepsy. Hereditary factors are important in primary generalised epilepsy, which is more likely to involve genetic factors than partial epilepsy — a condition in which the seizures arise from a limited area of the brain.

Some partial seizures are related to head injury, brain infection, stroke or tumour, but in most cases, the cause is unknown. One question that is used to further classify partial seizures is whether consciousness (the ability to respond and remember) is impaired or preserved.

Factors That May Increase Seizure Risk

• Stress

• Sleep deprivation or fatigue

• Insufficient food intake

• Alcohol use or drug abuse

• Failure to take prescribed anticonvulsant medical therapy

  
  

About half of the people who have one seizure without a clear cause will have another one, usually within six months. A person is twice as likely to have another seizure if there is a known brain injury or other type of brain abnormality. If the patient has two seizures, there is about an 80 percent chance of having more.

If the first seizure occurred at the time of an injury or infection in the brain, it is more likely the patient will develop epilepsy than if the seizure did not happen at the time of injury or infection.

Prevalence and Incidence

According to the Epilepsy Foundation, epilepsy affects three million people in the U.S. and 50 million worldwide. Seizures may be tied to a brain injury or genetics, but for 70 percent of patients, the cause is unknown.

• 10 percent of people will have seizures in their lifetime.

• More than 300,000 children under the age of 15 have epilepsy, with 90,000 of them having seizures that cannot be adequately treated.

• The onset rate increases with age, particularly in cases of stroke, brain tumours, or Alzheimer’s disease.

• Over 570,000 adults over 65 suffer from the disorder.

• More men than women have epilepsy.

Children and adolescents are more likely to have epilepsy of unknown or genetic origin.Brain injury or infection can cause epilepsy at any age.

The Epilepsy Foundation reports:

• 70 percent of children and adults with newly diagnosed epilepsy can enter remission after five years without a seizure while on medication.

• 75 percent of people who are seizure-free on medication can eventually be weaned off it.

• 20 percent of patients have intractable seizures — seizures that do not respond to treatment.

  
  

Epilepsy Risk Factors

• Premature birth or low birth weight

• Trauma during birth (such as lack of oxygen)

• Seizures in the first month of life

• Abnormal brain structures at birth

• Bleeding into the brain

• Abnormal blood vessels in the brain

• Serious brain injury or lack of oxygen to the brain

• Brain tumours

• Infections such as meningitis or encephalitis

• Stroke

• Cerebral palsy

• Mental disabilities

• Seizures occurring soon after head injury

• Family history of epilepsy or fever-related seizures

• Alzheimer’s disease

• Lengthy febrile seizures

• Alcohol or drug abuse

  
  

Diagnosis

A doctor diagnoses epilepsy based on symptoms, physical signs, and test results such as:

• Electroencephalogram (EEG)

• CT scan (Computed Tomography)

• MRI (Magnetic Resonance Imaging)

  
  

Proper diagnosis of both the type of epilepsy and the type of seizures is essential, as seizure types are often associated with specific forms of the disorder.

Treatment

Epilepsy may be treated with:

• Antiepileptic medical therapy (AEDs)

• Diet therapy

• Surgery

  
  

Medical Therapy

• Initial treatment for most patients with multiple seizures.

• Not always needed for a single seizure with low recurrence risk.

• Controls symptoms, does not cure the condition.

• Prevents seizures by reducing brain cell excitability.

  
  

Medication choice depends on:

• Seizure type and epilepsy type

• Side effects

• Patient’s age, gender, medical history

• Interactions with other medications

• Cost

  
  

Diet Therapy

Used in specific forms of epilepsy:

• Ketogenic diet: High-fat, adequate protein, low-carb diet started in hospital.

• Modified Atkins diet: Less restrictive, can be started as outpatient.

  
  

Both reduce seizures in about 50% of appropriate candidates, mostly children with refractory epilepsy who are not surgical candidates.

Medically-Resistant Epilepsy

About 30 percent of patients do not respond to standard therapy. These patients are treated at specialised epilepsy centres with a multidisciplinary team that may include:

• Adult and Paediatric Epileptologists

• Epilepsy Nurse Practitioners

• Neurosurgeons

• EEG Technicians

• Clinical Neuropsychologists

• Psychiatrists

• Radiologists (Neuro & Nuclear Medicine)

• Dietitians

• Neuroscience Nurses

  
  

Surgical Treatment for Epilepsy

Patients with refractory epilepsy may benefit from surgery, especially if seizures come from one area of the brain. The area must be removable without major neurological damage.

Pre-Surgical Evaluation

Consists of:

Phase I (Non-invasive)

• EEG

• Video-EEG Monitoring

• MRI

• PET scan

• SPECT scan

• Neuropsychological Evaluation

• Functional MRI

• Wada Test

Results help determine if all findings point to a single seizure origin (focus). If so, surgery may be an option.

Phase II (Invasive Monitoring)

If more clarity is needed, involves:

• Subdural Electrodes

• Depth Electrodes

• StereoEEG

• Functional Mapping

  
  

Surgical Procedures

Surgical Resections

• Lesionectomy: Removes abnormal tissue like tumours or cavernous malformations.

• Lobectomy: Removes a lobe (most commonly, temporal lobe).

• Multilobar Resection: Removes parts of two or more lobes.

• Hemispherectomy: Removes or disconnects one hemisphere.

  • Anatomic or Functional approaches.

    
    

Surgical Disconnections

• Corpus Callosotomy: Cuts the connection between hemispheres to reduce spread.

• Multiple Subpial Transections (MST): Disconnects neurons without removing tissue.

  
  

Stereotactic Radiosurgery

Focused radiation like Gamma Knife is used for deep-seated lesions visible on MRI. Generally used when surgery is too risky.

Neuromodulation

Vagus Nerve Stimulation (VNS)

• Electrodes implanted around vagus nerve, generator placed in chest.

• Reduces seizures in 40–50% of patients.

• Palliative, improves control, rarely eliminates seizures.

Responsive Neurostimulation (RNS)

• FDA approved in 2014.

• Implanted neurostimulator records brain activity and delivers impulses to interrupt seizures.

• Suitable for patients with one or two focal onset zones.

• Rarely results in seizure freedom but improves control.

  
  

Living and Coping with Epilepsy

Two life-threatening risks:

• Tonic-clonic status epilepticus: Prolonged seizure that requires emergency treatment.

• SUDEP (Sudden Unexplained Death in Epilepsy): Rare, more common in patients with frequent, uncontrolled seizures.

  
  

70–80% of people can successfully control seizures with treatment.Some rarely think about epilepsy apart from taking medication or doctor visits. Staying well-informed, positive, and engaged with a healthcare team is essential to leading a full, balanced life.

Conclusion

Epilepsy is a complex condition that requires a tailored, multidisciplinary approach to care. With proper diagnosis and treatment, many people with epilepsy can achieve excellent seizure control and lead fulfilling lives. At Singapore Brain Spine Nerves Center, our experienced team provides expert guidance and advanced treatments for epilepsy. If you or your loved one is experiencing recurrent seizures, seek professional evaluation to manage the condition effectively.

References and Acknowledgements

• American Association of Neurological Surgeons

• Singapore Brain Spine Nerves Center Protocols and Information