Epilepsy Diagnosis and Management

Epilepsy diagnosis and management follows a clear sequence: exclude seizure triggers, investigate with EEG and MRI, treat with antiepileptic drugs, and consider surgery only when medication fails. In Dr. Dinesh Rattnani's experience, 60 to 70% of patients become seizure-free on drugs. The remaining 20 to 30%, and possibly up to 40%, develop drug-resistant epilepsy, for whom surgery or brain stimulation can change the course of the disease.

Dr. Dinesh Rattnani, Senior Director - Neurosurgery, Neuro Critical Care & Spine Surgery, Max Super Speciality Hospital, Noida, India, approaches epilepsy as a neurosurgeon: his question is not which drug to prescribe next, but when medication has genuinely failed and what an operation can realistically offer. His answer is a disciplined sequence. Exclude the triggers, investigate properly, give medication a full trial, and operate only when the investigations point clearly to a target or when a patient's seizures leave no other option.

What epilepsy is, and what a seizure does

Epilepsy is a long-term, chronic disease of repeated seizures caused by abnormal electrical signals produced by damaged brain cells. A seizure is a burst of uncontrolled electrical activity within those cells. Depending on where it starts and how far it travels, a seizure can alter muscle power and control, sensation, emotion and behaviour.

Two features of seizures shape everything that follows in management. First, many seizures begin at a focal point, and some of these then spread to become generalised; others are generalised from the outset, involving both hemispheres from the start. Second, the focal point is often, but not always, a visible abnormality in the brain. Where it is visible, it can sometimes be removed. Where it is not, treatment has to work on the spread or on the excitability of the brain as a whole.

Dr. Rattnani notes that idiopathic epilepsy, in which no structural cause is found, is the most common type. These patients have a normal MRI of the brain and still have epilepsy, and their treatment is medical.

Epilepsy management starts with medication

Antiepileptic drugs are primarily prescribed by physicians and neurologists, and there is a long list to choose from. Dosing follows body weight. For a patient whose EEG (a recording of the brain's electrical activity) and MRI are both normal, Dr. Rattnani's advice to referring doctors is to continue with the standard drugs, such as levetiracetam, phenytoin and sodium valproate, and to manage conservatively with up to two or three drugs at maximal doses. Most patients respond well.

The choice of drug depends on the type of epilepsy: generalised tonic-clonic seizures, focal seizures with secondary generalisation, or atonic seizures (a sudden loss of muscle tone). In his ranking:

• Sodium valproate and levetiracetam both have a broad spectrum and sit first and second, so either can be started. His own preference is valproate as the drug of choice.
• Carbamazepine is slightly preferred for focal seizures with secondary generalisation, although valproate also works well there.
• Levetiracetam is what his team normally uses after surgery.
• Lacosamide is emerging as an add-on drug, not as first-line therapy.
• Perampanel, in his view, is mainly useful in patients with brain tumours and has shown promising results where brain tissue is damaged.

His top three, taken together, are levetiracetam, valproate and carbamazepine. One safety point applies to any prescriber: valproate is avoided in girls and women who could become pregnant unless other treatments are unsuitable, because exposure in pregnancy carries a high risk of birth defects and developmental disorders.

When medication is not enough

Dr. Rattnani defines drug-resistant epilepsy as seizures that continue despite a minimum of two drugs, each at its maximum allowed dose. The International League Against Epilepsy (ILAE) uses a closely related definition: failure of adequate trials of two tolerated, appropriately chosen and appropriately used antiepileptic drug schedules to achieve sustained seizure freedom.

The label is applied only after triggers such as stress, lack of sleep, alcohol and fever have been excluded and corrected. This is the point at which the neurosurgeon's role begins. The trigger checklist, the investigations that decide surgical candidacy and the referral criteria are covered in drug-resistant epilepsy: workup, EEG and MRI concordance and when to refer.

Three surgical approaches when medication fails

Surgery for drug-resistant epilepsy falls into three types, each aimed at a different part of the problem.

1. Resective surgery removes the abnormal tissue that generates the seizures: a sclerosed mesial temporal lobe, a tumour such as a glioma or meningioma, a depressed bone fragment, scar tissue, or neurocysticercosis cysts. Lesionectomy and lobectomy belong here, and they can give a seizure-free outcome.
2. Disconnection surgery accepts that the seizure starts somewhere but stops it spreading. Corpus callosotomy, subpial transection and hemispherectomy create barriers so that activity starting at one point cannot travel to the whole brain.
3. Neuromodulation leaves the source in place and modulates the activity of the neurons. Vagal nerve stimulation and deep brain stimulation are the two options.

Which family fits depends on the investigations. A patient whose MRI and EEG point to the same lesion is a candidate for resection, with very good results. A patient with a completely normal MRI can still be a candidate for resection if video EEG, functional imaging or intracranial EEG localises a single focus, but the chance of seizure freedom is lower; for many such patients, neuromodulation is the surgical option. The procedures, the surgical technique and how complications are avoided are set out in types of epilepsy surgery: temporal lobectomy, disconnection and brain stimulation.

Epilepsy surgery success rates and realistic outcomes

Dr. Rattnani is direct about expectations. The goal is to make every patient seizure-free, but the team may or may not succeed, and he cannot guarantee that a patient will become seizure-free or come off antiepileptic drugs. His own figures:

• In about 80% of his patients, surgery achieves the desired result, or at least allows the antiepileptic drugs the patient was taking to be reduced.
• In 90 to 95% of cases, he is confident the surgery will do no harm.
• Complications, from infection and bleeding to weakness and memory problems, occur in 5 to 10% of cases, depending on the site of the operation.

Outcomes depend on the underlying problem. The results of surgery for mesial temporal sclerosis, lesionectomy, vagal nerve stimulation and deep brain stimulation are good and satisfactory. Hemispherectomy carries the most complications and is held in reserve for patients who have no other choice. Even where seizures are not abolished, the purpose of surgery is to improve the quality of life the patient is living now, often with the help of continuing medication.

Epilepsy medication after surgery: tapered, not stopped

Surgery does not end drug treatment. These are drug-resistant patients who were having seizures despite medication, so the drugs are not withdrawn the day after the operation. Dr. Rattnani's sequence is:

1. Continue the same drugs for the first few days.
2. After 10 to 15 days, begin slowly withdrawing one drug, provided the patient has no seizures.
3. Keep the patient on a single drug for at least a year, during which the patient must remain seizure-free.
4. Consider stopping medication completely only at around two years.

Most patients report that they feel better after surgery, particularly after surgery for mesial temporal sclerosis. Hemispherectomy is the exception: it does not necessarily mean the patient comes off antiepileptic drugs, although with the drugs, seizures that were previously uncontrolled may then be controlled.

A multidisciplinary decision, not a surgeon's decision

Epilepsy surgery needs a multidisciplinary team. At Max Super Speciality Hospital, Noida, each case is discussed first with the neurologists, then with the neuropsychiatrist and the psychologist. Only when they give a green signal does the team proceed. Dr. Rattnani's reasoning is that a complication in this setting can be disastrous, because it can reduce a patient's quality of life rather than improve it, so the decision to operate is shared across every specialty that assesses the patient.

Where epilepsy surgery is done

Epilepsy surgery is not confined to any one country. It is a standard procedure practised wherever neurosciences centres exist, including the United States, the United Kingdom and Canada. By Dr. Rattnani's estimate, it is performed at more than 40 to 50 centres across India. Robotic assistance is not part of epilepsy surgery at his centre: in his department, robotics is used only to place spine screws, and no brain surgery is performed with the robot.

The questions doctors raised during the session, from hemispherectomy to post-operative care, are answered in the live discussion with Dr. Rattnani. For other procedures in neurosurgery, see the cost of brain and neurosurgery procedures.