First Glance

Ans. The basic tests are EEG, CT scan of the brain and MRI. Tests support the clinical diagnosis, help classify the type of seizures and syndrome, which in turn will help in predicting outcome and treatment, and lastly help to find a cause for the epilepsy.

Routine EEG cannot reliably prove or disprove the diagnosis of epilepsy.

It is positive in only about 60% of patients with newly diagnosed epilepsy. Also, a small proportion of the general population will have epileptiform abnormalities in the EEG. There are some situations in which EEG is especially useful in identifying epilepsy. One is petit mal or typical absence epilepsy and the other is non-convulsive status epilepticus where the patient presents with bizarre or confused behaviour. EEG may also be useful in identifying a structural abnormality. Sometimes EEG can be used as a screening procedure to detect a structural lesion, but in a country like India where cysticercosis and tuberculomas are common, it is better to do a CT scan straight away if this is suspected.

If the initial EEG is normal, a second EEG or an EEG after sleep deprivation will help increase the yield. Ambulatory EEG monitoring and videotelemetry are ways of obtaining an EEG over a longer period of time and in the case of the later, observing the pattern of EEG during an attack. Videotelemetry is useful in distinguishing between true seizures and pseudoseizures and between different types of seizures.

Neuroimaging (CT or MRI) does demonstrate a structural lesion. CT has a sensitivity of about 60% and MRI nearly 100%. Though CT is used, it detects lesions in only about 30% cases of partial epilepsy. MRI is particularly useful in identifying mesial temporal sclerosis, cavernomas, small arterio-venous malformations, low grade gliomas and congenital malformations. Although it is much more expensive, the information obtained makes it well worth while. General indications for neuroimaging are partial seizures, abnormal findings in neurological examinations, late onset epilepsy, and an EEG showing a one-sided, persistent abnormality. However, in countries such as India where infections are common, neuroimaging would be needed in most cases. This is often neither feasible nor practical.

2. What are the principles of treatment?

Ans.

• Use one appropriate first-line drug at any given time (Monotherapy)

  Carbamazepine is the first choice in partial seizures and secondarily generalized seizures.

  Phenytoin the first choice in partial seizures is cheaper, but avoid use in young men and women because of hirsutism, acne and gum hyperplasia.

  Phenobarbitone is also used for the same group. It is an effective drug but is less often used because it can produce lack of concentration and hyper activity in children and mental slowing at all ages. Sudden stopping of the drug can produce withdrawal symptoms, even seizures. However, it does not produce side effects in everyone. It is cheap and serious side effects are rare.

  Sodium valproate is the drug of first choice for primary generalized epilepsy.

• Start with a low dose; titrate the dose depending on the response.

• Use drug level monitoring as a guide for toxicity and to assess compliance. The so-called therapeutic range for each drug should only be used as a guide. It is useful for phenytoin because the relationship between dosage and serum concentration is unpredictable. Serum levels can be quite high on low doses or quite low on high doses. Treat the patient, not the drug level.

• Drug interactions occur with other drugs and other antiepileptic drugs.

• Seizure control and side effects should be the reasons for altering drug dosages, not the dosages themselves or the serum levels

• If seizures are not controlled with one first-line drug, then introduce another first-line drug and slowly withdraw the first. It may be necessary to have a combination of two first-line drugs.

• If this combination does not work, then the more effective first-line drugs should be continued and one of the following second-line drugs should be added.
  

  • acetazolamide
  • clonazepam
  • clobazam
  • lamotrigine
  • vigabatrin
  • gabapentin

   

• The last three drugs are 60-80 times as expensive as phenobarbitone or phenytoin
• Surgery can be considered for epilepsy resistant to drug treatment.

3. Which antiepileptic drug has the broadest spectrum?

Ans. Sodium valproate. It is useful in patients with generalised convulsions, both primary and secondary, simple absence attacks, juvenile myoclonic epilepsy and photosensitive epilepsy. Recently valproate has also been shown to be useful in the treatment of partial seizures both by itself and as an add-on therapy.

4. What drugs can be given by the relatives at home?

Ans. Per rectal diazepam

Lorazepam (Ativan) (special preparation) or ativapam can be placed between the cheek and the gum and is rapidly absorbed.

5. What can be given by a physician in an emergency?

Ans. Intravenous diazepam or intramuscular midazolam. (Both drugs require watching for respiratory depression.).

Intramuscular paraldehyde- (use a glass syringe only).

Phenytoin or phenobarbitone should NOT be given intramuscularly. However, a new preparation of phenytoin called fosphenytoin is now available for intramuscular use.

6. If I forget to take my tablets, what should I do?

Ans. If only one dose has been forgotten, the next dose can be doubled, except for carbamazepine where there should be a gap of a few hours between the regular dose and the extra dose.

7. How can I remember to take my tablets?

Ans. Take tablets at the same time each day. It should be a convenient time. Keep the day's tablets in a pill box so that at the end of the day you will know if your have taken them.

8. Can seizures get worse after starting treatment?

Ans. Yes. Occasionally, particularly if a drug such as carbamazepine, a drug of first choice in partial seizures, is used to treat someone with primary generalized epilepsy. Use sodium valproate when in doubt. In fact when the patient is between 5-15 years, has generalised tonic-clonic convulsions, without any clinically obvious focus, and EEG is unavailable, sodium valproate would be the drug of choice.

9. I always feel tired and sleepy. Is this normal?

Ans. It is not normal, however sleepiness is a common side effect. It should be the patient or parent who determines whether there is excessive sleepiness, rather than the doctor. Phenobarbitone and phenytoin are more likely to cause drowsiness than are the newer drugs. Also, drowsiness results when more than one drug is used and in higher doses.

10. Can drugs affect memory?

Ans. Yes, drugs can adversely affect memory. Polytherapy, the use of more than one AED, may impair the memory, as can the wrong drug dosage. Finally, the type of drug and particularly phenobarbitone or phenytoin, can cause poor memory function. Folic acid supplements may help reduce memory disturbance associated with phenytoin.

11. Why do some patients continue to have seizures despite treatment?

Ans. Several possible reasons.

• Inappropriate drug for that kind of seizure, e.g. giving carbamazepine for absence seizures or for juvenile myoclonic epilepsy. Seizures may even get worse.
• Incorrect dosage of correct drug.
• Irregular treatment.
• Underlying condition is getting worse.
• Patient has true drug resistant epilepsy (only diagnosed after trying other drugs).
• Patient may not have epilepsy at all. Exclude psychogenic epilepsy (or pseudoseizures) and cardiac arrhythmias.

12. What are the indications for follow-up by a neurologist?

Ans.

• Epilepsy worsening.
• Changes in seizures pattern.
• Side effects of treatment
• New symptoms.

13. What should I do if my child vomits?

Ans. If the vomit occurs within an hour or so of taking the medicine or if the medicine can be seen in the vomit, give another dose.

14. Can I get used to my drugs so that they are no longer effective?

Ans. Generally no. Growing children, pregnant women and adults who put on significant amounts of weight need to have dosages adjusted. The exceptions are nitrazepam, clonazepam and clobazam, which do tend to lose their effect over time, despite increasing doses.

15. My doctor prescribed drug X, but the chemist gave me drug Y. Should I take it?

Ans. It should be explained to the patient that drugs have a generic or chemical name and a trade name. Sometimes the chemist substitutes a drug with a different chemical name.

By and large, it is better to stick to the drug with the trade name which has been prescribed.

16. What other drugs should I take or not take, while on antiepileptic drugs?

Ans. In general, any other drug which may be necessary can be safely taken.

However, there are important exceptions.

• Phenobarbitone, phenytoin and carbamazepine interfere with oral anticoagulants e.g. warfarin, necessitating higher doses of warfarin and closer PT monitoring during the induction phase. These AEDs also reduce the efficacy of oral contraceptives, valproate does not do so.
• Isoniazid and phenytoin interact - sometimes necessitating a reduction in phenytoin dosage to avoid phenytoin intoxication.
• Aspirin and valproate may interact to cause bleeding.
• Carbamazepine and theophylline may interact reducing the efficacy of the former and resulting in seizures.

17. Can any drugs precipitate seizures?

Ans. Tricyclic antidepressants, phenothiazines, fluoroquinolones, isoniazid, high doses of penicillin, excessive insulin, oral hypoglycaemic agents, theophylline, are examples of drugs which may precipitate a seizure. Other drugs may provoke a seizures by interfering with antiepileptic drugs. Barbiturate and diazepam withdrawal can also provoke seizures.

18. Are other forms of treatment available?

Ans. There are a number of other treatments available. These include ayurveda, homeopathy, yoga, acupuncture, hypnosis, aromatherapy, and biofeedback. there is no scientific evidence of effectiveness for most of these.

19. What first-aid measures should be used if someone has a seizure?

Ans.

• Turn the patient on his or her side so that the tongue does not fall back and obstruct the airway. If there is vomiting, vomitus can then come out.
• Put nothing in the mouth, as it will not prevent biting the tongue and will only obstruct breathing or break a tooth.
• Put something soft under the person's head and neck.
• Time the fit. If it lasts more than 10 mins. or there are repeated fits, call a doctor and ambulance.

20. Should antiepileptic drugs be started after a single seizure?

Ans. After excluding any structural cause for the seizure, first, consider whether there was an avoidable precipitating factor, such as severe lack of sleep or excessive alcohol intake. If these can be avoided, treatment may be unnecessary. If the seizure had no obvious precipitating cause, then the following facts should be considered. In adults, as many as 78% of people who have had one seizure will have a subsequent seizure within the next 3 years. Of this 78% over half will suffer a second seizure within 4-6 weeks from the first one, and therefore treatment is necessary and should be started at the time of consultation if it is within this early period. If the consultation takes place longer than 6 weeks after the seizures, the decision to treat or not to treat should be made jointly.

21. Will the new vagal implant help me have better control of my seizures?

Ans. Long-term vagal nerve stimulation does reduce seizure frequency. It is considered to be safe and simple but is expensive. As with any new procedure only time will clarify its role vis-a-vis the new antiepileptic drugs and surgery.

22. What are the usual doses & serum levels of antiepileptic drugs?

Ans.

• Serum levels should not be estimated immediately after making dosage adjustments.
• If rapid antiepileptic effect is needed, an oral loading dose of phenytoin may be given.

* Antiepileptic drugs to be taken only after consulting your doctor

23. What are the side effects of common antiepileptic drugs?

Table : Side effects