The Sydney Neuro-Oncology Group (SNOG)

Notes from Brain Tumour Support Group Presentation 30 October 2002 presented by Dr Geoff Herkes, Neurologist

ABOUT SEIZURES

Approximately 10-20% of patients with a brain tumour will have a seizure. Sometimes it is the first symptom of a brain tumour

Definitions:
- Epilepsy is defined as more than two seizures.
- 5-7% of Australians will have one seizure in their lifetime
- 1-2% of Australians have epilepsy

What is a seizure?
- A sudden firing of neurons in the brain
- Symptoms depend on where in the brain seizure activity occurs.
- Abnormal firing is seen on electroencephalogram (EEG).

Epilepsy is the second most common condition neurologists see (most common is headache).

Partial seizure:
- Discharge is localised. Temporal lobe is the most common site of discharge.
- Some signs of temporal lobe seizure activity include:
   > experiencing déjà vu (sense of familiarity with unfamiliar events).
     Normal to experience this very occasionally but 1-2/week is cause for concern.
   > Jamais vu (sense of unfamiliarity with familiar events)
   >Epigastric sensations, unpleasant smells and/or feeling of impending doom.
- Signs of occipital lobe seizures include visual symptoms (eg swirling colours).
- With partial seizures may remain conscious (simple partial) or lose memory (complex partial)

Generalised Seizure:
- Discharge initially localised then spreads to include both sides of the brain

Do these seizures damage the brain?
- Partial seizures – no
- Generalised seizures that are > 5 min can damage the brain because of lack of oxygen. Need to call ambulance if the convulsing lasts > 3 - 5 minutes.
- 99.9% of seizures do stop within 5 minutes.

Primary generalised seizures or 'absence seizures' commonly occur in children (called petit mal) and characterised by brief episodes of absences or “trances”. Seems like the child is daydreaming. Can have several hundred in one day. Use different drugs to treat this type of seizures.

Other conditions that look like seizures but are not seizures
- syncope
- cardiac arrhythmia
- brain ischaemia or transient ischaemia attack
- hysteria/malingering

Terminology for seizures/epilepsy has changed over the years.

* Good way to determine if consciousness is impaired : if you talk to the person during the seizure they will remember what you said when the seizure is over (simple partial)

* Continual seizures called 'status epilecticus'

Other classification systems:

Partial Seizures                          Generalised Seizures

Simple                                          Absence
Complex                                       Myoclonic
                                                        Tonic-Clonic
                                                        Atonic

 Old vs New Technology

- With tonic-clonic seizure person may turn blue as they don’t breathe during the tonic phase and their limbs stiffen. During the clonic phase they will breathe but their limbs will start to jerk. This is followed by exhaustion and a period of confusion which lasts approximately 20 minutes. They can also be irritable during this phase. Referred to as 'post-ictal'.

First aid for generalised tonic-clonic seizure includes:
- Don’t panic
- Loosen ties, any tight clothing
- Remove person from anything that will cause injury or remove objects from near person that may cause injury
- Do not try to put anything in the person’s mouth. Remember it is impossible to swallow tongue. The person may bite their tongue during the seizure.
- Turn person into recovery position (sidelying, pillow to support back). This prevents mucous from going into the lungs. May be difficult to position during the tonic-clonic phase so may need to wait.
- If in doubt call an ambulance ‘000’.

Some types of seizure activity such as abnormal sensations such as smell and taste does not show up on EEG.

Individualised Therapy for Seizures

Drugs we use for
1. Generalised seizures:
- Epilim (Valproate)
- Ethosuximide (Zarontin)

2. For Partial Seizures (with or without generalization)
- Carbamazepine (Tegretol)
- Phenytoin (Dilantin)
- Epilim (Valproate)

There are several new drugs including
- Neurotin (gabapentin)
- Lamictal (lamotrigine)
- Topamax (topiramate)

Concepts of Drug Therapy
- With drugs such as Dilantin need regular blood tests to determine level of drug in blood is therapeutic. This may happen frequently at first then as stable only every 6-12 months.
- Liver function tests are done to ensure drug is not causing liver enzyme change. Doctor would expect liver function tests to be a bit abnormal but any grossly abnormal tests would be cause for concern. Dilantin and Tegretol may alter liver enzymes.
- Alcohol with anticonvulsants: most important is not to binge drink. Small amount is fine eg one glass of wine. May find have a much lower tolerance for alcohol when on anticonvulsants.

Lifestyle factors
- Sleep deprivation is a big trigger for seizures.
- Infections eg vomiting and diarrhea can trigger seizures. May need to take an additional (usually half normal dose) of medication if you are concerned that you have not absorbed the drug because of vomiting. Good idea to contact doctor if have had bad bout.

Driving
RTA has a booklet with guidelines to follow re driving and seizures.
- After seizure can’t drive for three months. Question: Does ‘bad smell’ type of seizure count? Answer: No.
- After brain surgery can’t drive for three months
- Epilepsy that is hard to control - usually two years off driving
- When you resume driving have someone go with you the first few times as a safety precaution.

Memory may be affected after a seizure. Usually recovers completely after about one week.

Status Epilepticus:
Seizures don't stop. Need to receive emergency care, usually drugs such as valium. Ambulance needs to be called. Call 000.

Question: Why do generalised seizures often occur at night?
Answer: Related to second stage sleep. May not be aware that had seizure if no one with you. Clues include bet wet due to incontinence of urine, bitten tongue or feeling abnormally tired on awakening.

Question: Will anticonvulsant drugs affect normal brain?
Answer: Drugs target brain with seizure activity mostly. They can however affect normal brain. This is experienced as being a bit slower and maybe memory not as good. However, sometimes these symptoms can mean that the drug level is too high.

Question: Do complex partial seizures cause scar tissue in brain?
Answer: No.

Question: After brain tumour surgery if you are seizure free how long do you stay on drugs?
Answer: Usually 3-6 months. 10% of people with brain surgery will have a seizure. After you come off anticonvulsants can't drive for three months. This is to ensure there is no risk if occur seizures during that period.

Question: Does oxygen settle a seizure?
Answer: May help. But not feasible to have oxygen available at home.

Question: What about complementary medicines and seizures/anticonvulsant medications?
Answer: Vitamins are OK. Brahmi interacts with Dilantin. Gingo Biloba may alter some drugs. The Adverse Drug Reactions Committee (ADRAC) of the Therapeutic Goods Association (TGA) provides some details. Phone 1 800 020 653 / www.health.gov.au/tga or email at adrac@health.gov.au

Complementary medicines are now regulated so can't claim to do something they have not been proved to do. Still can make broad claims but not specific claims.

Question: What about swimming?
Answer: Swim with someone. Don't swim alone. Good advice for anyone whether you have seizures or not.
Baths may not be a good idea. Don't take a bath unless someone is in the house at the time. When showering turn on cold water first then hot as a safety measure.

Riding bicycles – the same rules as for driving a car.

If seizure pattern changes it is probably a good idea to see doctor.