The Specialist Forum May 2017 | Page 34

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NEUROLOGY

Epilepsy statistics

» Epilepsy affects one in every 100 people in South Africa , i . e . approximately half a million South Africans based on a total estimated population of 52 million .

» If every person with epilepsy has four immediate family members , at least another two million South Africans are affected by the condition .

» There are approximately 50 million people with epilepsy worldwide .

» Since 2004 SUDEP ( Sudden Unexpected Death in Epilepsy ) has increased by more than 100 % in South Africa .

» The overall risk of a child having unprovoked seizures is between 1 and 2 % of the general population . However , this increases to approximately 6 % if a parent has epilepsy .

» 75 % of people with epilepsy will experience their first seizure before the age of 20 .

» Up to 80 % of people with epilepsy will be able to control their seizures with medication .

» 1 in 20 people will have a seizure at some time in their lives . However , this does not mean that they have epilepsy ( which requires a specific diagnosis ).

» Slightly more men than women have epilepsy . for an epileptogenic zone is the finding that most often suggests increased risk for seizure recurrence . Diffuse abnormalities , such as hydrocephalus , may increase the risk by injuring the cerebral cortex ,” Ko said .

Abnormalities on an EEG may include any of the following :

» Epileptiform discharges

» Focal slowing

» Diffuse background slowing

» Intermittent diffuse intermixed slowing .

Epileptiform abnormalities and focal slowing are the EEG findings associated with the highest risk of seizure recurrence . Nevertheless , even a normal EEG does not eliminate recurrence risk .

The risk of recurrence in a person with one generalised tonic-clonic seizure , a normal EEG , a normal brain MRI , and no evidence of focal onset is about 15 %; in this case , the patient is not treated . If a patient has all risk factors , the risk is approximately 80 %, and the patient is treated .

“ The major unresolved question is how to treat patients with one abnormality , whose recurrence risk is 30- 50 %. One approach is to base the decision on a discussion with the patient that includes the risk of seizure recurrence , the risk of toxic effects from the anticonvulsant , and the benefits of avoiding another seizure .

“ The clinician should also describe seizure precautions , including not driving for a specific time . Treatment with anticonvulsants does not alter the natural history of seizure

Active ingredient Epilepsy / seizure type Side effects

Carbamazepine Simple and complex partial seizures , generalised tonic-clonic seizures .

Clobazam ‘ Add-on ’ in tonic-clonic , myoclonic and partial epilepsies . Effective in catamenial epilepsy ( menstrual seizures ).

Clonazepam Second or third choice for myoclonic seizures . Effective “ add- on ” for tonic-clonic and absence seizures . May be used in status epilepticus .

Diazepam

Drug of choice in status epilepticus ( rectally or intravenously ). Rarely used in regularly in tablet form .

Ethosuximide First or second choice for typical absence seizures . May be effective in myoclonic seizures . Not effective in generalised tonic-clonic seizures .

Dose related : Nausea , double vision , unsteadiness . Allergic : Rash , reduced white blood cells count , increased appetite ( rarely ), no obvious effect on concentration , memory or behaviour .

Dose related : Drowsiness and lethargy . Drug loses effect over time despite increasing dosage .

Dose related : Drowsiness , lethargy , drooling and hyperactivity in children . Drug loses effect over time . May cause inflammation of the veins .

Dose related : Drowsiness , lethargy , drooling and hyperactivity in children .

Dose related : Drowsiness , nausea , vomiting , headache , irritability . Allergic : Rashes .

Phenobarbitone

Phenytoin

Effective in generalised tonic-clonic , myoclonic and partial seizures . Effective in status epilepticus .

Second or third choice in generalised tonic-clonic seizures . Effective in partial and myoclonic seizures . Drug of choice in status epilepticus .

Sodium valproate First choice in primary generalised tonic-clonic seizures , typical absence , atonic and myoclonic seizures and photosensitive epilepsy . Effective in partial seizures ( second choice after carbamazepine ).

Topiramate

Prescribed for partial seizures with or without secondarily generalised seizures , inadequately controlled by conventional first-line drugs .

Valproic acid Similar to sodium valproate Similar to sodium valproate

Dose related : Drowsiness , lethargy , unsteadiness . Chronic use : Tolerance and impairment of concentration and memory , slowness in activities . Withdrawal seizures if discontinued too quickly .

Dose related : Nausea , vomiting , unsteadiness , slurred speech . Allergic : Rash , hepatitis ( inflammation of the liver ), swelling of lymph glands . Chronic use : Gum , swelling , acne , hairiness ( face and body ), folate deficiency , involuntary movements , rickets .

Dose related : Tremor , sedation , restlessness , increased appetite . Allergic : Stomach irritation , inflammation of liver and pancreas . Chronic use : Hair loss ( usually transient ), weight gain , low platelets in blood ( may cause excessive bleeding Should not be taken during pregnancy .

Dose related : Drowsiness . Loss of appetite and weight may occur .

34 | May 2017

The Specialist Forum | Vol . 17 No . 4