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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.
Gabapentin |
‘ Add-on’ therapy in partial seizures. |
Dose related: Drowsiness, lethargy, nausea. |
Lamotrigine |
‘ Add-on’ and( in patients over 12 years) monotherapy in generalised tonic-clonic seizures( possible second choice after sodium valproate). Effective in absences with myoclonic seizures and partial seizures. |
Dose related: Sedation, unsteadiness and possibly worsening of seizures. Allergic: Rashes may occur in 10 % of patients, particularly if sodium valproate is taken simultaneously. To avoid rashes the drug must be introduced very gradually. |
Oxcarbazepine |
Primary generalised tonic-clonic seizures and partial seizures. |
Similar to carbamazepine, but less severe. |
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