First Seizure

Children and adults who have had a suspected first seizure should be referred urgently to an epilepsy specialist (children do not routinely require referral following a febrile convulsion).¹ Treatment is usually not recommended until after a second epileptic seizure but may be indicated after a first seizure if the individual has a neurological deficit, brain imaging shows a structural abnormality, the EEG shows unequivocal epileptic activity or the individual or their family consider the risk of having a further seizure unacceptable.¹

There are separate articles that cover Epilepsy in Adults, Epilepsy in Elderly People, Epilepsy In Children and Young People and Managing Epilepsy in Primary Care.

There is an 8-10% lifetime risk of one seizure and a 3% chance of epilepsy.²

Risk factors

25-30% of first seizures have an underlying cause. Provoking factors include:²

• Fever
• Head injury
• Excessive alcohol intake, withdrawal from alcohol or drugs
• Hypoglycaemia, electrolyte disturbance
• Brain infection
• Ischaemic stroke, intracranial haemorrhage
• Potentially proconvulsive drugs, e.g. tramadol, theophylline, baclofen

Seizures may be triggered by specific stimuli (e.g. stroboscopic lights, reading, severe psychological stress or sleep deprivation) in susceptible individuals with an underlying epilepsy disorder.

• The diagnosis can only be made from the history.
• Presentation with a first seizure is usually a convulsive seizure, either generalised or focal.
• Other seizure types such as absence or complex partial seizures typically occur several times before the person or family become concerned.
• Many people presenting with a dramatic first generalised tonic-clonic grand-mal seizure have had previous, undiagnosed simple or complex partial seizures, absence seizures, or epileptic myoclonus.
• A detailed history from the patient and any witness is essential.
• Tongue biting and postictal confusion suggests a seizure.

• Syncope may provoke a post-anoxic convulsion (convulsive syncope)
• Transient ischaemic attack
• Metabolic encephalopathy (including hypoglycaemia or electrolyte disturbance)
• Sleep walking
• Night terrors
• Complex migraines
• Cardiac arrhythmias
• Pseudoseizures (attacks resembling epileptic seizures but with psychological causes, and no EEG changes of epilepsy)

• The circumstances of a first seizure should direct investigations, e.g. a child with Type 1 diabetes should be assessed for hypoglycaemia.
• Electroencephalography (EEG)
  • Useful to suggest focal lesions, predict recurrence and indicate a specific epilepsy syndrome.
  • If performed within 24-48 hours of a first seizure, EEG shows substantial abnormalities in about 70% of cases. The yield may be lower with longer delays after the seizure.²
  • If the standard EEG is negative, sleep deprived EEG will detect epileptiform discharges in an additional 13-31% of cases.²
• MRI
  • Is the best method for structural imaging.
  • CT scan may not detect small tumours or other subtle pathologies.
  • The most common causes diagnosed with CT scans and MRI are cerebrovascular lesions, brain tumours and traumatic scar formations.

• Restrictions of potentially dangerous activities need to be assessed individually. Individuals should probably be suspended from working with dangerous machines for at least six months.²
• Driving is permitted after one year's freedom from seizures after an unprovoked seizure and on a case-by-case basis for provoked seizures.
• Commercial driving after an unprovoked seizure is usually not permitted until 10 years' freedom from seizure with antiepileptic drug treatment.

Drugs

• Antiepileptic drugs decrease but do not eliminate seizure recurrence and have no effect on long term remission.²
• Drug treatment may be justified when the risk of recurrence is high, when the risk of injury from a recurrent seizure is high (e.g. severe osteoporosis) or when the risk of economic hardship from a recurrence is high (e.g. loss of employment).
• If a child or adult is started on drug treatment following a first seizure, the decision about the length of treatment will depend on a number of factors, including the outcome of EEG and imaging investigations and the medical and social consequences of further seizure.

• Risk factors for seizure recurrence include:
  • Static or progressive brain abnormalities
  • Focal neurological findings
  • Focal or generalised epileptiform activity on EEG
  • Status epilepticus
  • Family history of epilepsy
  • Previous febrile seizures
• A first seizure caused by an acute disturbance of brain function (acute symptomatic or provoked) is unlikely to recur (3-10%).
• If a first seizure is unprovoked, 30-50% will recur. 60-70% of recurrences are within six months of the first seizure.¹
• After a second unprovoked seizure, 70-80% will recur, justifying the diagnosis of epilepsy.
• Seizures associated with reversible metabolic or toxic disturbances are associated with a minor risk of subsequent epilepsy.
• Seizures provoked by disorders that cause permanent damage to the brain, such as brain abscess, have a higher risk (10%) of recurrence.