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First seizure

Medical Professionals

Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find the Epilepsy and seizures article more useful, or one of our other health articles.

Children and adults who have had a suspected first seizure should be referred urgently (within 14 days) to an epilepsy specialist (children do not routinely require referral following a febrile convulsion). 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 electroencephalograph (EEG) shows unequivocal epileptic activity or the individual or their family considers the risk of having a further seizure unacceptable1 .

A detailed history should be taken to exclude previous myoclonic, absence or focal seizures as patients with undiagnosed epilepsy may present with a single generalised tonic-clonic seizure2 .

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

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There is an 8-10% lifetime risk of one seizure and a 3% chance of epilepsy3 .

50% of patients with an apparent 'first seizure' have had other minor seizures, so the patient can be diagnosed as having epilepsy4 .

Risk factors

25-30% of first seizures have an underlying cause. Provoking factors include3 :

  • Fever.

  • Head injury.

  • Excessive alcohol intake; withdrawal from alcohol or drugs.

  • Hypoglycaemia; electrolyte disturbance.

  • Brain infection: meningitis, encephalitis.

  • Ischaemic stroke, intracranial haemorrhage.

  • Eclampsia.

  • Potentially proconvulsive drugs - eg, tramadol, theophylline, baclofen.

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


The clinical decision as to whether an epileptic seizure has occurred should be based on the combination of the description of the attack and different symptoms. Diagnosis should not be based on the presence or absence of single features. Prospective recording of events, including video recording and written descriptions, can be very helpful in reaching a diagnosis. When a child, young person or adult presents with a seizure, a thorough physical examination should be performed, including cardiac, neurological and mental state. An assessment of development is important for children presenting with a seizure5 :

  • Many people presenting with a dramatic first generalised tonic-clonic 'grand-mal' seizure have had previous, undiagnosed simple focal seizures or focal dyscognitive seizures, absence seizures or epileptic myoclonus.

  • A detailed history from the patient and any witness is essential.

  • Tongue-biting and postictal confusion suggest a seizure.

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Differential diagnosis


  • EEG:

    • 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. If the standard EEG is negative, sleep-deprived EEG will detect epileptiform discharges in an additional 13-31% of cases3 .

    • An EEG should be performed only to support a diagnosis of epilepsy where the clinical history suggests that the seizure is likely to be epileptic in origin. The EEG should not be used in isolation to make a diagnosis of epilepsy.

    • If an EEG is considered necessary, it should be performed after the second epileptic seizure but may, in certain circumstances as evaluated by the specialist, be considered after a first epileptic seizure. Following a first unprovoked seizure, unequivocal epileptiform activity shown on EEG can be used to assess the risk of seizure recurrence.

    • Photic stimulation and hyperventilation should remain part of standard EEG assessment but the patient should be made aware that such activation procedures may induce a seizure.

    • An EEG should not be performed in the case of probable syncope because of the possibility of a false-positive result.

    • An EEG may be used to help to determine seizure type and epilepsy syndrome.

    • Repeated standard EEGs may be helpful when the diagnosis of the epilepsy or the syndrome is unclear. However, if the diagnosis has been established, repeated EEGs are not likely to be helpful. Repeated standard EEGs should not be used in preference to sleep or sleep-deprived EEGs.

    • When a standard EEG has not contributed to diagnosis or classification, a sleep EEG should be performed.

    • Long-term video or ambulatory EEG may be used in the assessment when there are diagnostic difficulties after clinical assessment and standard EEG.

  • Neuro-imaging:

    • Neuro-imaging should be used to identify structural abnormalities that cause certain epilepsies. MRI is the imaging investigation of choice. MRI is particularly important in those:

      • Who have any suggestion of a focal onset on history, examination or EEG (unless clear evidence of benign focal epilepsy).

      • In whom seizures continue in spite of first-line medication.

    • Neuroimaging should not be routinely requested when a diagnosis of idiopathic generalised epilepsy has been made.

    • CT should be used to identify underlying gross pathology if MRI is not available or is contra-indicated. CT may be used to determine whether a seizure has been caused by an acute neurological lesion or illness.

  • Single proton emission computed tomography (SPECT).

  • Positron emission tomography (PET).

  • Other tests:

    • In adults, appropriate blood tests (eg, glucose, electrolytes, calcium, renal function, liver function and urine biochemistry) to identify potential causes and/or to identify any significant comorbidity should be considered.

    • A 12-lead ECG should be performed in adults with suspected epilepsy. In cases of diagnostic uncertainty, a referral to a cardiologist should be considered.

Neuropsychological assessment5

Neuropsychological assessment should be considered when it is important to evaluate learning disabilities and cognitive dysfunction, particularly in regard to language and memory. Referral for a neuropsychological assessment is indicated:

  • When the person with epilepsy is having educational or occupational difficulties.

  • When an MRI scan has identified abnormalities in cognitively important brain regions.

  • When there are reported memory or other cognitive deficits and/or cognitive decline.

Continue reading below


  • It is recommended that all adults having a first seizure should be seen as soon as possible by a specialist in the management of the epilepsies, to ensure precise and early diagnosis and initiation of therapy as appropriate to their needs.

  • Advise the family or carers of the person with suspected epilepsy how to recognise and manage a seizure and to record further episodes of possible seizures.

  • Essential information on how to recognise a seizure, appropriate first aid measures and the importance of reporting further attacks should be provided to a child, young person or adult who has experienced a possible first seizure and to their family/carer/parent as appropriate. This information should be provided while the child, young person or adult is awaiting a diagnosis.

  • Advise the person with suspected epilepsy to stop driving while waiting to see the specialist and to avoid potentially dangerous work or leisure activities - eg, avoid swimming and ensure bathing is undertaken with supervision.

  • Continued restrictions of potentially dangerous activities need to be assessed individually. Individuals should probably be suspended from working with dangerous machines for at least six months3 .

  • 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 anti-epileptic drug (AED) treatment.


Editor's note

Dr Sarah Jarvis, 4th June 2021

Updates to NICE guidance on epilepsy
In May 2021, the National Institute for Health and Care Excellence (NICE) updated its guidance on epilepsy5 . None of the non-drug recommendations has changed. The committee reviewed and amended recommendations on carbamazepine, gabapentin, lamotrigine, levetiracetam, oxcarbazepine, phenobarbital, phenytoin, pregabalin, topiramate and zonisamide in line with Medicines and Healthcare products Regulatory Agency (MHRA) updated safety advice on antiepileptic drugs in pregnancy6 .

In addition, the committee highlighted the risk of an irreversible effect on visual fields with use of vigabatrin and advised careful consideration of the risk:benefit ratio.

More information on the committee's recommendations is available from the Pre-pregnancy Counselling article.

See also the separate Anticonvulsants used for Generalised Seizures and Anticonvulsants used for Focal Seizures articles.

  • AED therapy should only be started once the diagnosis of epilepsy is confirmed, except in exceptional circumstances. AED therapy should be initiated by a specialist.

  • Treatment with AED therapy is generally recommended after a second epileptic seizure. AED therapy should be considered and discussed after a first unprovoked seizure if:

    • The child, young person or adult has a neurological deficit.

    • The EEG shows unequivocal epileptic activity.

    • The child, young person or adult and/or their family and/or carers consider the risk of having a further seizure unacceptable

    • Brain imaging shows a structural abnormality.

The patient's view on medication should be considered - eg, a women planning a pregnancy may choose to avoid AEDs in the short term but a person wishing to avoid recurrent seizures (for example, for driving) should be offered immediate treatment2 .

The decision to start AEDs should be made by both the patient and an epilepsy specialist. Whether to treat a single seizure or not is largely decided by the risk of further seizures. Estimates of recurrence risk vary. Highest recurrence rates (up to 90%) are seen in patients with epileptic discharges on EEG or structural cerebral disorder. Lowest rates (13-40%) are associated with acute symptomatic seizures (provoked) or patients with a normal EEG and no identifiable cause for seizures. Overall the risk is 30-40%; this is greatest in the first twelve months and falls to <10% after two years2 .

Although treatment with AEDs after a single seizure has a short-term effect in reducing the recurrence risk, this effect is not sustained. Early treatment with AEDs does not appear to alter the prognosis of epilepsy which is best predicted by the number of seizures in the first six months after diagnosis and response to first AED2 .


Following the first unprovoked epileptic seizure or solitary fit:

  • Any patient should be advised to stop driving and notify the Driver and Vehicle Licensing Agency (DVLA) and their motor insurance company following a seizure.

  • Group 1 (private car or motorcycle): six months off driving from the date of the seizure unless there are clinical factors or investigation results which suggest an unacceptably high risk of a further seizure, ie 20% or greater per annum.

  • Group 2 (large goods vehicle (LGV) or passenger carrying vehicle (PCV): five years off driving from the date of the seizure if the licence holder has undergone recent assessment by a neurologist and there are no clinical factors or investigation results (eg, EEG, brain scan) which indicate that the risk of a further seizure is greater than 2% per annum. They should have taken no anti-epilepsy medication throughout the five-year period immediately prior to the granting of the licence.


  • 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 seizure1 .

  • 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.

  • Low-risk patients with first seizures have no neurological deficits, normal MRI and EEG and a 35% risk of recurrence at five years; they are not usually offered treatment4 .

  • High-risk patients with first seizures have neurological deficit, MRI and/or EEG abnormalities and a 70% risk of recurrence at five years; they are offered treatment4 .

Further reading and references

  1. Epilepsy; NICE CKS, July 2019 (UK access only)
  2. Diagnosis and management of epilepsy in adults; Scottish Intercollegiate Guidelines Network - SIGN (2015 - updated 2018)
  3. Pohlmann-Eden B, Beghi E, Camfield C, et al; The first seizure and its management in adults and children. BMJ. 2006 Feb 11;332(7537):339-42.
  4. Angus-Leppan H; First seizures in adults. BMJ. 2014 Apr 15;348:g2470. doi: 10.1136/bmj.g2470.
  5. Epilepsies: diagnosis and management; NICE Clinical Guideline (October 2019 - last updated May 2021)
  6. Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review; GOV.UK - Medicines and Healthcare products Regulatory Agency (January 2021)
  7. Assessing fitness to drive: guide for medical professionals; Driver and Vehicle Licensing Agency

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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