Key questions in diagnostic evaluation of patients presenting with a seizure include is it an epileptic seizure or a nonepileptic mimic and, if epileptic, what are its features? Few investigations provide conclusive diagnostic results, and assessment is largely clinical. The cause of the seizure and likelihood of recurrence are important considerations when deciding on management.
- Many patients who present for the first time with a tonic-clonic seizure have had previous nonconvulsive seizures and have epilepsy.
- The diagnosis of epileptic seizure should never be assumed without a supporting history because several nonepileptic disorders, including syncope, paroxysmal movement disorders and psychogenic nonepileptic seizures, can mimic epileptic seizures.
- Electroencephalography is an important diagnostic test for patients presenting with seizures; the presence of interictal epileptiform discharges strongly supports a diagnosis of epileptic seizures, although normal results do not exclude a diagnosis of epilepsy.
- CT is useful only in the acute setting when looking for structural lesions such as a stroke, abscess, haematoma or tumour.
- Focal seizures and evidence of neurological dysfunction are predictive of seizure recurrence.