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ReettaKälviäinen
EsaMervaala
SariAtula
AnteroPilke
UntoNousiainen

Examining a Patient after an Epileptic Seizure

Essentials

  • The first physician attending to the patient should establish and record the course of the seizure, including pre-ictal as well as post-ictal signs and symptoms.
  • Eyewitness accounts of the event are of utmost importance and should be obtained immediately after the seizure, e.g. from a person accompanying the patient who saw the event, either in person or by telephone. This may be crucial for diagnosis.
  • The patient should be referred for neurological investigations for the confirmation of the diagnosis and for aetiological studies (in adult-onset epilepsy, a brain tumour should be considered as a possible cause).
  • Brain imaging should be arranged quickly, but not necessarily as an emergency.
  • The diagnostic approach after a first seizure associated with alcohol withdrawal should be the same as after an epileptic seizure, i.e. a single brain scan is warranted.
  • If an episode of unconsciousness is not clearly epileptic in nature, an adult patient will often primarily need cardiac investigations.

Epidemiology and definitions

  • It has been estimated that 8-10% of the general population will experience at least one epileptic seizure during their lifetime, and 4-5% will develop epilepsy.
  • Less than 1% have active epilepsy, i.e. need continuous pharmacological treatment.
  • An epileptic seizure is a transient disturbance in brain function that is due to abnormal, excessive or synchronized electric neuronal activity in anatomic areas of the brain of varying size.
  • Epilepsy is a brain disease in which the brain has a chronic tendency to cause epileptic seizures and patients may additionally have problems in neurological, cognitive, mental or social performance in consequence of the disease.
  • If the seizure is associated with some immediate, exceptional provoking factor (brain injury, brain disease or systemic disorder), it should not be treated as epilepsy if the provoking factor can be otherwise eliminated or treated.
  • To diagnose epilepsy the patient must have had at least one epileptic seizure and, in addition, a chronic factor predisposing to seizures must have been observed in the brain. A diagnosis is usually only made when the tendency to have recurrent seizures has been shown, i.e. the patient has had at least two seizures.

Aetiology

  • Genetic cause
    • The epilepsy is caused by a diagnosed or assumed genetic disorder, and epileptic seizures are the main symptom of the disease.
  • Structural or metabolic cause
    • A structural or metabolic state or disease known to be associated with an increased risk of epilepsy may be identified behind the epilepsy. Such states or diseases may be
      • congenital, such as aberrant cerebral cortical development
      • acquired, such as following trauma or CNS infection
      • associated with other neurological conditions, such as disorders of cerebral circulation, brain tumours, many complex syndromes.
  • Unknown cause
    • The cause of the epilepsy may be unknown at the time of assessment. However, there may be a currently unidentified genetic or structural cause. Therefore in these cases, the aetiology should be regularly reassessed.

Seizure types

  • For classification and terminology: see http://www.ilae.org/Visitors/Centre/Documents/OrganizationEpilepsy.pdf.
  • The symptoms of focal seizures point to damage in a limited area of the brain and reflect dysfunction of that area. The majority of adult-onset epilepsies belong to this group.
    1. Focal seizures with retained consciousness or awareness (earlier: simple partial seizures), prodromal symptoms (aura)
      1. Motor symptoms: contractions of the limbs, deviation of the gaze or the posture of the head or body, vocalisations or speech arrest
      2. Sensory symptoms: visual, auditory, olfactory, gustatory, vertiginous
      3. Autonomic symptoms, i.e. symptoms of the autonomic nervous system: palpitations, abdominal sensations, sweating, flushing, pallor, pupil dilatation, salivation, sexual reactions
      4. Mental symptoms: expressive language disturbances, memory distortion, déjà-vu phenomena, disturbance of comprehension, fear, anxiety, euphoria, hallucinations
    2. Focal seizures with impaired consciousness or awareness or responsiveness (earlier: complex partial seizures)
      1. The seizure may start with one or more of the above-listed simple symptoms followed followed by impaired consciousness, or the episode may begin directly with impaired consciousness.
      2. In addition, there may be automatisms, i.e. coordinated or partially coordinated, elaborate, nonpurposeful movements or behaviours of which the patient is not aware, such as lip smacking, swallowing, bustling around or aimless walking, picking at clothes, undressing, etc.
    3. Focal seizures evolving to a bilateral convulsive seizure (earlier: secondarily generalized seizures)
      1. Both types of focal seizures may evolve to loss of consciousness and convulsions as the discharge spreads to involve both cerebral hemispheres.
  • Generalized seizures: a sudden disturbance in the electrical activity of the brain that occurs simultaneously in both cerebral hemispheres. The seizure starts with a loss of consciousness and the convulsions are symmetrical on both sides from the onset. Generalised seizures include:
    • tonic-clonic seizures, i.e. seizures accompanied by loss of consciousness and convulsions but with no pre-ictal symptoms
    • brief absence seizures starting to occur in childhood (brief episodes of impaired consciousness starting to occur in adulthood are usually of focal origin).

Patient history

  • Predisposing factors (sleep-deprivation, fasting, alcohol ingestion especially alcohol withdrawal after prolonged consumption Neurological Disorders and Alcohol, medications, flickering light)
  • What was the patient doing at the onset of the seizure?
  • Were there any pre-ictal symptoms or sensations?
  • Did the patient remain conscious during the seizure?
  • Eye-witness description of the seizure
  • Recovery from the seizure (rapid or gradual, orientation, memory impairment)
  • Urinary or faecal incontinence?
  • Have there been more minor seizure symptoms in the past for which the patient has not sought medical assistance (e.g. a symptom at the beginning of the tonic-clonic seizure that has occurred previously without evolving to a more major seizure)?

Clinical findings

  • If the physician is able to examine the patient during the seizure or immediately thereafter, it is important to note
    • orientation, confusion, memory of the seizure
    • the presence of injuries, bruising, grazes, joint dislocations
    • whether the patient has bitten his/her tongue
    • whether there are unilateral neurological symptoms (transient post-seizure weakness of a limb affected by seizure activity, i.e. Todd's paralysis, indicates epilepsy of focal origin)
    • pupillary reaction, positive Babinski sign
    • whether there is evidence of excessive use of alcohol or other intoxicants prior to the seizure
    • blood pressure, pulse, evidence of cardiovascular aetiology.
  • If the physician does not see the patient until several days after the seizure, no significant clinical findings are usually noted. However, it is advisable to look for unilateral neurological symptoms and signs of increased intracranial pressure.

Laboratory tests

  • Blood count, plasma calcium, sodium, potassium, creatinine and creatine kinase, blood glucose
  • Serum TSH
  • ECG (conduction times must be measured)

Additional investigations in a neurology unit

  • The aim of the diagnostic workup is to confirm whether the seizures experienced by the patient are epileptic or non-epileptic episodes, to define the type(s) of seizures in question, to identify the epilepsy syndrome and to establish whether the epilepsy is caused by a structural cerebral defect.
  • Optimal management is based on exact diagnosis, i.e. the type of seizures as well the type of epilepsy or epilepsy syndrome should be identified.
  • EEG (electroencephalogram)
    • The optimal time is as soon as feasible after the seizure; an awake EEG should be recorded first, followed by a sleep EEG if needed. Irritative EEG findings (spikes, sharp waves, spike-slow wave complexes) are strongly suggestive of epilepsy. A normal inter-ictal EEG does not rule out the possibility of epilepsy.
  • An MRI scan of the brain is the most recommended imaging study in epilepsy.
    • MRI scanning is able to reveal aetiological factors not detectable with CT scanning of the brain, such as aberrant cerebral cortical development.
    • A CT scan is recommended in acute situations and in situations where MRI scanning is contraindicated.
    • An MRI is indicated if the aetiology of epilepsy has not been confirmed with a CT scan obtained in an acute situation or with other investigations.
  • If the MRI findings are normal and seizures keep recurring, repeat MRI using a special examination protocol should be performed in a unit specialized in epilepsy. Repeat imaging often shows changes not observed in routine imaging.
  • Special investigations required in problematic cases, such as in treatment-resistant epilepsy, workup of atypical seizures and when surgical management is being considered (see Clinical Neurophysiology in Diagnostics):
    • continuous ambulatory EEG monitoring with the aim of obtaining an EEG during a seizure
    • EEG video-telemetry with the aim of obtaining an EEG with simultaneous video picture.

Cardiological investigations

  • Continuous ambulatory ECG monitoring and tilt testing should be considered for the purpose of differential diagnosis in cases where the seizures are not clearly epileptic in nature and where neurological investigations fail to show a clear epileptic aetiology.

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