Seizure in Adults

Background

• A seizure is a transient clinical manifestation of abnormal electrical brain activity.
• Seizures can occur:
  • due to acute precipitating factors such as toxins, medications, drugs of abuse, or metabolic factors (provoked seizure) or acute brain insults (acute symptomatic seizure)
  • without acute precipitating factors (unprovoked seizure)
• Epilepsy is defined as:
  • 2 or more unprovoked or reflex seizures occurring > 24 hours apart
  • or a single unprovoked (or reflex) seizure and high risk of recurrence (≥ 60%) over the next 10 years
  • or a diagnosis of an epilepsy syndrome
• Epileptic seizures may be:
  • generalized (involving bilateral brain networks) with clinical types including tonic, clonic, myotonic, atonic, tonic-clonic, and absence
  • focal (originates within brain networks limited to 1 hemisphere) and can be further qualified by whether they have:
    • impairment of consciousness or awareness
    • phenomenology which can have motor or non-motor (autonomic, behavioral, cognitive, emotional, or sensory) manifestations
    • may at times evolve to bilateral convulsive seizures

Evaluation

• The routine neurodiagnostic evaluation of adults with an apparent unprovoked first seizure should include brain imaging (with computed tomography [CT] or magnetic resonance imaging [MRI]) (Strong recommendation) and an electroencephalogram (EEG) (Strong recommendation).
  • CT is useful in adult patients in the acute setting presenting with:
    • first seizure (Weak recommendation)
    • focal seizure onset, predisposing history, or an abnormal neurologic examination (Strong recommendation)
    • comorbid AIDS (Weak recommendation)
  • MRI
    • if there is sufficient concern for a focal abnormality, can be used to detect subtle lesions (low-grade gliomas, hippocampal sclerosis, cavernous malformations, malformations of cortical development)
    • epilepsy protocol-specific MRI read by an expert neuroradiologist can increase sensitivity for subtle lesions (especially focal cortical dysplasia and hippocampal sclerosis)
• EEG is useful in suspected first seizure for predicting recurrence and for seizure classification.
  • Emergent EEG should be obtained in patients suspected to be in nonconvulsive or subtle convulsive status epilepticus, patients who are receiving a paralytic medication, or those who are in a drug-induced coma (Weak recommendation).
  • Continuous EEG may be better at detecting nonconvulsive seizures than routine EEGs
• Other investigations should be guided by the clinical history and presentation but potentially helpful tests may include:
  • complete blood count with differential
  • electrolytes, glucose
  • toxicology screening
  • lumbar puncture
    • in immunocompromised patients (Strong recommendation)
    • in cases with concern for meningitis, encephalitis, or subarachnoid hemorrhage
  • pregnancy test in women of childbearing age (Strong recommendation)
• Syncope is an important differential diagnosis to consider. A history of presyncope, triggering by orthostasis or a situational trigger (for example, fear, pain, medical procedures, or micturition), and lack of a postictal state may be more suggestive of this diagnosis.
• Complicated migraine and psychogenic seizures are additional important differential diagnostic considerations.

Management

• Initial management of a convulsive seizure includes airway assessment, protection, and ensuring hemodynamic stability.
• Patients with an unprovoked new-onset seizure who have returned to baseline can be discharged from the emergency department (Weak recommendation).
• Hospital admission should be considered in all seizure patients who have any of the following:
  • a cause of the seizure that requires urgent treatment (such as such as infection, encephalitis, metabolic disturbance, toxicity, or hemorrhage)
  • recurrent seizures
  • a fever
  • impaired consciousness or focal neurologic deficits
  • inadequate social support
• Emergent therapy is indicated for recurrent or prolonged seizures lasting ≥ 5 minutes or tonic-clonic seizures lasting ≥ 2 minutes.
  • Emergent initial pharmacologic therapy is a short-acting benzodiazepine, with IV lorazepam 0.1 mg/kg IV (maximum 4 mg/dose; may be repeated in 5-10 minutes) being the preferred agent (Strong recommendation).
  • see Status Epilepticus in Adults for further details.
• Medications for seizure prevention with confirmed diagnosis of new-onset epilepsy:
  • narrow spectrum agents such as carbamazepine, oxcarbazepine, phenytoin, or lacosamide typically effective for focal epilepsy.
  • broad spectrum agents such as lamotrigine, levetiracetam, topiramate, valproate derivatives, or zonisamide typically effective for focal and generalized epilepsy.
  • careful consideration should be taken for which agent to use depending on type of seizure:
    • narrow spectrum agents may worsen myoclonic and absence seizures in genetic generalized epilepsies.
    • broad spectrum agents have variable efficacy for specific seizure types.
• Follow-up considerations:
  • The decision to treat a first unprovoked seizure with long-term antiseizure medications may be based on factors such as known neurological deficits, abnormalities detected by MRI or EEG, risk of injury, need of patient to drive, and social issues.
  • All patients with a first seizure should see a specialist with training and expertise in epilepsy within 4 weeks.
  • The highest risk of seizure recurrence is between 3 and 6 months following the initial seizure.
  • Patients may have significant psychological impairments due to the impact that seizures have on quality of life issues.