Approach
The clinical presentation of SE is highly variable. Most types are associated with a complete or partial alteration in consciousness, which limits history-taking to family members or friends. Pertinent medical history includes drug adherence and recent changes to medication, recent illnesses, history of alcoholism, and recent recreational drug use.[32] Knowledge of these potential precipitating factors may help direct emergency treatment of SE; the etiology should be treated as soon as possible.[2] Furthermore, because SE is considered an emergency in most cases, an ABCDE assessment and clinical examination should precede a full history-taking. A neurology consultation is highly recommended for all patients with SE.
Generalized convulsive SE
Patients with generalized SE are usually brought into the emergency department by ambulance. Characteristically, the examination reveals an unconscious patient with intermittent or continuous convulsions, initially with tonic and clonic phases, often followed by more subtle motor activity.[2] Motor activity may become asymmetric, asynchronous, or discontinuous. A prior history of epilepsy or SE may help the physician confirm the diagnosis, although many cases (up to 54% in one study) occur in the absence of a known diagnosis of epilepsy.[33]
Treatment is indicated urgently to prevent serious complications and death.[20][34] When the motor activity abates, electroencephalographic (EEG) monitoring will be needed to differentiate between persistent subtle SE and postictal confusion.[35]
Nonconvulsive SE
Patients with the generalized (absence) form of nonconvulsive SE usually present with confusion or clouded consciousness, with no apparent motor activity. Besides the change in behavior or affect, the remainder of the neurologic examination can be nonfocal. Because motor findings are limited or even absent, EEG monitoring to confirm the diagnosis is usually indicated.[35]
Patients with focal nonconvulsive SE typically present with altered consciousness (formerly complex partial).[2][34] They may also exhibit altered or strange activity, such as facial or limb automatisms, dystonic posturing, and restlessness.[20]
In the case of focal SE without impairment of consciousness (aura continua, with autonomic, sensory, visual, olfactory, gustatory, emotional/psychic/experiential, or auditory symptoms), the patient usually presents with continuous unilateral or focal clonic activity with clear sensorium (formerly simple partial SE).[7] The examination may also be normal in the case of sensory or autonomic seizures, as these are subjective feelings. In other rare cases, the patient may have isolated aphasia.[7] History of focal structural brain lesions may be suggestive of this diagnosis. In some cases, EEG may be helpful in confirming the diagnosis. Children with progressive neurologic and refractory seizures should have serial magnetic resonance imaging of the brain to assess for the typical atrophic changes of Rasmussen encephalitis.[17]
Focal SE without impairment of consciousness is rarely considered a medical emergency. However, this form of SE may occasionally be severely disabling. Brain imaging may reveal a structural lesion explaining the origin of these seizures.
Diagnostic tests
Generalized convulsive SE and nonconvulsive SE are neurologic emergencies requiring urgent management. None of the diagnostic tests must interfere with or delay treatment.[36] Vital signs should be checked, including oxygenation status, by pulse oximetry (with an arterial blood gas [ABG] if necessary), as well as serum glucose level.[36] An ECG should be obtained and blood sent to check liver function, renal function, electrolytes, calcium, phosphorus, magnesium, complete blood count, toxicology, and serum anticonvulsant medication levels.[37] Computed tomography of the head may be indicated when a structural lesion such as a stroke, abscess, or trauma is suspected. In the case of immunosuppression, or when signs of meningismus are present (fever, neck stiffness), a lumbar puncture is indicated.
The American Clinical Neurophysiology Society (ACNS) recommends continuous EEG (cEEG) to exclude possible nonconvulsive SE after clinical seizures.[35]
The ACNS recommends cEEG for a minimum of 24 hours in critically sick patients with:[35]
Persistent abnormal mental status following generalized convulsive SE or other clinically evident seizures. This includes patients without clear signs of improvement of alertness within 10 minutes, or any impairment of consciousness more than 30 minutes after cessation of motor activity, or other clinical signs of seizure activity.
Acute supratentorial brain injury with altered mental status.
Fluctuating mental status or unexplained alteration of mental status without known acute brain injury.
Routine EEG that shows periodic discharges (generalized, lateralized, or bilateral independent) or lateralized rhythmic delta activity. These EEG patterns are more often seen in patients who develop nonconvulsive seizures.
Requirement for pharmacologic paralysis (e.g., therapeutic hypothermia protocols, extracorporeal membrane oxygenation), and risk for seizure.
Clinical paroxysmal events suspected to be seizures, to determine if they are ictal or nonictal.
If resources do not permit cEEG monitoring, frequent serial EEGs should be obtained to guide therapy, and physicians may consider transferring the patient to a facility with cEEG capabilities.
Use of this content is subject to our disclaimer