Status epilepticus (SE) is a common, life-threatening neurologic disorder that is essentially an acute, prolonged epileptic crisis. SE can represent an exacerbation of a preexisting seizure disorder, the initial manifestation of a seizure disorder, or an insult other than a seizure disorder. In patients with known epilepsy, the most common cause is a change in medication. Most seizures terminate spontaneously.

Essential update: Ketamine treatment in refractory status epilepticus

In a retrospective review of patients with status epilepticus refractory to typical antiepileptic drugs, ketamine was found to be effective and safe as an adjunctive treatment in all the patients.[1] Ketamine was the final antiepileptic drug used before seizure cessation in 7 of 11 patients; 1 additional antiepileptic drug was added after initiation of ketamine infusion in 4 patients.[1] Mean time from initiation of ketamine infusion to seizure cessation was 9.8 days; 7 patients achieved resolution within 1 week of initiation. Moreover, 6 of 7 patients who had required vasopressors during therapy were successfully weaned during ketamine treatment. No patients experienced acute adverse effects.[1] 2

Signs and symptoms

By clinical history, nonmotor simple partial status epilepticus involves subjective sensory disturbances, including the following:

Focal or unilateral paresthesias or numbness Focal visual changes, usually characterized by flashing lights

Focal visual obscuration or focal colorful hallucinations

Olfactory or gustatory hallucinations

Atypical rising abdominal sensations

Epilepsy partialis continua, or focal status epilepticus of the motor cortex, may occur in various contexts, with some authors subdividing it into type I (nonprogressive) and type II (progressive).

Type I epilepsy partialis continua features include the following:

Intermittent, semi-rhythmic, involuntary twitching involving a discrete subset of muscles Most commonly affects the face and ipsilateral distal hand musculature

Myoclonus of this variety may evolve into partial or generalized convulsion

Type II epilepsy partialis continua features include the following:

Usually linked with Rasmussen encephalitis Gradual loss of unilateral function, with parallel focal or unilateral hemispheric atrophy

Impaired intellectual skills to various degrees

Possible effect on language skills

Type I complex partial status epilepticus refers to recurrent, recognizable complex partial seizures without recovery between seizures. Type II represents continuous, ongoing complex partial seizure activity. The sequence of constellation of features in complex partial status epilepticus is as follows:

1. Serious medical, surgical, or neurologic illness2. A brief convulsive seizure

3. Protracted stupor with fluctuating neurologic findings, subtle nystagmus, or focal twitching

In addition, complex partial status epilepticus may have the following characteristics:

History of recurrent or prolonged simple partial seizures or may follow or precede a generalized convulsive seizure

Confused and variable responsiveness; fluctuating or bizarre behavior

Impaired memory of the event

Clinical automatisms (eg, repetitive lip-smacking, fumbling, swallowing movements)

Subtle nystagmus

See Clinical Presentation for more detail.

Diagnosis

Examination for status epilepticus includes the following:

Generalized convulsive status epilepticus: Typical rhythmic tonic-clonic activity, impaired consciousness; rarely, may present as persistent tonic seizure

Status epilepticus due to the use of illicit, or street, drugs: needle-track marks

Status epilepticus due to possible mass lesion or brain infection: Papilledema, lateralized neurologic features

Subtle or transformed status epilepticus: Any patient without improving level of consciousness within 20-30 minutes of cessation of generalized seizure activity

Associated injuries in patients with seizures: May include tongue lacerations (typically lateral), shoulder dislocations, head trauma, facial trauma

Classification

The Luders and Rona semiologic classification consists of 3 axes, as follows[2] :

The type of brain function predominantly compromised The body part involved

The evolution over time

The Treiman classification is as follows:

Generalized convulsive status epilepticus Subtle status epilepticus

Nonconvulsive status epilepticus (eg, absence, complex partial)

Simple partial status epilepticus

Testing

The workup for potential status epilepticus is similar to that for any self-limited seizure but is done more expeditiously to confirm the diagnosis and to abort or limit the seizures.

Stat laboratory studies that should be obtained include the following:

Glucose and electrolyte levels (including calcium, magnesium) Complete blood count

Renal and liver function tests

Toxicologic screening and anticonvulsant drug levels

Arterial blood gas results

Other tests that may be appropriate depending on the clinical setting include the following:

Electroencephalography: Criterion standard for diagnosing status epilepticus[3, 4] ; however, neurologic consultation is usually required

Blood cultures

Urinalysis and/or cerebrospinal fluid analysis

Imaging studies

Imaging modalities used to evaluate status epilepticus may include the following:

CT scanning and/or MRI of the brain Chest radiography

Procedures

If a central nervous system infection is suspected, consider performing a lumbar puncture (after neuroimaging to rule out potential cerebral herniation).

See Workup for more detail.

Management

Aggressive treatment is necessary for status epileptics. Clinicians should not wait for blood level results before administering a loading dose of phenytoin, regardless of whether the patient is already taking phenytoin.

Pharmacotherapy

Most patients with status epilepticus who are treated aggressively with a benzodiazepine, fosphenytoin, and/or phenobarbital experience complete cessation of their seizures. If status epilepticus does not stop, general anesthesia is indicated.

Medications used in the treatment of status epilepticus include the following:

Benzodiazepines (eg, lorazepam, diazepam, midazolam): First-line agents Anticonvulsant agents (eg, phenytoin, fosphenytoin)

Barbiturates (eg, phenobarbital, pentobarbital)

Anesthetics (eg, propofol)

Supportive therapy

Supportive care in patients with status epilepticus includes the following:

Maintenance of vital signs Airway, breathing, circulation (eg, hemodynamic/cardiac monitoring)

Respiratory support, with intubation and/or mechanical ventilation if necessary

Periodic neurologic assessments

Surgery

Surgical intervention for status epilepticus is a last resort and rarely performed.[5, 6, 7, 8] Operative procedures depend on the etiology of this condition and may consist of ablating a structural abnormality, hemispherectomy, subpial resection, or placement of a vagus nerve stimulator.