Whenever I encounter a hospital inpatient with an acute seizure, I make sure that I have IV lorazepam available. Most seizures stop after about 2 minutes. In reality this means that by the time the lorazepam has been brought to the bedside, the seizure is usually over.
When the seizure is over, I assist the team in identifying and treating the underlying cause of the seizure. Common reasons for an adult inpatient to experience a seizure include:
1. Intracerebral mass or bleed
2. CNS infection
3. Cerebral hypoxia
4. Drug overdose (such as tricyclic antidepressants)
5. Drug withdrawal (such as anticonvulsants, alcohol, or benzodiazepines)
6. Metabolic disturbance (low glucose or sodium)
If the seizure lasts more than 5 minutes, the patient is now considered to be in status epilepticus.
Status epilepticus is a neurologic emergency and can result in respiratory failure, cardiovascular collapse, and neurologic damage if it is not terminated.
Rapid treatment is essential for a good patient outcome.
Guidelines for the treatment of status epilepticus published in 2012 are available from the Neurocritical Care Society.
Treatment should begin immediately with a benzodiazepine. Use lorazepam 0.1 mg/kg IV or midazolam 0.2 mg/kg IM.
Avoid giving midazolam IV because this is more likely to cause respiratory arrest and force endotracheal intubation upon a patient who might not have required it.
Immediately after an appropriate dose of benzodiazepine is given, obtain medications necessary to support the patient if they develop respiratory failure or hypotension. This involves preparing medications for endotracheal intubation (see episode 15) and vasopressor therapy (see episode 5).
Whether or not seizure activity has stopped after you have obtained intubation and vasopressor medications, an anti-epileptic drug will be needed. A 2014 update (available free here) recommends levetiracetam (30 mg/kg IV), valproic acid (30 mg/kg IV), or phenytoin (20 mg/kg IV).
Refractory status epilepticus
Refractory status epilepticus is treated with general anesthesia and mechanical ventilation.
When status epilepticus is considered refractory is up for debate:
The 2012 guidelines state status epilepticus that persists after benzodiazepines and an anti-epileptic drug is considered refractory.
The trouble with the guidelines is they assume that an anti-epileptic drug is immediately available at the bedside to administer after initial benzodiazepines are given. In reality, ordering, preparing, dispensing and administering an IV anti-epileptic drug will take 20 minutes or more even in the most ideal circumstances.
In practice using the approach in the guidelines – waiting until an anti-epileptic drug fails to move to general anesthesia – may result in status epilepticus persisting for 60 minutes or more. The alternative definition of refractory status epilepticus serves to accelerate the time to general anesthesia and termination of status epilepticus. This is thought to be beneficial since the risk of serious neurologic damage increases greatly if seizure activity persists longer than 30 minutes.
Unfortunately there is no study either published or underway that examines whether moving toward general anesthesia faster results in better outcomes.
General anesthesia regimens for terminating refractory status epilepticus
There are 3 options I would consider for inducing anesthesia to terminate refractory status epilepticus:
Give 0.2 mg/kg IV followed by an infusion of at least 0.2 mg/kg/hr, titrating up to 2 mg/kg/hr. Watch out for tachyphylaxis which may necessitate dose increases.
Give 2 mg/kg IV followed by an infusion of 50 mcg/kg/hr. Watch out for hypotension and give a vasopressor to counteract this.
Give 3 mg/kg IV followed by an infusion of at least 1 mg/kg/hr titrating up to 10 mg/kg/hr.
For the pharmacist responding to an inpatient with status epilepticus:
1. Obtain the right amount of benzodiazepines fast.
2. Prepare to assist with supportive care.
3. Keep an eye on the clock with the goal of terminating seizure activity within 30 minutes.
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.