Status epilepticus is one of the few neurologic emergencies.  Many protocols for persistent status involve dosing with a benzodiazepine, then another benzo, then an antiepileptic medication, and finally, continuous sedation with intubation.  The Sinai protocol is found here.

But what if the seizing doesn’t stop?  How long can we wait for these medications to work before there is permanent damage?

The traditional approach targeted termination at under 60 minutes; however, complications like neuronal loss and cerebral metabolic decompensation can occur within 30 minutes.  An RCT showed that pre-hospitalization benzodiazepine administration for seizures reduced mortality from 15 to 6%, proving that early intervention saves lives.

It has been shown that if a benzodiazepine did not break the seizure with the first administration, it is unlikely to break it with the second one.  Additionally, antiepileptics are often not readily available, can take time to infuse and metabolize (fosphenytoin), and may not work with the first administration.  This can mean status > 30 minutes.

For this reason, literature is now pointing toward rapid sequence termination as more beneficial for the patient.  Under this approach, a benzodiazepine is first-line approach, with second-line being intubation and general anesthesia (with versed, propofol, or ketamine).  Then, an antiepileptic can be administered.  For AEDs, fosphenytoin and phenytoin are most studied, but given their potential for CV toxicity and the equivalent efficacy of alternatives, clinicians are moving toward using VPA or keppra instead.

Finally, for seizures/status epilepticus that is undifferentiated and does not respond to benzodiazepines, consider a toxic etiology.  Specifically, INH toxicity requires administration of pyridoxine (5g IV for adults, 70mg/kg for children) for seizure cessation.  Other toxins like TCAs, HF, organophosphates, ASA and theophylline should have some response to benzos, but require other targeted therapies for complete treatment. 

Sources:

http://www.pulmcrit.org/2014/06/rapid-sequence-termination-rst-of.html

http://emcrit.org/?s=status

Alldredge 2001

Trinka 2014

Wasterlain CG, Treiman DM, eds. Status Epilepticus: mechanisms and management. Boston: MIT Press; 2006.