Status Epilepticus Consensus Statement 2023

Status Epilepticus and Acute Seizure Management Consensus Statement 2023

The ACVIM Consensus statement about status epilepticus (SE) was published this past summer (2023) and I felt it was applicable to all of us faced with acute seizure management. They dove right in and addressed the need for a definition of a prolonged seizure as one occurring for longer than 5 minutes. The human equivalent of our International Veterinary Epilepsy Task Force (IVETF) is the International League Against Epilepsy (ILAE). The ILAE has recently also revised their definition of SE to any seizure longer than 5 minutes as well. Previously, SE was defined as anything between 5-30 minutes. Thirty minutes was the cut off because at that point, brain damage is common. The reason for adopting the 5 minute rule was to 1) minimize the risk of systemic and brain complications associated with continuous seizure activity reaching up to 30 minutes; 2) prevent worsening of the prognosis and drug resistance associated with increasing duration of uncontrolled seizure activity and 3) limit any potentially unfavorable outcomes and adverse effects associated with the prolonged administration of multiple therapeutic interventions. 

Status Epilepticus is divided into 4 stages:
1) Impending (occurs at 5-10 minutes of seizures) - there is neurotransmitter imbalance and ion channel opening/closing. Animals are likely to be responsive to first line anticonvulsant drugs (ACD) during stage 1. 
2) Established (occurs at 10-30 minutes)- Inhibitory neurotransmitters are reduced, the receptors for the inhibitory neurotransmitters are internalized and there is upregulation of NMDR and AMPAR. Some animals may still be responsive to first line ACD, but most will be responsive to second line ACD.
3) Refractory - (occurs > 30 minutes) - There is a sustained imbalance between inhibitory and excitatory neuropeptides with BBB drug transporter upregulation. Most pets will not be responsive to first or second line ACD, but should be responsive to third line ACD. 
4) (Super)refractory - (occurs > 24 hours) - There are gene expression alterations and animals are expected to be refractory to all ACDs. 

What were considered first line ACDs? IV benzodiazepine drugs were considered the most effective and safest for in-hospital use and intranasal benzodiazepines are the preferred treatment for out-of-hospital treatment. "Although both midazolam and diazepam are potent and safe for the management of SE in dogs and cats, midazolam may be considered a more potent or safer benzodiazepine drug than diazepam." There we go!

They provided a list of the steps to follow, based on the evidence reviewed, when treating SE. I have repeated it here, but encourage you to read the entire article if you treat SE regularly as there are loads of pearls of wisdom peppered throughout the paper.

Steps to follow for SE:

  • Give midazolam or diazepam IV. A benzodiazepine bolus is effective if the seizure stops < 5 minutes after administration and no relapse occurs <10 minutes

  • If seizure activity is controlled with a benzodiazepine drug but recurs 10-60 minutes later is considered recurrent SE

  • Recurrent SE, or those that don't respond to the first bolus of benzodiazepine, should get a second IV dose of benzodiazepine drug

  • If seizures persist after two bolus, administer a 3rd dose immediately followed by a CRI. Dogs = midazolam or diazepam CRI is acceptable; Cats = diazepam should be avoided. 

  • If seizures still persist, administer a 4th dose of benzodiazepine and administer a second line ACD

  • Second line ACD include levetiracetam IV, followed by phenobarbital IV and lastly fosphenytoin IV. Only administer the subsequent drug if the prior failed to stop the seizures. 


Note: Levetiracetam or phenobarbital IV can be started after step 2 above if long-term maintenance is desired for either medication. They do not need to be reserved for second line use only. 

I think that is enough for today. I'll go through some more data from the study in another TidBit Tuesday. I hope you enjoy the rest of this week, have a safe, relaxing holiday and look forward to working with you soon!