Status Epilepticus

This is a lead-up blog for our C & C next week where we will discuss SE = Status Epilepticus.

Midazolam and valproate administrations for the seizure management have been recently added to the paramedic ATP. RSI consideration has also been highlighted for the management of SE. Here is some cool FOAMed to help us understand the rationale for the current CPG as well as extended paramedic ATP.

What is status epilepticus (SE) ? – Epilepsy Foundation?

SE is said to occur when a seizure lasts too long or when seizures occur close together and the person doesn’t recover between seizures. Just like there are different types of seizures, there are also different types of status epilepticus.

Over the last several decades, the length of seizure that is considered as status epilepticus has shortened. Years ago, a seizure needed to last longer than 20 minutes to be considered status epilepticus. In the last few years, it is now defined as any seizure greater than 5 minutes. This makes sense because most seizures do not last longer than 2 minutes. The longer a seizure lasts, the less likely it will stop on its own without medication. Very long seizures (i.e. statue epilepticus) are dangerous and even increase the chance of death. It is important that these long seizures are identified early so that they can be treated early.

St John defines SE as;

“A single seizure lasts longer than 30 minutes despite treatment or
Multiple seizures are occurring and the patient remains unconscious between them”

I questioned our Clinical Excellence team about the “30 minutes” and their response was;

“Do not fixate on the definition, it tends to wander a little depending on the source. In terms of the treatment – like all conditions seizures are a continuum.
–        For patients who experience generalised seizures but remain relatively well perfused and relatively well oxygenated (usually these are the patients who have recurrent not continuous seizures) persisting with the full range of anticonvulsants is reasonable.
–        For patients who experience generalized seizures whom are clearly poor perfused and or hypoxic and the seizures are continuous, having a lower threshold for RSI is acceptable (noting that RSI will stop the symptoms not the seizure and this needs to be taken into account as part of your post intubation sedation regime).”

! Please note this answer was aimed at ICP practice.

 

Starship Clinical Guidelines for SE confirms the various definition of SE.

 

The first FOAMed I like and would like to recommend is “PulmCrit- Resuscitationist’s guide to status epilepticus”
In this blog, Dr Farcas states; “best outcomes rely upon rapid seizure control.  The longer the seizure continues, the more refractory it becomes to therapy.  The duration of status epilepticus which may cause permanent brain damage is unknown, with experts currently suggesting thirty minutes (Zaccara 2017).  Aside from the brain, persistent status epilepticus may cause aspiration, hyperkalemia, rhabdomyolysis, hyperthermia, myocardial infarction, and arrhythmia.”

 

Checking EMCrit Podcast 155 – Status Epilepticus with Tom Bleck and PulmCrit- Resuscitationist’s guide to status epilepticus should also give you the following summary:

• Status should be considered refractory after the failure of the first agent that should have worked
• The longer you seize, the tougher it will be to break
• Seizure at 5 minutes, there is an 80% or greater chance that patient will continue seizing if not treated.
• Permanent brain damage may occur with SE > 30 minutes

The first point leads to Dr Bleck also recommending the move to general anaesthesia after the failure of the first agent. While our current CPG does not recommend RSI post midazolam, above response from our Clinical Excellence team should explain the rationale for our current CPG well.

Here is an article written by a NZ doctor “Algorithm for the treatment of status epilepticus: a New Zealand perspective – Iniesta-2017-Internal_Medicine_Journal.

The article focuses on the algorithm provided by the authors to health practitioners for the treatment of status epilepticus(SE). Topics discussed include information on neuropsychiatric manifestations associated with antiepileptic drug (AED); recommendation for avoiding levetirazetam in mental health problems; and need for retrospective audit in order to standardise the treatment of SE.

 

In summary, I’ve taken home the following points from various FOAMeds (so far) for my own paramedic practice;

1. Seizure > 5 mins should be treated
2. Early, first benzo (midazolam for us) has the best chance of stopping the seizure. – This is the reason why the first dose of midazolam has been increased.
3. Do not delay IM midazolam if IV access is difficult.
4. Failing the first good dose of midazolam has a high chance of prolonged SE. – This is the reason why we have the upper limit for the midazolam administration (15 mg for IV, and repeat once only for IM) (* Repeat once only for either IV/IM – Thanks Jason W for pointing out the mistake!), while we have none for the agitated delirium patients.
5. Convulsive SE > 30 mins may be linked to the permanent brain damage.

The implication for the increased midazolam dose is also clearly stated in our CPG. Be prepared to do good basic airway manoeuvers, and consider RSI back up early if the first midazolam do not work and airway or ventilatory compromise is evident.

St John CPG states:

• Backup from an ICP must be requested when more than one dose of midazolam is administered or valproate is to be administered.
• Request backup for RSI in all patient with status epilepticus as this can cause brain injury via combination of hypoxia and hyperthermia.

* Valproate is given as an infusion over 10~15 minutes, and RSI officer may choose to intubate prior to commencing valproate infusion if airway or ventilatory failure is imminent.

OK, this is getting too long and the best thing to do is for me to shut up and let you hear from the expert. I really enjoyed the following podcast by Dr Bleck on SMACC.

CONTROVERSIES IN THE ACUTE MANAGEMENT OF STATUS EPILEPTICUS

Summary by: Oli Flower

Tom Bleck has been in the top echelons of neurocritical care for decades. As a highly active member of the CCM-L internet group, he was pioneering internet based crit care discussions before Twitter was ever conceived. Considered by many to be the leading world expert on status epilepticus, he brings insights from research and extensive experience you will hear from no one else. A rare treat.

Read the “RAMPART trial” mentioned in the podcast.

Also, “Intramuscular versus Intravenous Therapy for Prehospital Status Epilepticus”

And this year, “Pre-hospital midazolam for benzodiazepine-treated seizures before and after the Rapid Anticonvulsant Medication Prior to Arrival Trial: A national observational cohort study”

Please share your thoughts, knowledge, and other great FOAMeds that you know for this subject!

Cheers,

T

References;

https://www.smacc.net.au/2016/07/controversies-acute-management-status-epilepticus/

Epilepsy Foundation http://www.epilepsy.com/learn/impact/seizure-emergencies/status-epilepticus

Silbergleit, R., Lowenstein, D., Durkalski, V., & the Neurological Emergency Treatment Trials (NETT) Investigators, R. (2011). RAMPART (Rapid Anticonvulsant Medication Prior to Arrival Trial): A double-blind randomized clinical trial of the efficacy of IM midazolam versus IV lorazepam in the pre-hospital treatment of status epilepticus by paramedics. Epilepsia, 52(Suppl 8), 45–47. http://doi.org/10.1111/j.1528-1167.2011.03235.x

Silbergleit, R., Lowenstein, D., Durkalski, V., & Conwit, R. (2013). Lessons from the RAMPART study – and which is the best route of administration of benzodiazepines in status epilepticus. Epilepsia, 54(0 6), 74–77. http://doi.org/10.1111/epi.12284

Shtull-Leber, E., Silbergleit, R., & Meurer, W. J. (2017). Pre-hospital midazolam for benzodiazepine-treated seizures before and after the Rapid Anticonvulsant Medication Prior to Arrival Trial: A national observational cohort study. PLoS ONE, 12(3), e0173539. http://doi.org/10.1371/journal.pone.0173539