Myoclonus From Sedation

[Catticus11]

I had a patient on Propofol and Fentanyl who began to shake and originally I thought he was seizing, but my charge nurse stopped and said it appeared to be more like myoclonus which can happen from sedation.

Can someone help me find more literature on this?

[Cvepo]

It was most likely the propofol. Try searching for propofol induced myoclonic movements or something. Propofol is an excellent sedation drug but it has some nasty side effects and should never be used for a long time. I've had 2 patients develop propofol infusion syndrome in my first year of ICU nursing alone!

[Catticus11]

Thank you so much for the response. Would I treat seizures vs. diprivan induced myoclonus the same?

[NewHam CRNA]

A number of sedatives/anesthetics cause myoclonus that appear similar to tonic-clonic seizures but are distinct from them on EEG:

Propofol, etomidate, barbiturates (not used in US).

It tends to happen with small doses of these drugs, but can be seen with large bolus doses such as during induction of anesthesia. The exact mechanism of this excitation is unclear. It is likely secondary to subcortical glycine antagonism. But do not let it scare you as these drugs are anti-epileptic. The myoclonus is usually self-limiting and does not require treatment. By the time you could even go fetch a benzo the myoclonus will be gone as these drugs take their effect at the GABA receptor.

That said, if a patient has been on a propofol infusion for awhile and begins having myoclonus, that is something to mention to your MD/NP/PA. Though, absent an intracranial process, drug toxicity (like local anesthetics), or resistant epilepsy is very unusual to have a seizure on propofol.

Fentanyl can in rare causes cause muscle rigidity, but this usually manifests as muscle stiffness or difficulty ventilating (high peak pressures), and usually doesn't look like myoclonus.

[MunoRN, RN]

Was this a post-arrest patient?

[Catticus11]

Was this a post-arrest patient?

No, he originally came in c/o dizziness, so he went to a cardiac telemetry unit where he fell and hit his head. He was transferred to CCU after that, where he began to become Apneic and developed a respiratory acidosis per ABG, so he was intubated. There was a question of ETOH use prior.

[offlabel]

A number of sedatives/anesthetics cause myoclonus that appear similar to tonic-clonic seizures but are distinct from them on EEG:

Propofol, etomidate, barbiturates (not used in US).

Brevital is used in the US.