In a random medical discussion with a surgeon friend over a bottle of Oregon Pinot as we Portlandiputians are wont to do, she brought up a condition she had come across in surgery that piqued my interest.
Despite never having heard of it (being relatively new to this field this happens a lot) it has it’s own association!
http://www.mhaus.org/ – The Malignant Hyperthermia Association of the United States.
We’ll just ignore that this is an American institution and yet the acronym they chose, “haus”, is German. I’m certain to lose sleep over that inconsistency later, but for now let’s just merrily roll along. Yesterday is done… see the pretty country side. <–You might find I quote Sondheim a lot. I encourage you to do your research in that specific field as I do mine in this one. 🙂
So… Malignant Hyperthermia, ‘MH’ from here on in because typing, is a medical crisis that is triggered by commonly used surgical anesthetics and the particular neuromuscular blocking paralytic succinylcholine. An MH crisis comes with the rapid onset of increased metabolism, muscle rigidity, tachypnea, and body temperatures that may exceed 110F.
Yes you read that right: 110F. Or 43.3C if you’re German and live in a ‘haus’. I will never let that go.
This condition is obviously, extremely deadly.
It’s also genetic and passed through a dominant gene meaning the children of an MH patient are 50% likely to also have it.
Physiologically, this gene mutation results in an abnormal protein in the muscle cells that, when exposed to certain agents, commonly anesthetics for surgery, causes a rapid deploy of calcium from the sarcoplastic reticulum, triggering hypermetabolism that depletes the muscles of their ATP leading to muscle death leading to a a potassium storm (hyperkalemia) which causes arrhythmias and on to cardiac arrest and multiorgan failure / injury.
It may be hot, but it ain’t pretty.
The drugs that trigger this are the general anesthetics in the “ane” class, Halothane, Isoflurane, Enflurane, etc. But the most serious culprit is the depolarizing muscle relaxant succinylcholine.
List of safe and unsafe drugs for MH patients can be found here. You know, just in case you were about to perform surgery and needed my guidance.
MH has one antidote: Dantroline. So again, if you’re about to perform surgery you might wanna keep it handy. In fact, in most hospitals, having Dantroline at hand for surgery is… wait for it… wait for it..
Because being hot is not always a good thing.