Is there anything magnesium can’t do?

I’ve often extolled the virtues of magnesium to my residents as well as on twitter. It’s a sign of a well seasoned emergency physician to take any medical problem, and say “a little magnesium couldn’t hurt.”

In this instance, a group of physicians in Bhutan had a patient with classic signs of tetanus and an absence of tetanus vaccination. He was given typical antitetanus serum, antibiotics, benzodiazepines, and opiate analgesics. The spasms continued through high doses of benzos (80mg in 24 hours), and on day 14 they decided to start magnesium sulfate for spasms. After 3 days of treatment, it became the only medication the patient was taking. He ended up getting it for 20 days, and did reasonably well as far as one can tell reading the case report.

But what made them try it? Only 2 other people at that hospital had ever been treated for tetanus with magnesium, and both of them died. This is compounded with that hospital’s lack of laboratory testing for serum magnesium level. Still, they did it, and by only following vital signs, sedation level, and deep tendon reflexes.

What may be surprising to many is that prior to this case report, a double blinded RCT of magnesium for the treatment of tetanus was performed on 195 patients. Thus, the authors weren’t completely off their rocker for attempting this treatment, novel as it may be to most.

Of course, the mechanism behind why this works is unclear. And there isn’t a clear indication as to why this is any better a treatment than typical neuromuscular blockade and sedation. Certainly, the toxicity of magnesium at high levels is well-known, I only consider this as one of those last-ditch efforts when standard treatment isn’t available or isn’t working. Even then, I would still prefer having lab testing to help guide treatment.

Wangmo KP, Teng M, Henker R, Kinnear S, Tshering J, Wang NE. Survival of a patient with tetanus in Bhutan using a magnesium infusion managed only by clinical signs. Wilderness Environ Med. 2014 Jun;25(2):194-7 [PMID 24792133]