To that end, Lisa and I attended a pair of lectures about swollen brains: how to prevent, evaluate and treat. I know, I know, you’re asking me if we’ve found some new exotic treatment for my swollen ego. Sorry, the magic hubris bullet will be covered in another blog post. Instead, we got an interesting take from the famed Dr. Peter Hackett and our Aspen ER doc Scott Gallagher, also an expert on altitude and backcountry related medical issues.
While I found Hackett’s lecture amusing and educational, where the gist of the session resided (for me) was in Gallagher’s talk comparing hyponatremia to the cerebral edema caused by poor adaptation to high altitudes. The altitude version is known as HACE, while the brain swelling brought on by exercises and over-hydration is known as EAH, exercise-associated hyponatremia.
Hyponatremia is an imbalance of the body’s normal blood sodium levels. Minor occurrences can cause symptoms such as dizziness, while more extreme cases lead to death due to the brain swelling too large for the skull cavity and herniating through the opening at the bottom of the skull.
“Sub-acute” hyponatremia is somewhat common with the elderly, and during hospitalization for anyone. If the sodium fluctuations happen slowly it’s not usually lethal (though still at concern.) On the other hand, slugging down too much water can bring acute hyponatremia in mere hours, especially if you’re exercising (due to physical effort messing with a hormone that keeps sodium levels balanced.) Left untreated, or improperly treated, the condition kills. More, in my opinion, since moderate hyponatremia can cause dizziness and disorientation, un-diagnosed instances have probably resulted in quite a few accidents over the years.
For mountaineers, the problematic part of this is the old song: “You’ve got to stay hydrated, more hydration is the solution to altitude problems. Drink water. Keep drinking.” Turns out this is wrong. So wrong. “Drink when you’re thirsty, don’t over-hydrate” is now the consensus in sports medicine. That includes altitude. In fact, Hackett said that studies show over-hydration can lead to exacerbated altitude illness symptoms!
IMPORTANT: Electrolyte sports drinks will NOT prevent hyponatremia. None have the necessary (or desirable for normal use) sodium concentration. Again, drinking only when you’re thirsty, and not over-hydrating are the key factors.
And how shall us first-aiders tell the difference between altitude induced brain swelling and that of hyponatremia? Doing so is nearly impossible without specialized equipment. Testing blood for sodium levels is the key, but you’ve can’t do that without a portable blood analyzer such as the i-Stat — bulky, costing anywhere from $300 to $10,000. The takehome from both Glagher and Hackett was that patient history is key. If the subject has ascended quickly to the type of altitudes that induce illness, and has not been pounding water, that’s one thing. If altitude isn’t as big a factor, but you find out the person has spent a day in heavy exercise while drinking liter after liter after liter of water due to the discredited myths of athletics, consider EAH.
Either condition is of course serious. According to Hackett, if any change in cognition is present, immediate evacuation is key. With the caveat that common (and wrong) procedure for emergency med techs is to dump IV “normal” saline solution, but that doing so can kill a hyponatremia victim (has probably happened more than once) and doesn’t help someone with HACE. In the case of hyponatremia, the field treatment can be simply waiting for the body to excrete excess water, or perhaps an oral high-sodium solution such as a couple of bullion cubes dissolved in a small amount of water. If the equipment and materials are available, and blood sodium imbalance has been verified, treatment may include injecting high sodium concentration saline, or injecting the same sodium bicarbonate “amp” used by EMTs and doctors to treat cardiac arrest.
A few other things: In terms of social contract, it’s a good idea for groups involved in extreme mountain sports to monitor each other’s actions, such as hydration, calories, and so forth. If someone has a medical problem, patient history is key and sometimes the victim is too out of it to relate any meaningful information; companions can fill in the blanks. In terms of hyponatremia specifically, I’m told that most ambulance crews as well as medical helicopter services carry the blood analysis device. If hyponatremia is suspected, it’s not a bad idea to remind the EMTs to use their blood analyzer and pay attention to the sodium level number, as well as hesitating with the customary saline dump since starting a possibly contraindicated IV is nearly a reflex procedure for these guys. Give normal saline to a hyponatremia patient, you can kill them.
Web MD summary: https://www.webmd.com/a-to-z-guides/what-is-hyponatremia#1
And more here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5334560/
Interesting reading from Hackett: http://www.altitudemedicine.org/myths-about-altitude/