renal handling of water

If you were on a tea & toast diet, how much water would you need to drink before you develop hyponatremia? I haven’t seen anyone work out the numbers before so here are my calculations. And the key to understanding hyponatremia is the renal handling of water. Take-home points #1: water follows solutes ⟶ need solutesRead more

acute acidemia physiology

As alluded to in the first post, don’t be fooled by a “normal” potassium in the setting of DKA because osmotic diuresis and H+/K+ exchange means that total body potassium is actually LOW. You all know this, but don’t forget to check the potassium before starting insulin. But what about the acidemia? How does that affect physiology? (reminder:Read more

renal handling of potassium

the first symptom of hyperkalemia is death Earlier post covered temporizing measures to counter hyperkalemia — namely, intracellular shift, increasing cardiac myocyte threshold potential. Give furosemide if the patient still urinates and consider dialysis, but then ask yourself: how did the patient get hyper K in the first place? Often, it’s b/c of missed HD. But don’tRead more

bicarbonate revisited

Previous post reviewed the safety of balanced crystalloids in hyper K. But what was up with serum bicarbonate decreasing with saline administration? This post introduces a new way of looking at the anion gap to possibly answer this phenomenon. This is the way we normally think of the anion gap (composed of anions like phosphate, albumin,Read more

hyperkalemia and balanced crystalloids

Is it safe to give LR or plasmalyte to a hyperkalemic patient (these balanced crystalloids have 4-5 mEq/L K as opposed to 0 mEq/L K in normal saline)? Postponing the discussion of renal handling of potassium to review the physiology of fluid resuscitation in the setting of hyper K (per request by Dr Hickey). This has been debunkedRead more

hyperkalemia physiology

You’ll likely encounter hyperkalemia on your next Resus / Cardiac shift, and you’ll instinctively treat it. But take a moment to review the fascinating physiology behind the “cocktail”! First, consider how K+ is buffered by cells:How do our treatments shift K+ intracellularly? … Key: Na-K-ATPase! 3Na+ out, 2K+ IN! And stimulated by the β2 and insulinRead more

Slow down your tachycardia (but not really)

You’re sitting in resus bemoaning the departure of your most beloved attending when suddenly a patient wheels in without warning. The patient looks relatively stable but the triage RN tells you her heart rate was in the 150s — no time for a full set of vitals or an EKG. You adeptly obtain these; theRead more

Otitis externa: use the ear wick!

Acute otitis externa (AOE) is a common complaint seen in pediatric as well as adult emergency departments. AOE is typically not accompanied by acute otitis media, although concurrent cases are possible. Also called “swimmer’s ear” due to the increased likelihood of developing after prolonged submersion in water, AOE can be caused by trauma, foreign bodiesRead more

Reach for the COWS

Your patient in intake is miserable. Doubled over, complaining of pain everywhere, sweating, ill-appearing but not unstable. He tells you that the last time he used heroin was two nights ago, and he is asking for help. How do you treat this patient? And how do you determine what medication would be appropriate? There areRead more

Tis the season, summer edition

As the late spring rains have begun to fade and the temperature rises mercilessly into the 80s and beyond, summer is finally upon us. And with summer comes a host of diseases for the emergency physician to consider. Heat stroke, mosquito- and tick-borne illnesses, chicken pox, an expanding measles outbreak…and a less threatening cause ofRead more