Dustin had a history of seizures that were always mild and only happened at night. He took his medication faithfully. But a couple of months ago he had a bad one.
The emergency room workup showed that his phosphorous was critically low. They replenished it intravenously and his level normalized and stayed up.
My reading when I saw him in followup suggested that hypophosphatemia is sometimes transient without explanation, but sometimes related to vitamin D deficiency.
I prescribed vitamin D, which is something I rarely do because I’m very skeptical of D supplementation. I describe D levels as a lab test looking for a disease. Here in northern Maine all mental health professionals tell her patients to take vitamin D for seasonal affective disorder with no scientific backup.
So Dustin got his prescription for vitamin D and his phosphorus level stayed OK for a while but next thing I knew he was in the emergency room again with a seizure and a low phosphorus. I added a vitamin D level to the serum already in the lab and it had not budged at all.
I knew Dustin smoked a lot of weed and the emergency room pointed out the same thing. I realized that I should have been more aggressive with my dosing of his vitamin D but I just had a funny feeling that maybe there was a connection between marijuana use and low phosphorus.
I asked my esteemed colleague, Dr. Google. He instantly brought an article to my attention about a probable connection between marijuana use and low phosphorus.
So I cranked up Dustin’s vitamin D dose and gave him a printout of the article. “You might want to cut back on your marijuana use”, I suggested.
I guess I’m hedging my bets here between the low D and the high THC, and I’m open to other possibilities. The big message here, for what my CEO called a “late career physician”, is (and I’ve said it before): May I never lose my curiosity. (Although in the post below, it seemed like CBD oil did something good – always ask, always wonder, always question…)
A Country Doctor Writes: 
I can’t tell you how much I agree with your maxim that curiosity is the antidote to burnout (although I am not quite convinced that it overpowers EMR fatigue!). Although recently semi-retired, I always told medical students and residents that I don’t think I have had a week when I have not seen something I have never seen before. If you just want to shoehorn every set of signs and symptoms into the diagnoses you already know, and blow off the ones you can’t figure out, primary care will be boring. If you are curious about them you will be amazed at how much remains for you to discover and learn. Even though individual rare diseases are rare, there are so many of them that overall they are common, and we miss them (almost) all the time. Just in my last few months I came across Acute Genital Ulcers (Lipschuetz Syndrome), Alpha-Gal, and late effects of ciguatera toxicity – and who knows what I missed!