TB Course, Days 2 and 3

I realized this morning that I forgot to write about my day at the TB course yesterday. Oops. So today's entry will serve for both days. First of all, here's a picture of National Jewish Hospital back when it opened as a TB sanitarium in 1899:

Yesterday was a mix of helpful and not helpful information, which mostly means things I will need to know as a preventive medicine physician and things I don't need to know. How to screen people for latent TB is something that I need to know, because that's something that preventive medicine physicians do. Here's the reason why:

 

What this says is that if you have 100 people who are exposed to TB, 70 will be fine and 30 will become infected, which is known as latent TB infection. Since TB is such a slow-growing bacteria, for 27 of those, the infection will always be latent and they will never have active TB. For the remaining 3, half will have disease within two years, and the other half will have disease later in life (okay, bad example, since you can't have half a person, but you get the idea). The point of treating people with latent TB is to reduce their risk of having active disease in their lifetime from roughly 10% to less than 1%.

And this is how you screen someone for latent TB. When you have a person at high risk, such as someone born outside of the US or someone who has been around someone with active TB, you do either a TB skin test, which is also known as a PPD; or a blood test (IGRA, or immunoglobulin release assay). If that comes back positive, you do a chest x-ray to look for active TB. If the chest x-ray is abnormal, you probably end up treating for active TB, but if it's normal, they're said to have latent TB. And again, the reason why we treat people with latent TB is to reduce their risk of progression from 10% in their lifetime to less than 1%.

That was a good deal of yesterday and a bit of today. Today we also did a workshop for TB outbreak investigations, which was interesting, because there's a change I'll be in charge of one of those someday. It was kinda a good feeling that I got during this workshop, because I felt like I had a better handle on the situation than most people in my group, which makes me think that if I have to do that someday, that maybe I won't mess it up too bad.

Here's a parting thought for tonight, from the CDC doctor who was sent to Colorado to close their sanitariums and ended up staying for the rest of his life: