As a PEM physician I must worry (and therefore rule out and treat) the true emergencies first. That is why I first check for what is emergent and what I can fix. Since my patient population varies greatly with regards to age I find it very important to know the epidemiology, in other words, what is the most common cause of X based on the patient’s age. Please consider contributing to PEM Rules at https://ko-fi.com/pemrules And check out www.pemrules.com  Copyright PEM Rules LLC