Experienced clinicians begin the process of making a diagnosis upon first laying eyes on a patient, and probability is one of the main tools they use in this process. A glimpse “behind the scenes” from the point of view of a diagnosing physician might help to explain an otherwise mysterious process.
The diagnostic process can begin even before laying eyes on the patient. As an exercise (and to prove a point) I ask medical students who are with me in the office to diagnose the patient we haven’t seen yet who is still in the waiting room. Of course, they look at me like I’m crazy. But I tell them that we already know a lot about the patient and can make some educated guesses. For example, we might already know that the patient is a 34-year-old woman referred by a family doctor because of headaches.
So what have other women in their thirties referred to me for headaches ended up having as their diagnosis? In my neurology practice, as well as in those of most other headache specialists, about a third (33%) have migraine, another third have medication-overuse headaches (in which the treatment has become the problem instead of its solution), and...