In the original format of an Admission History and Physical, the “History of Present Illness” spoke to the single problem for which the patient needed to be hospitalized. The “Past Medical History” described problems the patient might have had in the past, but by definition, were behind them. In the days when patients were admitted for a single acute illness, the distinction was clean.
As medicine became progressively more successful turning once-fatal conditions in to manageable chronic diseases, the distinction between “Past Medical History” and the patient’s current problems became fuzzy. When a patient with type 2 diabetes mellitus is admitted to the hospital with urosepsis (excuse me, sepsis of urinary origin), is the diabetes part of the “history of present illness” or the “past medical history”? The patient isn’t being admitted because of their diabetes, and yet, it’s wrong to say it’s part of their past medical history because its an ongoing, usually lifelong problem requiring active management. In practice chronic medical illnesses started to show up in both places – the HPI would begin “Ms X is a 75 year-old female with type 2 diabetes admitted for urosepsis”, but the diabetes would appear again in the PMHx. For patients with multiple chronic medical illnesses, the HPI one-liner got packed with a comma-separated list of ongoing conditions, which then line up duplicatively in the PMHx, there joined by medical problems truly in the past.
In an electronic health record this fuzziness becomes obvious because a problem-based EHR (Epic for example) forces the physician to put their nickel down. Is the Past Medical History really in the past? The actively managed Problem List is integrated in to documentation, order writing, signout, and many other clinical functions. The diabetes belongs on the “Problem List”, not the Past Medical History, because it is an ongoing, not past, condition.
I just finished discussing this at UCLA as the Medicine housestaff are building up their inpatients’ problem lists for the first time. At UCSF we’ve tried to move the culture towards using the Problem List for all the patient’s active medical issues, including chronic issues, and reserving the Past Medical History for items actually in past. I remember pitching this for the first time to our Medicine residency program leadership, who looked at me like I had two heads. (in the most friendly and collegial way) Today’s patient is likely to have more present problems than just one. It’s a culture change, but it’s more accurate, more concise, and consistent with the original distinction between the HPI problem(s) in the present and past medical problems in the actual past.