During MD days, I had seen some patients from Immunology / Rheumatology whose case sheets read, “undifferentiated arthritis”. It was an interesting term, which I learnt means an arthritis which can’t be classified as anything more specific. I wondered if there is a difference between undifferentiated and idiopathic.
In medical terms, idiopathic means “We don’t know the cause”. It can also be thought of as, “We don’t know the cause …YET”. The last 3 letters are important , because it tells whether to proceed further with more and more esoteric and expensive diagnostic tests. Idiopathic by common understanding, has a ring of finality to it. It seems to say, “we are done and we didn’t find the cause”
On the other hand, “undifferentiated” is much more open ended. It focuses on the “YET” part. It means that the diagnosis is a work in progress.
At first glance, this might seem like some academic hair-splitting and manufactured debate over semantics. In reality though, diagnosis is an extremely important part of medicine.
It’s a label. A label that reads “ In progress” is more useful than one that reads “Done, but none”. We care about diagnostic labels, because they stick. Sometimes, forever.
