The issue in this case is determining which of the probable causes is the actual cause. This one liner from the resident needs to be followed very quickly with a brief summary so that I can get back to sleep safe in the understanding that all has been thought of and assessed. At this early point, I am thinking about a finite list - as my Professor of Surgery said "Never less than 2, never more than 4!" which includes:
- ordinary DVT
- PRCA in pelvic LN causing lymphoedema of the leg
- expansile metastasis in a bone
So I am now going to be listening for differentiating factors between these three conditions. In this regard, I would be expecting some historical features that tell me about
- accompanying pain
- calf & groin V none V well localised to part of the leg
- with walking V without walking
- differentiated from pain of a swollen leg (a pressure pain)
- signs of inflammation (calf V none V none),
- deformity of the leg
- little oedema V very swollen leg V localised leg deformity
In terms of examination, I would expect a clear definition of physical findings in the scrotum, groin, upper and lower leg. I would NOT expect a CT to have been done without a discussion with a senior doctor, where the diagnostic possibilities are detailed. In fact an ultrasound of the leg would probably be my first suggestion with respect to ED management. That is the condition that has to be ruled out - always keep an eye on this - which of these diagnoses is going to kill the patient in front of me? And which of these diagnoses is going to maim the patient in front of me?
And my other expected investigation would be a X-ray of the leg. Another of my old professors used to say "high content, low probability; low content, high probability", meaning that you should start with the general test before moving to nail the diagnosis with the definitive test. Another one, a pathologist, used to say "low power, high power thinking; high power, low power thinking" which is the pathologists equivalent phrase. The general tests in this case are directed to the bone and the soft tissues. One will detect bone deposits, fractures and expansion, the other will detect DVT and pelvic lymph nodes (at a pinch). You see, if the leg X-ray is clear, then bone metastasis causes are ruled out, and you didn't need to use up a CT slot!
If DVT is absent, the other conditions are not life threatening and can be dealt with next week. If there is no clearly delineated clinical cause for the swelling so that DVT is not excluded, then commencement of anticoagulants is expected.
After admission and depending on what is found, investigations should be undertaken should look to confirm the cause. A CT scan is quite useful as it will delineate the extent of the cancer in nodes and the condition of bone, of course it will be unlikely to show any venous pathology.