Here is a case study of a man with back/leg pain that I thought was radicular but ended up being a bit of back pain + peripheral artery disease.
He arrived with 6/52 h/o low back pain with leg pain. He felt the leg pain started in the calf and crept up through his hip to his low back. His aggs were walking 150 yards and bending and lifting. He had no PMH or FH of CVD.
He had had ‘sciatica’ before. He had a diminished R ankle jerk and no other hard neuro. SLR was +ve for his calf pain. In my “provisional diagnosis” box I wrote “low back pain with radicular pain / ?vascular”.
I asked him to do some basic physio exercises. He came back and his back pain and hip pain had resolved, but he said the exercises didn’t affect his leg pain either way.
Now that the back pain was gone, he had a really clear pattern of it being agg’d *only* by walking and relieved in under a minute when he stopped walking.
I asked my senior @physiotommid to look at him. He took the pt’s pulses (I do it but I’m crap) and was pretty sure they were absent on R side. He also got him doing heel raises which brought on his pain slowly as his exertion increased.
We referred him to his GP asking for an ankle-brachial pressure index test. Came back today positive and he is being referred on down that pathway.
So this is a case of peripheral arterial disease masquerading (to my novice’s eye) as radicular pain. You can see how the back pain with somatic referred pain (And a ?false +ve SLR…) complicated things. This BMJ infographic shows how PAD can easily seem like MSK pathology. 
The authors of this article give three more case studies of vascular claudication being treated as radiculopathy: amjorthopedics.com/article/dont-f…
So how can we be more confident in ruling out vascular causes of leg pain? Start with screening for risk factors. I did this but forgot to ask about smoking! (I know…). Turns out this pt had smoked since his teens.
This table shows the differences between vascular claudication, caused by peripheral artery disease; and neurogenic claudication, caused by multi-level spinal stenosis. ncbi.nlm.nih.gov/pubmed/24758955
According to this paper there are some pretty decent specificity stats for the subjective assessment alone to differentiate between the two kinds of claudication. ncbi.nlm.nih.gov/pmc/articles/P…
In your objective, you can take the lower limb pulses, do capillary refill and check how the skin looks. But the authors of this BMJ article reckon only the pulses are really of clinical significance bmj.com/content/360/bm…
In your referral letter, you can mention an ankle-brachial pressure index test. This tests to see if the blood pressure in the legs is lower than in the arms.
That’s it. If you want to learn more about haemodynamics I recommend @TaylorAlanJ 's TPMP here chewshealth.co.uk/tpmpsession8/ and @RogerKerry1 's Clinical Edge podcast here clinicaledge.co/podcast/physio…
Please let me know if anything I’ve written is not quite right. The main question I am left with is how common is this? Once in a year? Once in a career?
