Does a carpal tunnel syndrome predict an underlying disease?

Carpal tunnel syndrome (CTS) may be the presenting symptom of an underlying disease such as diabetes mellitus, hypothyroidism or connective tissue disease (CTD). It was investigated whether additional blood tests (glucose level, thyroid-stimulating hormone level and erythrocyte sedimentation rate) are useful to detect diabetes mellitus, hypothyroidism or CTD in patients with CTS who have not been diagnosed with these diseases before. A group of 516 consecutive patients electromyographically diagnosed with CTS without known diabetes mellitus, hypothyroidism or CTD underwent blood tests and were followed up for incident diabetes mellitus, hypothyroidism or CTD to investigate whether these additional blood tests are useful to detect these diseases in patients with CTS. In our CTS population, only two patients were newly diagnosed with diabetes mellitus, two with hypothyroidism and none with CTD. In general, systematic screening for incident diabetes mellitus, hypothyroidism and CTD through additional blood tests seems to be of little additional value in otherwise typical cases of CTS.