Carpal tunnel syndrome

Carpal tunnel syndrome is a common problem, which we encounter regularly in our GP consultations.¹ Accurate history taking and examination, as mentioned, can contribute in up to 70–90% of cases to a patient diagnosis.²,³ The authors¹ presented a decision tree incorporating the Phalen’s test as a diagnostic tool, which has a low diagnostic sensitivity (57%) and specificity (58%). Hansen et al even describe the Phalen test as being ‘useless’.⁴ Phalen test, Tinel sign, presence of thenar atrophy and history of nocturnal paraesthesia have little diagnostic value compared with history taking (84%) sensitivity/specificity 0.33%) and examination findings, for example weak thumb abduction (sensitivity 66%, specificity 66%). Nerve conduction studies can be used in patients with an intermediate pretest probability or in patients with an atypical presentation. They can also be used to quantify and stratify disease severity to aid in further treatment decision. In patients with a high probability of a carpal tunnel syndrome based on history and physical examination, nerve conduction studies are generally not indicated.

Evidence-based physical examination and history taking combined with clinical reasoning will improve the diagnostic outcome of consultation in general practice and will improve patients care and reduce unnecessary diagnostic testing. This will improve and speed up patients’ care and will save the NHS money in the long run. Teaching of evidence-based physical examination and clinical reasoning need to be formally introduced into the medical student’s curriculum.⁵

• © British Journal of General Practice 2014