[How to detect neuropathy in leprosy].

In leprosy, the early detection of peripheral nerve damage is essential for the prevention of disability. To date, there is no consensus on what is the best clinical test to reveal such abnormalities. In this prospective study we examined the effectiveness of five clinical tests to assess radial cutaneous nerve (RCN) damage (the most frequently involved). Light touch was assessed by two nylon threads (based on the Semmes-Weinstein monofilaments testing technique) bent on the skin at a pressure of 0.5 (N. 4 nylon) and 0.2 gram (N. 5 nylon). Pinprick and cooling sensations were examined by a needle and a drop of ether. The nerve thickness was assessed by palpation. Sensory findings were then compared to sensory nerve conduction values of the RCN and a sensitivity analysis was performed. The patient group consisted of 108 consecutive new leprosy sufferers (138 RCN) who attended the Institut de Léprologie Appliquée de Dakar during one year. Diagnosis and classification were based on Ridley and Jopling's criteria (clinical examination, skin smears and biopsy). Normal values were determined among 22 healthy subjects (44 RCN). The best tests in term of sensitivity were palpation (.60), N. 5 nylon (.65) and N. 5 + palpation (.79). Their positive predictive values were .84 (palpation), .94 (N. 5 nylon) and .83 (N. 5 + palpation). The best tests in term of area under the curve were palpation (.66), N. 5 nylon (.71) and N. 5 + palpation (.78). The results remain the same for the lepromatous or tuberculoid leprosy patients.(ABSTRACT TRUNCATED AT 250 WORDS)