Detection of neuropathy due to Mycobacterium leprae using noninvasive neurosensory testing of susceptible peripheral nerves

The prevalence of disability in patients with Hansen disease is related to peripheral nerve dysfunction. This dysfunction, which is due to chronic nerve compression, is the result of invasion of the peripheral nerve by Mycobacteria leprae. This suggests that early identification of M. leprae would be aided by detection of early stages of peripheral nerve compression. Traditional evaluation of peripheral nerve function with monofilaments, electrodiagnostic testing, or by observing motor palsy or digital ulcers unfortunately identifies only late sequelae of peripheral nerve dysfunction. The cutaneous pressure threshold required to identify 1 from 2 static-touch stimuli was obtained with the Pressure-Specified Sensory Device in upper and lower extremities of 51 patients who completed multidrug therapy for Hansen disease. Abnormal peripheral nerve function was identified in each patient and in each of the 120 bilateral nerves that were evaluated. The degree of nerve dysfunction included the range from early to late stages of nerve compression, suggesting that this method of neurosensory testing offers the possibility for early detection of peripheral nerve problems in Hansen disease.