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Early diagnosis of neuropathy in leprosy--comparing diagnostic tests in a large prospective study (the INFIR cohort study).
PLoS Negl Trop Dis. 2008 Apr 02; 2(4):e212.PN

Abstract

BACKGROUND

Leprosy is the most frequent treatable neuromuscular disease. Yet, every year, thousands of patients develop permanent peripheral nerve damage as a result of leprosy. Since early detection and treatment of neuropathy in leprosy has strong preventive potential, we conducted a cohort study to determine which test detects this neuropathy earliest.

METHODS AND FINDINGS

One hundred and eighty-eight multibacillary (MB) leprosy patients were selected from a cohort of 303 and followed for 2 years after diagnosis. Nerve function was evaluated at each visit using nerve conduction (NC), quantitative thermal sensory testing and vibrometry, dynamometry, monofilament testing (MFT), and voluntary muscle testing (VMT). Study outcomes were sensory and motor impairment detected by MFT or VMT. Seventy-four of 188 patients (39%) had a reaction, neuritis, or new nerve function impairment (NFI) event during a 2-year follow-up. Sub-clinical neuropathy was extensive (20%-50%), even in patients who did not develop an outcome event. Sensory nerve action potential (SNAP) amplitudes, compound motor action potential (CMAP) velocities, and warm detection thresholds (WDT) were most frequently affected, with SNAP impairment frequencies ranging from 30% (median) to 69% (sural). Velocity was impaired in up to 43% of motor nerves. WDTs were more frequently affected than cold detection thresholds (29% versus 13%, ulnar nerve). Impairment of SNC and warm perception often preceded deterioration in MF or VMT scores by 12 weeks or more.

CONCLUSIONS

A large proportion of leprosy patients have subclinical neuropathy that was not evident when only MFT and VMT were used. SNC was the most frequently and earliest affected test, closely followed by WDT. They are promising tests for improving early detection of neuropathy, as they often became abnormal 12 weeks or more before an abnormal monofilament test. Changes in MFT and VMT score mirrored changes in neurophysiology, confirming their validity as screening tests.

Authors+Show Affiliations

Royal Tropical Institute (KIT), Amsterdam, The Netherlands. w.v.brakel@kit.nlNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18382604

Citation

van Brakel, Wim H., et al. "Early Diagnosis of Neuropathy in Leprosy--comparing Diagnostic Tests in a Large Prospective Study (the INFIR Cohort Study)." PLoS Neglected Tropical Diseases, vol. 2, no. 4, 2008, pp. e212.
van Brakel WH, Nicholls PG, Wilder-Smith EP, et al. Early diagnosis of neuropathy in leprosy--comparing diagnostic tests in a large prospective study (the INFIR cohort study). PLoS Negl Trop Dis. 2008;2(4):e212.
van Brakel, W. H., Nicholls, P. G., Wilder-Smith, E. P., Das, L., Barkataki, P., & Lockwood, D. N. (2008). Early diagnosis of neuropathy in leprosy--comparing diagnostic tests in a large prospective study (the INFIR cohort study). PLoS Neglected Tropical Diseases, 2(4), e212. https://doi.org/10.1371/journal.pntd.0000212
van Brakel WH, et al. Early Diagnosis of Neuropathy in Leprosy--comparing Diagnostic Tests in a Large Prospective Study (the INFIR Cohort Study). PLoS Negl Trop Dis. 2008 Apr 2;2(4):e212. PubMed PMID: 18382604.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Early diagnosis of neuropathy in leprosy--comparing diagnostic tests in a large prospective study (the INFIR cohort study). AU - van Brakel,Wim H, AU - Nicholls,Peter G, AU - Wilder-Smith,Einar P, AU - Das,Loretta, AU - Barkataki,Pramila, AU - Lockwood,Diana N J, AU - ,, Y1 - 2008/04/02/ PY - 2007/10/22/received PY - 2008/02/12/accepted PY - 2008/4/3/pubmed PY - 2010/3/10/medline PY - 2008/4/3/entrez SP - e212 EP - e212 JF - PLoS neglected tropical diseases JO - PLoS Negl Trop Dis VL - 2 IS - 4 N2 - BACKGROUND: Leprosy is the most frequent treatable neuromuscular disease. Yet, every year, thousands of patients develop permanent peripheral nerve damage as a result of leprosy. Since early detection and treatment of neuropathy in leprosy has strong preventive potential, we conducted a cohort study to determine which test detects this neuropathy earliest. METHODS AND FINDINGS: One hundred and eighty-eight multibacillary (MB) leprosy patients were selected from a cohort of 303 and followed for 2 years after diagnosis. Nerve function was evaluated at each visit using nerve conduction (NC), quantitative thermal sensory testing and vibrometry, dynamometry, monofilament testing (MFT), and voluntary muscle testing (VMT). Study outcomes were sensory and motor impairment detected by MFT or VMT. Seventy-four of 188 patients (39%) had a reaction, neuritis, or new nerve function impairment (NFI) event during a 2-year follow-up. Sub-clinical neuropathy was extensive (20%-50%), even in patients who did not develop an outcome event. Sensory nerve action potential (SNAP) amplitudes, compound motor action potential (CMAP) velocities, and warm detection thresholds (WDT) were most frequently affected, with SNAP impairment frequencies ranging from 30% (median) to 69% (sural). Velocity was impaired in up to 43% of motor nerves. WDTs were more frequently affected than cold detection thresholds (29% versus 13%, ulnar nerve). Impairment of SNC and warm perception often preceded deterioration in MF or VMT scores by 12 weeks or more. CONCLUSIONS: A large proportion of leprosy patients have subclinical neuropathy that was not evident when only MFT and VMT were used. SNC was the most frequently and earliest affected test, closely followed by WDT. They are promising tests for improving early detection of neuropathy, as they often became abnormal 12 weeks or more before an abnormal monofilament test. Changes in MFT and VMT score mirrored changes in neurophysiology, confirming their validity as screening tests. SN - 1935-2735 UR - https://www.unboundmedicine.com/medline/citation/18382604/Early_diagnosis_of_neuropathy_in_leprosy__comparing_diagnostic_tests_in_a_large_prospective_study__the_INFIR_cohort_study__ DB - PRIME DP - Unbound Medicine ER -