Diagnostic validity of skin biopsy in painful sensory neuropathy utilising intra- and subepidermal nerve fiber densities
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| Year of publication | 2006 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Evaluation of intra-epidermal nerve fiber density (IENFD) has become a standard tool in the diagnosis of painful sensory neuropathy. However, changes in the density of the subepidermal nerve plexus (SENFD) have never been systematically studied in neuropathy patients. Intra- and subepidermal nerve fiber densities were examined using PGP 9.5-immunostaining of skin-punch biopsy samples from the distal calf in 99 consecutively-recruited patients with clinical symptoms of a painful sensory neuropathy and with abnormal thermal thresholds on quantitative sensory testing (QST), and in 37 age-matched healthy volunteers. Comparison of the groups demonstrated a clear reduction in both IENFD and SENFD in the neuropathy group compared to the healthy controls (p<0.001). The diagnostic validity of IENFD and SENFD was assessed in receiver-operating characteristic curve (ROC) analysis. Using a cut-off value of 8.8 fibers/mm, the sensitivity of IENFD examination was 0.80 and the specificity 0.82. Evaluation of SENFD reached a sensitivity of 0.81 and a specificity of 0.88 for 7.25% as a cut-off point. The neuropathic group was further divided into two patient subgroups – pure SFN (pSFN) and mixed neuropathy subgroups (MFN) with concomitant nerve conduction abnormalities. Comparing these subgroups, no significant differences in intraepidermal innervation were found (p = 0.243), while the SENFD was markedly more reduced in patients with MFN (p<0.001). Despite close correlation between subepidermal and intra-epidermal nerve fiber densities, the ROC curve of the SENFD values allowed discrimination between pSFN and MFN patients. |
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