Intraepidermal nerve fibre density in POEMS (Crow-Fukase) syndrome and the correlation with sural nerve pathology.

ABSTRACT

OBJECTIVE: To examine intraepidermal nerve fibre densities (IENFDs) in patients with polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy and skin change (POEMS) syndrome. METHODS: The IENFDs of 11 patients with POEMS syndrome were estimated. We determined whether IENFD was associated with patient clinical features or the estimated number of nerve fibres on complete cross-sections of biopsied sural nerves. RESULTS: IENFD was significantly reduced (9.7±4.4fibres/mm) compared with normal controls (p<0.05), although the individual values varied from 1.4 to 14.4fibres/mm. The presence of glucose intolerance was significantly associated with a reduction of IENFD (p<0.05). The number of unmyelinated fibres was preserved at the sural nerve level and was not correlated with IENFD. In contrast, the number of myelinated fibres was correlated with IENFD (p<0.05). CONCLUSIONS: Some of the patients presented with a severe IENFD reduction. Because the number of unmyelinated fibres was well preserved at the level of the sural nerve biopsy, this severe reduction may indicate involvement at the most distal nerve terminals of unmyelinated fibres. Although the reduction of IENFD becomes evident as polyneuropathy becomes severe, the effects of glucose intolerance should also be considered in patients with moderate to severe reductions.