Diagnostic value of lower extremity ultrasonographic nerve enlargement for differentiating demyelinating Charcot-Marie-Tooth disease from chronic inflammatory demyelinating polyneuropathy.

BACKGROUND AND PURPOSE: We previously reported that nerve enlargement assessment by nerve ultrasonography of the intermediate upper limb is applicable for distinguishing demyelinating Charcot-Marie-Tooth disease (CMT) from chronic inflammatory demyelinating polyneuropathy (CIDP). However, differences in the severity and distribution patterns of lower extremity nerve enlargement have not been established for either disease. Therefore, we examined the utility of lower extremity nerve ultrasonography for differentiating between CMT and CIDP. METHODS: Twelve patients with demyelinating CMT and 17 patients with CIDP were evaluated. The median, ulnar, tibial, and fibular nerves were evaluated in three regions: the distal upper extremity, intermediate upper extremity, and lower extremity. Of the 14 selected screening sites, the number of sites that exhibited nerve enlargement (enlargement site number, ESN) in each region was determined. RESULTS: The screening ESNs in the intermediate region and lower extremities were greater in patients with demyelinating CMT than in patients with CIDP and greater than the ESN in the distal region (p = 0.010, p = 0.001, and p = 0.101, respectively). The ESNs in the intermediate region and lower extremities significantly differed among patients with typical CIDP, CIDP variants, and demyelinating CMT (p = 0.084 and p < 0.001). Among the 14 selected screening sites, the combined upper and lower extremity ESNs exhibited the highest AUC (0.92; p < 0.001). CONCLUSIONS: Combining the upper and lower extremities for ultrasonographic nerve measurement more accurately distinguishes CIDP from demyelinating CMT.

[Ultrasonographic diagnosis of inflammatory neuropathies].

Ultrasonographic nerve enlargement has primarily been reported in patients with inflammatory neuropathies such as chronic inflammatory demyelinating polyneuropathy (CIDP), multifocal motor neuropathy, Guillain-Barre syndrome, vasculitic neuropathy and leprosy. Nerve ultrasonography is a promising diagnostic supportive tool for inflammatory neuropathies. The ultrasonographic findings that are currently useful are 1) nerve enlargement primarily suggests the existence of inflammatory or demyelinating neuropathies and 2) for patients with CIDP or demyelinating Charcot-Marie-Tooth disease, the pattern of nerve enlargement is noted, and this pattern is useful for discriminating between these diseases. More precise evidence of ultrasonographic findings for inflammatory neuropathies should be established in the future.

[Ultrasonographic diagnosis of demyelinating neuropathy].

Ultrasonographic nerve enlargement has been reported in patients with demyelinating Charcot-Marie-Tooth disease, chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathy and POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome. Reference nerve sizes are needed at evaluation sites to determine nerve enlargement. However, neither site-based differences nor associations between the reference nerve sizes and several physical characteristics had been sufficiently verified. In our study, the reference nerve sizes of the median and ulnar nerves and the cervical nerve roots were determined in healthy Japanese adults. Site-based differences in the nerve sizes were observed. The stratification of reference nerve sizes according to gender is reasonable for practical use, as these differences reflect physical characteristics. The cross-sectional areas of the peripheral nerves were markedly larger at all evaluation sites in patients with demyelinating CMT than in patients with CIDP. However, the nerve sizes of the cervical nerve roots were not significantly different between patients with either disease. We also observed that the number of sites exhibiting nerve enlargement in the intermediate region of the median and ulnar nerves was useful to distinguish demyelinating CMT from CIDP. Thus, nerve ultrasonography is a promising diagnostic supportive tool for demyelinating neuropathy.

Ultrasonographic nerve enlargement of the median and ulnar nerves and the cervical nerve roots in patients with demyelinating Charcot-Marie-Tooth disease: distinction from patients with chronic inflammatory demyelinating polyneuropathy.

Demyelinating Charcot-Marie-Tooth disease (CMT) and chronic inflammatory demyelinating polyneuropathy (CIDP) are both demyelinating polyneuropathies. The differences in nerve enlargement degree and pattern at multiple evaluation sites/levels are not well known. We investigated the differences in nerve enlargement degree and the distribution pattern of nerve enlargement in patients with demyelinating CMT and CIDP, and verified the appropriate combination of sites/levels to differentiate between these diseases. Ten patients (aged 23-84 years, three females) with demyelinating CMT and 16 patients (aged 30-85 years, five females) with CIDP were evaluated in this study. The nerve sizes were measured at 24 predetermined sites/levels from the median and ulnar nerves and the cervical nerve roots (CNR) using ultrasonography. The evaluation sites/levels were classified into three regions: distal, intermediate and cervical. The number of sites/levels that exhibited nerve enlargement (enlargement site number, ESN) in each region was determined from the 24 sites/levels and from the selected eight screening sites/levels, respectively. The cross-sectional areas of the peripheral nerves were markedly larger at all evaluation sites in patients with demyelinating CMT than in patients with CIDP (p < 0.01). However, the nerve sizes of CNR were not significantly different between patients with either disease. When we evaluated ESN of four selected sites for screening from the intermediate region, the sensitivity and specificity to distinguish between demyelinating CMT and CIDP were 0.90 and 0.94, respectively, with the cut-off value set at four. Nerve ultrasonography is useful to detect nerve enlargement and can clarify morphological differences in nerves between patients with demyelinating CMT and CIDP.