Endoneurial edema in sural nerve may indicate recent onset inflammatory neuropathy

: Sural nerve biopsy is an important means of establishing the diagnosis of inflammatory neuropathies. We investigated the diagnostic value of endoneurial edema. Methods : Diagnostic sural nerve biopsies from 42 patients with inflammatory and 28 patients with noninflammatory neuropathies were re‐evaluated for the presence of endoneurial edema. Edema was assessed on hematoxylin‐eosin stained paraffin and frozen sections and on azure II‐methylene blue stained semithin sections. We determined the area of endoneurial edema on digitized images in relation to the entire endoneurial area of each fascicle. Results : Edema was more extensive in neuropathies with short disease duration (≤12 months) as compared to long duration (>12 months; P <  0.01). Edema in inflammatory neuropathies of ≤12 months duration covered a larger area than in noninflammatory neuropathies ( P <  0.01), and the extent of edema correlated negatively with disease duration ( P <  0.05). Conclusions : Endoneurial edema may be a useful additional disease marker in inflammatory neuropathies of recent onset. Muscle Nerve 53 : 705–710, 2016