P29-F Intraneural collateral circulation in the median nerve mimicking carpal tunnel syndrome

Abstract

Background Patients with end stage kidney disease under dialysis treatment are often referred to neurophysiological examination with the suspicion of CTS (carpal tunnel syndrome). Previously only 1 case was reported, where CTS was mimicked by proximal median nerve damage and intraneural collateral circulation in a patient with radiocephalic fistula. (N. Wolfram et al. 2014) Material and methods We reviewed the EDX (electrodiagnostic studies) and HRU (High resonance ultrasonography) findings in 7 patients with AVF(arteriovenous fistula): 6 with radiocephalic fistula and 1 with brachiocephalic fistula, with the clinical presentation of CTS. Results All 7 patients presented pain and paraesthesias in the thumb, 4 of them described worsening during the dialysis sessions. 6 patients had DM in their medical history. EDX showed signs of axonal PNP in 4 patients, in 2 patients sensory and motor changes were found in n. medianus, not consistent with CTS, 1 patient was not examined by EDX because of an ICD unit. HRU: all 6 patients with radiocephalic fistula presented intraneural hypervascularization and collateral circulation in the ipsilateral n. medianus. No similar changes were observed in the patient with brachiocephalic fistula. Conclusions Intraneural collateral circulation in the median nerve was a consistent finding in patients with radiocephalic fistula, but was not seen in the patient with brachiocephalic fistula. Further studies are required to determine the causative agent and the precise relationship to radiocephalic fistula.