Background The prevalence of subclinical neuropathy in Rheumatoid Arthritis (RA) is 65-85% (1). It has been shown that RA patients may have electrophysiological or histological abnormalities even in the absence of clinical symptoms or signs of peripheral nerve involvement (2).
Objectives To determine whether median cross-sectional area (m-CSA) and ulnar CSA (u-CSA) at wrist level differ between RA patients without signs and symptoms of median and ulnar neuropathy and healthy controls
Methods The study is approved by local ethics committee of Gazi University. To achieve a difference of 2.8 mm2 in m-CSA measures between RA patients and controls with an alpha error of 0.05 and 80% power, we planned to enroll 38 subjects in each group (3). Thirty-eight RA patients without signs and symptoms of median and ulnar neuropathy and 38 healthy controls were enrolled into study. All patients and controls were included in ultrasonographic assessment (General Electric Logiq P5, 8-12 MHz high frequency transducer). M-CSA and u-CSA were measured at the proximal inlet of the carpal tunnel using the pisiform bone as landmark. Comparison of numerical data between groups were analysed using independent-samples t test. The areas of the dominant side were used for correlation analysis by using Pearson correlation test.
Results There was no difference in m-CSA and u-CSA measures between RA patients and controls (Table 1). There was no significant correlation between CSA measures of dominant hand and patient characteristics (age, height, weight, disease duration). In %24 of RA patients and %14 of controls m-CSA was above 10 mm2. The differenece was not statistically significant (p=0.20).
Conclusions We found similar ultrasonographic m-CSA and u-CSA values in RA patients and healthy controls. Nonetheless, these results can not exclude subclinical neurological involvement in RA patients without signs and symptoms of median and ulnar neuropathy.
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Lanzillo B, Pappone N, Crisci C, di Girolamo C, Massini R, Caruso G. Subclinical peripheral nerve involvement in patients with rheumatoid arthritis. Arthritis Rheum. 1998 Jul;41(7):1196-202
Sarría L, Cabada T, Cozcolluela R, Martínez-Berganza T, García S. Carpal tunnel syndrome: usefulness of sonography. Eur Radiol. 2000;10(12):1920-5
Disclosure of Interest None Declared