Ultrasonography of joint capsules and tendons in dialysis-related amyloidosis

Beta-2-microglobulin (beta 2m) amyloid infiltrates joint synovia, tendons and capsules. We report a cross-sectional ultrasonographic (US) evaluation of supraspinatus tendons' (SST) and femoral neck capsules' (FNC) thickness in 49 patients on long-term hemodialysis. Normal values for SST and FNC were defined in control subjects. Among the 49 patients, aged 21 to 86 (median 59) years at the time of US, dialyzed for 1 to 228 (median 97) months, 33 had at least one abnormal joint. The prevalence of patients with at least one or at least two abnormal joints, the number of abnormal joints per patient and the thickness of SST and FNC increased significantly with dialysis duration (P < 0.001 for all parameters considered). All (N = 11) patients with radiological and/or histological evidence of dialysis-related amyloidosis (DRA) had thickened SST and/or FNC. Twenty-two other patients without similar evidence of DRA also had thickened FNC and/or SST. Three died; post-mortem examination demonstrated that US abnormalities were due to beta 2m amyloid infiltration. We suggest that SST and FNC thickness, measured by US, is a useful, non-invasive tool for the diagnosis of DRA.