Amyloid arthropathy in a dialysis patient.

The patient was a 66-year-old man who had undergone hemodialysis for 20 years. He had suffered from right hip pain for several months. He could stand, but his walking endurance was poor. Plain radiograph of the right hip showed osteoporotic change. T1-weighted (Fig. A) and TI inversion recovery MRI images (Fig. B) of bilateral hips showed low-signal-intensity thickened synovium (long arrows) causing osseous erosion at the ‘bare areas’ of bilateral proximal femur which is unprotected by articular cartilage. The femoral bone marrow lesions (short arrows), in contrast, are hyperintense signal on TI inversion recovery image. Dialysis-related amyloidosis was the impression. Follow-up laboratory tests revealed elevated serum beta2 microglobulin levels (21.4 mg/L; reference range, 0.6 to ~2.4 mg/L). The patient’s treatment was changed to four-hour dialysis, using high-flux cellulose-derived dialysis membranes, at a low blood-flow rate (200 mL/min) in order to remove greater quantities of beta2-microglobulin. The patient’s walking endurance improved gradually.