An unusual cause of non-infectious peritonitis in a peritoneal dialysis patient

We report a 48-year-old woman with end-stage renal disease receiving continuous ambulatory peritoneal dialysis who presented with polyarthritis. Painless cloudy peritoneal dialysis effluent was also noted incidentally. Analyses of the effluent dialysate showed increased leukocyte count with a predominance of lymphocytes. Empirical intraperitoneal cefazolin was given initially. Routine cultures of effluent dialysate were negative for bacteria, fungi, and mycobacteria. Cytology revealed no malignant cells. However, the turbidity of effluent dialysate was still increased after 1 week of antibiotic treatment. In the meantime, laboratory tests showed significant antinuclear antibody positivity. Additional serology testing found positive antihistone antibody. On reviewing the patient's current medications, we found that she had been taking hydralazine for the past 3 months. Because drug-induced lupus was suspected, hydralazine was discontinued and low-dose steroids were initiated. Clinical symptoms and cloudy dialysate rapidly abated afterwards. There was no relapse of arthralgia during the next 1-year period of follow-up.