Sulfasalazine-Induced Crystalluria Causing Severe Acute Kidney Injury.

Sulfasalazine is an anti-inflammatory agent commonly used in the treatment of autoimmune conditions such as inflammatory bowel disease and rheumatoid arthritis. Sulfasalazine is converted by gut bacteria into sulfapyridine and the clinically active metabolite 5-aminosalicylic acid (5-ASA), and its efficacy is proportional to the 5-ASA concentration within the intestinal lumen. Renal complications are commonly reported for the chemically similar 5-ASA derivative mesalamine, but are not well-known side effects of sulfasalazine therapy. We report a 72-year-old patient with Crohn's disease managed with sulfasalazine for more than 10 years who presented with severe acute kidney injury (serum creatinine, 9.7mg/dL). Renal ultrasound revealed calculi and he subsequently spontaneously voided innumerable stones, which were composed of sulfasalazine metabolites. His renal calculi cleared and serum creatinine concentration improved to 3.1mg/dL after discontinuing sulfasalazine therapy and intravenous fluid hydration. His kidney function eventually returned to baseline. This case demonstrates that renal complications, in particular nephrolithiasis, may be an under-reported but potentially serious phenomenon in patients with inflammatory bowel disease treated with sulfasalazine and that their hydration status may play an important role in this process.

Immune thrombocytopenia in 2 healthy young women after the Pfizer-BioNTech BNT16B2b2 messenger RNA coronavirus disease 2019 vaccination.

Immune thrombocytopenic purpura (ITP) is a rare complication associated with vaccines targeting various diseases, including influenza, measles-mumps-rubella, hepatitis B, and diphtheria-tetanus-pertussis. We report 2 cases of ITP in healthy 20-year-old and 21-year-old women presenting to Emory University in Atlanta, GA, 2 days after the second dose and 11 days after the first dose (respectively) of the Pfizer-BioNTech messenger RNA severe acute respiratory syndrome coronavirus 2 vaccine. Both patients recovered quickly. With more than a billion doses of coronavirus disease 2019 vaccines safely administered worldwide as of May 2021, discussions with patients should put into perspective the low risks of vaccination against the enormous societal benefit of the coronavirus disease 2019 vaccine.