[Two cases of lupus cystitis complicated by lupus nephritis treated successfully with steroid therapy].

In patients with systemic lupus erythematosus(SLE), interstitial cystitis(lupus cystitis) is an uncommon, but important manifestation. We report two Japanese patients with lupus cystitis. Case 1 was a 49-year-old woman diagnosed as having rheumatoid arthritis and membranous nephropathy. She was treated with prednisolone(5 mg daily). Case 2 was a 41-year-old woman also diagnosed as having rheumatoid arthritis previously and treated with a non-steroidal anti-inflammatory drug. Both cases presented abdominal pain, vomiting, dysuria and frequency of micturition. We diagnosed these cases as SLE on the basis of arthritis, renal disorder(proteinuria and hematuria), and positive antinuclear and anti-dsDNA antibodies. In addition, bilateral hydronephrosis was found in both cases. Thus, they were also diagnosed as probable lupus cystitis. The patients were treated with one cycle of methylprednisolone pulse therapy. Thereafter they were treated with 60 mg/day of prednisolone and their symptoms resolved promptly. Furthermore, no abnormal finding was found by abdominal ultrasonography and/or the intravenous pyelogram after therapy. Renal biopsies were performed and both cases showed lupus glomerulopathy (case 1: WHO class Vb, case II: WHO class IVb). Abdominal pain and/or dysuria, which is common in SLE patients, requires further examinations to evaluate the lupus cystitis.