Tubulointerstitial nephritis and uveitis with Fanconi syndrome in a patient with ankylosing spondylitis.

We report a 40-year-old man with ankylosing spondylitis who was referred to our hospital because of a 2-month history of general fatigue, anorexia, and weight loss. Laboratory findings showed anemia and renal dysfunction. Fanconi syndrome was suggested by multiple proximal tubular defects including renal glucosuria, hyperuricosuria, hyperphosphaturia, proximal renal tubular acidosis, and kaliuresis leading to hypokalemia. Renal biopsy showed acute tubulointerstitial nephritis. Furthermore, bilateral uveitis was diagnosed by an ophthalmologist. The patient was treated with systemic corticosteroids. The renal and proximal tubular function returned to normal and uveitis disappeared by 4 weeks after commencement of corticosteroid treatment. To our knowledge, tubulointerstitial nephritis and uveitis has rarely been associated with Fanconi syndrome and had not been reported in ankylosing spondylitis.