Systemic lupus erythematosus presenting initially as hydrogen ATPase pump defects of distal renal tubular acidosis

Tubulointerstitial involvement is well recognized in systemic lupus erythematosus. The tubular dysfunction is usually latent and usually presents after diagnosis of systemic lupus erythematosus. We report a case presenting that she is well previously and initially diagnosed as periodic paralysis of hypokalemia at emergency room and final diagnosis is systemic lupus erythematosus with H⁺-ATPase pump defect of distal type renal tubular acidosis. Kidney biopsy showed lupus nephritis classified as mesangial proliferative glomerulonephritis WHO class II B. Her renal tubular acidosis was subsided after steroid therapy was administered.