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

Tubulointerstitial involvement is well recognized in systemic lupus erythem atosus. The tubular dysfunction is usually latent and usually presents afte r diagnosis of systemic lupus erythematosus. We report a case presenting th at she is well previously and initially diagnosed as periodic paralysis of hypokalemia at emergency room and final diagnosis is systemic lupus erythem atosus with H+-ATPase pump defect of distal type renal tubular acidosis. Ki dney biopsy showed lupus nephritis classified as mesangial proliferative gl omerulonephritis WHO class IIB. Her renal tubular acidosis was subsided aft er steroid therapy was administered.