Fractional excretion magnesium (FE Mg) in systemic lupus erythematosus.

BACKGROUND Tubulointerstitial fibrosis is an index of clinical severity. FE Mg has been delineated to correlate directly with the magnitude of tubulointerstitial fibrosis in clinical setting of glomerulonephropathy. A correlation between FE Mg tubulointerstitial fibrosis has never been assessed in nephritis associated with systemic lupus erythematosus. MATERIAL AND METHOD Thirty-six patients diagnosed of having lupus nephritis were included for the determination of renal functions namely creatinine clearance, FE Mg, urinary protein. Of these 36 patients, 18 patients were associated with intact tubulointerstitial structure (group I) and 18 age matched patients were associated with tubulointerstitial fibrosis (group II) RESULTS: The mean FE Mg observed in group I was 1.5 +/- 0.3 which differed significantly from that observed in group II; 2.6 +/- 1; p = 0.006. CCr, total urinary protein, systolic and diastolic pressure were not significantly different between the two groups. CONCLUSION FE Mg is a sensitive marker for the detection of tubulointerstitial disease in lupus nephritis. It is useful in early screening of disease severity in systemic lupus erythematosus.