Cyclosporine induced nephrotoxicity in renal transplant recipients: clinical significance of fractional excretion of sodium, potassium and magnesium.
OBJECTIVE
Evaluation of fractional excretion of Sodium, Potassium and Magnesium as indicators of cyclosporine (CsA) toxicity in de-novo renal transplant recipients.


METHODS
A prospective study was conducted on 59 live related renal allograft recipients. Fractional excretion(FE) of sodium (Na+), potassium (K+) and magnesium (Mg2+) were calculated on day 1, 3, 5 and 10 post transplant. Graft dysfunctions were evaluated by colour-Doppler, CsA levels and renal biopsy. Normal ranges were determined on 30 healthy subjects.


RESULTS
The mean creatinine on day 1 was 3.1 +/- 1.3 mg/dl and declined to 1.6 +/- 1.2 on day 10. FE of Na+, K+ and Mg2+ were 12 +/- 9%, 34 +/- 20% and 13 +/- 10% respectively on day 1 and reduced to 2.2 +/- 2%, 11 +/- 14% and 11 +/- 14% on day 10. Of the 59 recipients, 38 (64%) had uneventful recovery (group A), 21(36%) had graft dysfunction [6 acute rejection (group B) and 15 either acute tubular necrosis or high CsA(group C)]. In group A, on day 1, FENa+, FEK+ and FEMg2+ were 5 +/- 4%, 24 +/- 12% and 6.6 +/- 3% respectively and these declined to 1.2 +/- 0.6%, 4.6 +/- 0.7% and 6 +/- 3% respectively on day 10. Compared to group A, group C had significantly high values on day 1, FENa+ 15 +/- 8%, FEK+ 36 +/- 24% and FEMg2+ 21 +/- 10% (p < 0.0001) and on day 10, FENa+ 3.7 +/- 2.7%, FEK+ 20 +/- 15% and FEMg2+ 15 +/- 8% (p < 0.05). In the group B, day 1 and day 10 levels were FENa+ 6 +/- 3%, FEK+ 26 +/- 13% and FEMg2+ 7 +/- 2.8% and FENa+ 1.2 +/- 0.7%, FEK+ 4.2 +/- 0.5%, FEMg2+ 7 +/- 4% respectively. CsA levels and AUC did not correlate with CsA toxicity.


CONCLUSIONS
FE of magnesium is a useful marker of CsA toxicity independent of CsA blood levels. FE studies can supplement renal biopsy findings.
Naqvi
Haider Nawaz
HN
Sindh Institute of Urology and Transplantation (SIUT), Dow Medical College and Civil Hospital, Karachi.
Zafar
Mirza Naqi
MN
Hussain
Amna
A
Naqvi
Syed Ali Anwar
SA
Rizvi
Adibul Hassan
AH
D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism*; D002648:Child; D003404:Creatinine / Q000378:metabolism; D003430:Cross-Sectional Studies; D016572:Cyclosporine / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D007674:Kidney Diseases / Q000139:chemically induced / Q000378:metabolism*; D016030:Kidney Transplantation; D008274:Magnesium / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000378:metabolism; D011446:Prospective Studies; D012964:Sodium / Q000378:metabolism; D013997:Time Factors
D015415:Biomarkers; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D012964:Sodium; D003404:Creatinine; D008274:Magnesium; D011188:Potassium