Tacrolimus-associated hemolytic uremic syndrome: A case analysis

Background: Tacrolimus is an effective organ transplantation immunosuppressant. Hemolytic uremic syndrome (HUS) is a rare but severe complication of tacrolimus. Methods: We report a case of tacrolimus-associated HUS and review the 15 previously reported cases. Results: The results of the 16 cases indicated that tacrolimus-associated HUS is more frequent in females (56.3%), with the mean age at onset of 41.3 years. Forty-four percent of cases received renal transplantations. The average time from the first tacrolimus dose to HUS onset was 7.1 months. Prevalence was between 0.1-4.7%. The tacrolimus trough level did not predict the prognosis. Seven patients (43.7%) had improved graft function after treatment, including anticoagulation and antiplatelet therapy, reduction or discontinuation of tacrolimus, switch to cyclosporine (CyA), plasma exchange (PE) and dialysis. Five patients (31.3%) died and four patients (25%) lost their graft in spite of the above treatment. Mortality risk factors for transplant recipients with tacrolimus-associated HUS included: (1) non-renal transplant recipients (100% vs. 36.4%, p=0.034); (2) lower peak serum Cr (2.58 ± 1.23 vs. 6.16 ± 1.96, p<0.002); (3) liver dysfunction (60% vs. 0, p<0.02); (4) higher serum lactate dehydrogenase (LDH) level (3119 ± 1019 vs. 982 ± 522, p<0.001). A lower platelet count carried borderline mortality risk (29500 ± 14480 vs. 59625 ± 25584, p=0.057). Conclusions: HUS should be included in the differential diagnosis of renal function deterioration in patients on tacrolimus post-organ transplantation. Frequent renal function monitoring and appropriate treatment should be performed aggressively to decrease morbidity and mortality, especially in patients with risk factors.