Sirolimus-Induced Delayed Severe Thrombocytopenia After Liver Transplantation: A Case Report

Thrombocytopenia is a common condition in patients undergoing liver transplantation (LT). Thrombocytopenia is prevalent in early postoperative phase, and it gradually improves after several weeks. Delayed severe thrombocytopenia occurring after the initial recovery of platelets is rare. We report a case of a patient with delayed severe thrombocytopenia 59 weeks after LT.

Our patient was a 61-year-old man who presented to our institution 59 weeks after undergoing LT. He presented for removal of a bile duct stent that was inserted 3 months prior. Tacrolimus replaced sirolimus for immunosuppression during the seventh week after transplantation due to sirolimus-induced nephrotoxicity. On admission, the patient's vital signs were normal and his physical examination was unremarkable. Laboratory parameters demonstrated that the platelet (PLT) level was significantly decreased to 18 × 10⁹/L. PLTs reached a nadir of 3 × 10⁹/L even after utilization of interleukin-11, thrombopoietin, and low-dose prednisone. Although rare, sirolimus toxicity was suspected. Therefore, sirolimus was gradually replaced by cyclosporin A in combination with low-dose prednisone. Subsequently, a normal PLT level was gradually recovered. This study was approved by the ethical committee of the First Hospital of Jilin University and was performed in accordance with the ethical standards of the Helsinki Congress and Istanbul Declaration.

Recurrent delayed severe thrombocytopenia is rare after LT. Sirolimus toxicity might be a reason for its occurrence if other possible factors are excluded. After diagnosis, sirolimus therapy should be discontinued and patients should be treated with an alternative immunosuppressive regimen.