Kidney Week

Abstract: SA-PO1179

Sirolimus-Induced Chylothorax in a Kidney Transplant Recipient

Session Information

• Transplantation: Clinical - Complications, Pediatrics, and Multi-Organ Considerations
  October 24, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

• 2002 Transplantation: Clinical

Authors

• Naseeb, Muhammad, SUNY Upstate Medical University, Syracuse, New York, United States

Muhammad Naseeb, MBBS

• Irfan, Babar, SUNY Upstate Medical University, Syracuse, New York, United States

Babar Irfan, MD, MBBS

• Alqudah, Zain Mohamad, SUNY Upstate Medical University, Syracuse, New York, United States

Zain Mohamad Alqudah, MD

• Zafar, Mohsin, SUNY Upstate Medical University, Syracuse, New York, United States

Mohsin Zafar, MD

• Ali, Shehzad, SUNY Upstate Medical University, Syracuse, New York, United States

Shehzad Ali, MD

Introduction

Sirolimus, a mTOR inhibitor, is utilized in kidney transplantation to mitigate calcineurin inhibitor-related nephrotoxicity. While its side-effect profile including impaired wound healing and interstitial pneumonitis—is documented, chylothorax is an exceedingly rare complication. Chylothorax typically results from thoracic duct trauma or malignancy; however, mTOR inhibitors may cause lymphatic dysfunction by inhibiting lymphangiogenesis. In transplant patients this is further complicated by the risk of opportunistic infections, such as Pneumocystis jirovecii pneumonia (PJP), which can mimic drug-induced pulmonary toxicity. We present a case of a kidney transplant recipient who developed bilateral chylothorax and concurrent PJP following a transition to sirolimus.

Case Description

A 62-year-old male with a 2017 DCD kidney transplant (primary disease: hypertensive nephrosclerosis and chronic analgesic nephropathy) presented in December 2025 with progressive dyspnea. He was maintained on sirolimus, tacrolimus, and prednisone. Sirolimus was initiated in 2019 following mycophenolate mofetil-induced leukopenia.
Admitted with acute hypoxic respiratory failure and AKI. Chest CT revealed worsening bilateral ground-glass opacities and bilateral pleural effusions. Thoracentesis and chest tube drainage confirmed bilateral chylous effusions. A Karius study confirmed concurrent PJP. Fungitell was >500. Sirolimus was discontinued. The patient was treated with octreotide for chylothorax and atovaquone for PJP and a taper dose of steroids as per pulmonology. The patient demonstrated respiratory improvement and was successfully weaned from high-flow oxygen.

Discussion

This case highlights a rare diagnostic challenge: the coexistence of sirolimus-induced lymphatic complications and opportunistic infection . mTOR inhibitors can interfere with signaling pathways essential for lymphatic endothelial cell survival, leading to "leaky" vessels and chylothorax. Concurrent PJP infection, confirmed via Karius study, underscores the necessity of a broad differential. While the chylous effusion pointed toward sirolimus toxicity, the ground-glass opacities and elevated Fungitell necessitated the exclusion of PJP. For the nephrologist, sirolimus-induced chylothorax must remain on the differential for unexplained pleural effusions once malignancy is ruled out. Resolution requires cessation of the mTOR inhibitor alongside supportive measures like octreotide.