A Case of Cytokine Release Syndrome (CRS) Related to Treatment With Lenvatinib Plus Pembrolizumab for Metastatic Clear Cell Renal Cell Carcinoma.

INTRODUCTION

Cytokine release syndrome (CRS) is a systemic inflammatory response triggered by various factors, including infection and immunotherapy. Due to its nonspecific presentation, distinguishing CRS from other life-threatening conditions remains challenging.

CASE PRESENTATION: A 79-year-old male receiving lenvatinib plus pembrolizumab for metastatic renal cell carcinoma presented with high-grade fever, altered mental status, and respiratory failure on day 4 of treatment. After excluding infectious etiologies and endocrine dysfunction, CRS was suspected and confirmed by elevated interleukin-6 levels. Lenvatinib and pembrolizumab were discontinued, and the patient was treated with tocilizumab and dexamethasone. Clinical improvement was achieved by day 7.

CONCLUSION

CRS should be considered a potential cause of unexplained shock in patients receiving immune checkpoint inhibitors. Early diagnostic consideration is vital for timely intervention.