Immunotherapy related acute kidney injury

Immunotherapy has become a crucial cancer treatment, showing effectiveness in various types of cancer. However, as the use of immunotherapy increases, so does the occurrence of related side effects. The incidence of immunotherapy-associated acute kidney injury (AKI) is 2.2%1, making it a relatively infrequent complication. On the other hand, AKI is a common presentation in acute medical settings, highlighting the importance of promptly recognising and managing immunotherapy-related AKI in patients receiving this treatment. A 46-year-old male with a background of clear cell renal cell cancer and left nephrectomy in March 2023, and he had been receiving adjuvant Pembrolizumab immunotherapy for three cycles. The patient presented with generally feeling unwell and urinary frequency. On examination, the patient was afebrile with normal vital signs and unremarkable physical findings. Laboratory investigations unveiled acute kidney injury stage 32, characterised by a rise in serum creatinine levels to 361 µmol/L from a baseline of 131 µmol/L. While the full blood count remained within normal range, C-reactive protein (CRP) levels were elevated at 138 mg/L. The patient had not initiated any new medications recently and had no recent exposure to nephrotoxins. Considering these findings, the patient was initially treated with antibiotics and intravenous fluid for possible infection. Despite initial treatment, the patient's kidney function worsened on the following day, as indicated by a rise in the creatinine level to 370 µmol/L. Blood and urine cultures were performed, but no organisms were isolated from both samples. Urine microscopy findings showed sterile pyuria. His urine albumin creatinine ration did not show any nephrotic range proteinuria. Viral screenings for influenza and COVID-19 were negative. Renal ultrasound imaging revealed a normal right kidney without any signs of blockage or obstruction. Furthermore, a chest X-ray did not show any pulmonary pathology. This raised concerns about the possibility of immunotherapy-related nephritis. After discussion with the oncology team, it was decided to initiate intravenous Methylprednisolone 1 mg/kg to address the suspected immunotherapy related nephritis. After initiating intravenous methylprednisolone, the patient's renal function showed progressive improvement, with the serum creatinine decreasing to 227 µmol/L (AKI stage 1)2 after the third dose of methylprednisolone. Consequently, we transitioned to oral steroid therapy and began tapering the dose gradually. The patient was discharged from the hospital under this regimen. During follow-up reviews, the patient's renal function continued to improve, although his creatinine level remained around 150 µmol/L. Our assessment suggests that this is likely his new baseline renal function. It is challenging to differentiate between immunotherapy and other causes of AKI in the acute setting. It is very important to consider immunotherapy-related AKI, particularly when renal function is worsening despite appropriate initial management and after excluding obstructive pathology. This case highlights the importance of considering immunotherapy-related nephritis in the differential diagnosis of AKI for every patient who has undergone immunotherapy. It is also important to seek early opinion from the oncology team for any cases suspected of immunotherapy-related complications. Cortazar F.B, Marrone K.A, Troxell M.L. et al. Clinicopathological features of acute kidney injury associated with immune checkpoint inhibitors. Kidney International 2016;90: 638-647 KDIGO Guidelines. 2012 AKI Guidelines. kdigo.org/guidelines/acute-kidney-injury/