What happened, in summary

This 59-year-old man was admitted to nephrology on April 1, 2024, after more than 6 months of frothy urine. He had been diagnosed with Stage IIIA right lung adenocarcinoma in February 2021 and underwent surgery in March 2021. In September 2023, the cancer recurred with subcarinal lymph node and pleural metastases. He then received bevacizumab 500 mg every 3 weeks. After starting bevacizumab, he developed new hypertension with systolic blood pressure up to 180 mmHg, peripheral edema, and persistent frothy urine. Kidney function worsened over serial testing: creatinine rose from 99 µmol/L in November 2023 to 136.9 µmol/L in March 2024, proteinuria increased, and serum albumin fell. Bevacizumab was reduced to 400 mg every 4 weeks in December 2023 and stopped in February 2024. On admission, 24-hour urine protein was 4617.6 mg, serum creatinine was 156 µmol/L, eGFR was 41.27 mL/min/1.73 m², albumin was 23.2 g/L, and soluble C5b-9 was elevated. Renal biopsy showed mesangial expansion, double contours, pseudothrombotic eosinophilic deposits in capillary loops, immune deposits, subendothelial and mesangial electron-dense deposits, and partial foot process effacement. These findings supported bevacizumab-associated glomerular microangiopathy. He received amlodipine for blood pressure, furosemide for edema, and atorvastatin for dyslipidemia, with management aimed at controlling nephrotic syndrome and kidney injury. Pralatrexate plus anlotinib continued as anticancer therapy after discharge. At July 29, 2024 follow-up, he still had hypertension, renal dysfunction, and severe proteinuria, showing that the kidney complication persisted even after bevacizumab had been stopped.