Mr Daniel Yao1, Elaine Cheng1, John Kelly1, Patricia Bastick2, Ivor Katz
1Department of Renal Medicine, St George Hospital, Kogarah, Australia, 2St George Oncology Associates, Kogarah, Australia
Biography:
Daniel Yao is a Resident Medical Officer at St George Hospital, with an interest in renal medicine.
Elaine Cheng is a Renal Advanced Trainee at St George Hospital.
Background:
Cancer in Australia is increasing and the incidence of acute kidney injury (AKI) in patients with cancer is around 18% in the first year. Nearly 80% of cancer patients receive drugs that can harm the kidneys, leading to AKI, delaying treatment, increasing hospitalisation, and mortality. Pre-existing chronic kidney disease (CKD) aggravates risk of nephrotoxicity as do existing risk factors. Both new and existing cancer therapies can interact to enhance AKI.
Case Report:
A 79-year-old female with a past medical history of metastatic breast cancer and type 2 diabetes presented with lethargy and confusion. This followed a fixation of a distal radius fracture. She recently started anastrozole (aromatase inhibitor) and then ribociclib (cyclin-dependent kinase 4/6 inhibitor) for her ER/PR positive, HER2 negative progressive cancer. She was also on metformin. Bloods leading into her admission suggested AKI (Cr 145µmol). There was reduced oral intake pre- and post-surgery. Examination revealed hypovolaemia and hypoglycaemia (BGL 1.3mmol/L, ketones 3.4mmol/L). Lab findings included severe lactic acidosis (pH 6.84, lactate 25mmol/L, base excess -26.8mmol/L, bicarbonate 3.8mmol/L), and AKI (urea 16.1mmol/L; Cr 277µmol/L) and hyperkalaemia (K 5.7mmol/L); baseline creatinine 82µmol/L, eGFR 63mg/mmol. Medications were withheld. In ICU she had fluids and sodium bicarbonate; but needed dialysis for acidosis. She recovered and was well at discharge.
Conclusions:
Nephrotoxicity is a common complication of cancer treatments, with conventional chemotherapy, targeted and new therapies. This case demonstrated how ribociclib may have been a factor, as was her advanced age, concurrent use of metformin with dehydration, resulting in AKI and acidosis. Pre-existing decline in kidney function, should have been a warning. Recognising the complexity of cancer therapies, onconephrology is becoming a much-needed area of expertise.