INS and chronic kidney disease: Patient 1: a 78-year-old woman with a body mass index (BMI) of 26.3 kg/m2 on metformin and insulin therapy with chronic kidney disease (CKD) stage IIIa due to traumatic unilateral nephrectomy was admitted to the emergency department (ED) with nausea, vomiting, acute on chronic renal failure (creatinine 796.5 μmol/l, blood urea nitrogen 28.4 mmol/l) and metabolic acidosis with Kussmaul breathing (pH = 6.89, HCO3 = 5 mmol/l, pCO2 = 17.3 mm Hg or 2.3 kPa).