Renal failure after cardiac surgery

A 52 year old non-smoking black man presented with a two week history of dysuria, malaise, fever, and rigors. In the past he had had recurrent urinary tract infections requiring antibiotic treatment.

On clinical examination he had a temperature of 38.9°C, his pulse rate was 70 beats/min, and blood pressure was 125/70 mm Hg. A pansystolic murmur was auscultated, which was loudest at the apex beat and radiated to the left axilla. Urine dipstick was positive for protein and blood. Laboratory investigations showed a haemoglobin concentration of 9.7 g/dl (normocytic), white cell count of 12.2 ¥ 109/l (neutrophil count 8.8 ¥ 109/l), C reactive protein of 106 mg/l, erythrocyte sedimentation rate of 130 mm in the first hour, raised corrected calcium (2.73 mmol/l), and a total protein count of 113 g/l. Renal …