MRCP2-4076
A 55 year-old man presents with right flank pain. The pain is 9/10 on the pain scale, and does not radiate anywhere. He has also suffered from thirst, polyuria and fatigue, which he has put down to stress from being off work due to a history of chronic lumbar back pain. He has a smoking history of 10 pack years and drinks on average a couple of pints of beer at the weekends. He has no relevant family history.
On examination, he has tenderness in the right flank and lower back and his blood pressure is 149/92 mmHg. Blood tests reveal Hb 9.9 g/dL, platelets 284 * 109/l, WBC 10.5 * 109/l, mean corpuscular volume 86 fl, Na+ 129 mmol/l, K+ 3.9 mmol/l, urea 16.3 mmol/l, creatinine 410 µmol/l, calcium 2.19 mmol/l, phosphate 1.79 mmol/l, and uric acid 0.40 mmol/l.
Urinalysis reveals protein ++, leucocytes +. Microscopy reveals renal papillary cells and casts. No organisms are identified. A plain abdominal x-ray is negative for calculi and calcification. Intravenous urogram reveals clubbed calyces and ring signs.
What is the most likely diagnosis?