MRCP2-3996

MRCP2-3996

A 30-year-old man presents to your acute medical unit with right flank pain that has been constant for the past 2 weeks. Despite taking paracetamol tablets, the pain has not subsided. He denies experiencing dysuria and is generally in good health, although he is a smoker. He mentions that his sister recently passed away from a subarachnoid haemorrhage caused by a berry aneurysm.

Upon examination, the patient’s heart rate is elevated at 110 bpm, but all other observations are normal. A urine dipstick test reveals 2+ blood and nothing else. Blood tests show a sodium level of 141 mmol/l, potassium level of 4.6 mmol/l, urea level of 3.6 mmol/l, creatinine level of 84 mol/l, and CRP level of 34 mg/l. His FBC is normal.

What is the most likely diagnosis?