Nephrolithiasis — Written Clinical Reasoning

SAQ — Recurrent stone former with Crohn disease (20 marks, 30 minutes)

Prompt: Work through the diagnosis and pathophysiology, the metabolic evaluation, an integrated prevention plan, acute and surgical management, and long-term follow-up for this patient. Justify each decision with reference to evidence. ^[1]

Case vignette: A 48-year-old man with ileocolonic Crohn disease and a prior terminal ileal resection (4 to 6 loose stools daily) presents with his fourth calcium oxalate stone in six years. 24-hour urine: volume 1.2 L/day, calcium 5.2 mmol/day, oxalate 0.9 mmol/day, citrate 1.2 mmol/day, sodium 180 mmol/day. Serum calcium and PTH normal; bicarbonate 20, potassium 3.4. He eats only 500 mg calcium daily and drinks 1.5 L fluid daily. ^[1]