Pathophysiology                                                                            Stones can form anywhere in the urinary tract, but common sites are: vesicoureteric junction (60%), ureteropelvic junction in kidney, and sacroiliac joint (where ureter crosses iliac vessels). 80% are calcium stones, which also contain oxalate (commonest), phosphate, or both. Other stone types include struvite (magnesium ammonium phosphate) – forming staghorn stones – and urate. Signs and symptoms Renal colic: Sudden onset of severe, intermittent pain, due to peristalsis against the obstruction. Ureteric stone pain radiates from loin to groin. Midureteric stones can mimic appendicitis or diverticulitis. Patient writhing, trying to get comfortable, unlike peritonitis where they are still. Genera...