1. Renal Tract Calculi Alex Papachristos

2. Overview Background Background Pathophysiology Pathophysiology Epidemiology Epidemiology Presentation Presentation Investigation Investigation Management Management

3. Background 1% of hospital admission are due to acute renal colic 1% of hospital admission are due to acute renal colic Excruciating pain > broken bones, childbirth, gunshot Excruciating pain > broken bones, childbirth, gunshot

4. Pathophysiology supersaturation of urine by stone- forming constituents (calcium, oxalate, uric acid) supersaturation of urine by stone- forming constituents (calcium, oxalate, uric acid) Crystals / foreign bodies act as nidi – ions from supersaturated urine can form microscopic crystalline structures Crystals / foreign bodies act as nidi – ions from supersaturated urine can form microscopic crystalline structures

5. Stone composition 80% calcium containing (oxalate/phosphate) 80% calcium containing (oxalate/phosphate) Struvite (10-15%) Struvite (10-15%) Uric acid (5-10%) Uric acid (5-10%) Rare – familial (homocysteinuria), Indinavir Rare – familial (homocysteinuria), Indinavir

6. Epidemiology Lifetime prevalence – 12% for men, and 7% for women (US data) Lifetime prevalence – 12% for men, and 7% for women (US data) Rates are doubled if there is a FMH Rates are doubled if there is a FMH Peak incidence 35-45 years Peak incidence 35-45 years Initial stone attack after 50yrs uncommon Initial stone attack after 50yrs uncommon Male:Female ratio: 3:1 Male:Female ratio: 3:1 More common in Anglo-Saxons and Asians than native Americans, African More common in Anglo-Saxons and Asians than native Americans, African

7. Risk factors Low fluid intake Low fluid intake Western diet Western diet Supplemental calcium Supplemental calcium

8. Presentation Symptoms Symptoms –Pain –Nausea and Vomiting –Haematuria –Fever

9. Diagnosis Xray KUB Xray KUB CT KUB (non-contrast) CT KUB (non-contrast) Xray IVP Xray IVP

17. Management Initial Mx: Initial Mx: –Pain relief –Hydration –Basic bloods –Is there an indication for urgent intervention?

18. Indications for Intervention Infected obstructed kidney Infected obstructed kidney Impaired renal function due to obstruction Impaired renal function due to obstruction Solitary kidney Solitary kidney Uncontrolled pain Uncontrolled pain

19. Emergency Intervention Immediate aim is relieving obstruction Immediate aim is relieving obstruction –Double-J stent insertion –Ureteroscopic stone extraction (if no active infection) –Nephrostomy

20. Definitive managment

21. Will the stone pass? Size of stone is inversely proportional to its chance of passing spontaneously Size of stone is inversely proportional to its chance of passing spontaneously Rule of thumb: Rule of thumb: –1mm stone - 90% chance of passing –4mm stone - 60% chance –8mm stone - 20% chance

22. Watchful Waiting Stones that have not passed in two month are unlikely to do so Stones that have not passed in two month are unlikely to do so Permanent damage to kidney occurs after ~4 weeks Permanent damage to kidney occurs after ~4 weeks Can try an alpha-1 blocker - smooth muscle relaxant Can try an alpha-1 blocker - smooth muscle relaxant

23. Treatment options Watchful waiting Watchful waiting ESWL ESWL Ureteroscopic stone extraction Ureteroscopic stone extraction Percutaneous nephrolithotomy Percutaneous nephrolithotomy

24. Long-term Management High fluid intake is most important High fluid intake is most important Stone analysis - alkalanise urine if uric acid stone Stone analysis - alkalanise urine if uric acid stone Low salt, high fibre diet Low salt, high fibre diet

25. Bladder Calculi Most common in men aged > 50 with bladder outlet obstruction Most common in men aged > 50 with bladder outlet obstruction –Stasis of urine leads to stone formation