(renal calculi) - A common condition affecting adult men more commonly then adult women, although this difference is narrowing

They may be asymptomatic until they irritate or get stuck in the ureters. They might get stuck at any point along the ureters, but commonly at the vesico-ureteric junction.

Types of stones:

• Calcium based stones (60-80%)
  • Key R/F - Hypercalcaemia and a low urine output
  • 2 types: Calcium oxolate (most common) and calcium phosphate
• Struvite stones(10-15%)
  • Triple phosphate stones, produced by bacteria (infection)
  • Made of calcium, magnesium and ammonium
  • Staghorn calculus most likely to be due to struvite stones
• Uric acid stones (5-10%)
  • Form in acidic urine, more common in people with a diet rich in animal protein
  • Not visible on x-ray
• Cystine stones
  • Associated with cystinuria - An autosommal recessive disease
  • Causes recurrent kidney stones in younger patients

Risk factors:

• Dehydration
• Diet (particularly salt intake)
• White ancestry
• Male
• Obesity
• Crystalluria
• Recurrent UTIs (struvite stones)
• Anatomical abnormalities
• Previous episodes of nephrolithiasis