Urinary calculi consist of aggregates of crystals containing small amounts of proteins and glycoprotein. Different types vary in frequency around the world, probably as a consequence of dietary and environmental factors, but genetic factors may also contribute
Dull ache in the loin is rarely due to renal disease but may be due to renal stone, renal tumour, acute pyelonephritis or obstruction of the renal pelvis. This is most commonly caused by a congenital abnormality of the pelvi-ureteric junction (PUJ, p. 508), where typically the pain is precipitated by a large fluid intake

Symptoms of kidney stones include:

• Colicky pain: "loin to groin". Often described as the "worst pain ever felt".
• Hematuria: due to damage to wall of ureter and/or urethra
• Dysuria: when passing stones (rare)
• Oliguria: obstruction of bladder or urethra by stone, or extremely rarely, simultaneous obstruction of both ureters by a stone.
• Nausea/vomiting.