Kidney Stones are also termed as Renal Calculi. (Nephrolithiasis) A kidney stone is a hard, crystalline material formed within the kidney or urinary tract.
Renal stone disease is common, with a worldwide prevalence of between 2 and 20%. Lifetime prevalence is nearly 10% in men and 5% in women. Approximately 50 percent of patients with previous urinary calculi have a recurrence within 10 years.
Dietary risk factors associated with increased stone risk:
Low fluid intake, High intake of animal protein, High dietary sodium, Excessive intake of refined sugars, Foods rich in oxalate, High intake of grapefruit juice, apple juice and soft cola drinks.
Family history of kidney stones (increase risk by three times)
History of hypertensio
Various other medical conditions.
A kidney stone is a small stone, usually made up of calcium crystals, that forms inside the part of the kidney where urine collects. The stone usually causes little problem until it falls into the ureter, the tube that drains the kidney into the bladder, and causes an obstruction, preventing urine from draining out of the kidney and often causing severe pain.
One of the roles of the kidney is to remove waste from the body by filtering blood and making urine. That urine flows from the kidney into the bladder through the ureter, a thin tube that connects the two. The bladder empties through the urethra, a tube much wider than the ureter.
A variety of minerals and chemicals are excreted in the urine and sometimes these combine to form the beginning of a stone. Over time, this can grow from an invisible speck of sand into a stone that can be an inch in diameter or larger.
There are different terms for kidney stones depending upon where they are located within the urinary tract.
t isn’t exactly clear what causes kidney stones to form in some people and not others. Usually it requires concentrated urine that allows minerals like calcium to come in close contact with each other. Changes in the acid-base balance (pH) of the urine, how concentrated it is, and the concentration of minerals and chemicals within the urine are all factors that can begin the formation of a stone.
Crystals can form the beginning of the stone and eventually grow large enough to cause problems. Concentrated urine often occurs during an episode of dehydration, setting the stage for the beginning of stone formation. The consequences of that stone, when it is large enough to cause an obstruction, may occur weeks, months, or years later.
· Western diet with increased intake of animal protein and carbohydrate is associated with increased urinary calcium, oxalate, phosphate and hypocitraturia compared with controls and thus represents a potent risk of stone formation. So patients should be advised to restrict this type of diet.
· Dietary intake of calcium should also be restricted. However it has been shown that calcium binds oxalate in the gut preventing its uptake, so low calcium intake will increase the amount of oxalate available for absorption creating an increased risk of oxalate crystallisation. So in mild hyperoxaluria, a high calcium diet is required, together with a diet avoiding oxalate-rich foods (e.g. tea and chocholate).
· A mega dose of vitamin C should be avoided.
· No excess stone risk has been shown related to dietary intake of sodium, sucrose or cola.
► Indomethacin 20 mg T.D.S. has been found to reduce calcium secretion. This may help in preventing further stone formation.