How do kidney stones form?

A kidney stone is solid deposit that is made from chemicals in the urine.

Urine has various wastes dissolved in it. Crystals begin to form when there is much more waste than liquid.

The chemicals which contribute to forming kidney stones are calcium, oxalate, urate, cystine, xanthine, and phosphate.

After it is formed, the stone may stay in the kidney or travel down the urinary tract into the ureter. Kidney stones can affect any part of one's urinary tract -- from kidneys to bladder.

Sometimes, tiny stones move out of the body, with urine, without causing too much pain.

But stones that don't move may cause a build-up of urine in the kidney, ureter, the bladder, or the urethra. This is what causes the pain.

Calcium oxalate, uric acid, and struvite are the main types of kidney stones.

Calcium oxalate is the most common type. It is created when calcium combines with oxalate in the urine. Inadequate calcium and fluid intake along with other conditions may contribute in its formation.

Uric acid is another common type. Too much intake of foods containing high amounts of purines, like organ meats or shellfish, may cause this.

Struvite stones are less common and are usually caused by infections in the upper urinary tract.

Poor diet, excess body weight, some medical conditions, and certain supplements and medications can also be among the causes of kidney stones. Sometimes they can run in the family.

Symptoms of kidney stones could be among the following:

-- Severe pain on either side of the lower back

-- More vague pain or stomach ache that doesn't go away

-- Blood in urine

-- Nausea or vomiting

-- Fever and chills

-- Urine that smells bad or looks cloudy

Doctors usually try to let the stone pass without surgery. They prescribe drinking a lot of fluid. Medications also help.

However, if the stones are too large or block the flow of urine, or if there is a sign of infection, it is removed with surgery.