Kidney stones most commonly occur in the upper urinary tract. The composition of these stones may differ depending on metabolic alterations, presence of infections, geography, etc. They may vary in size (gravel to staghorn calculi). Most are radio opaque. Some may also result from inborn errors in metabolism like gout, cystinuria, primary hyperoxaluria etc.

Metabolic alterations cause changes in the components of urine (fluids, acids and minerals). This imbalance causes more crystal forming substances like calcium etc., than the fluid can dilute, forming stones. Stones can also form when the urine is short of substances that keep the crystals from sticking and forming stones.

Most stones contain crystals of more than one type. Depending on the crystals that make up the bulk of the stone, the cause is identified.

Large stones can be asymptomatic when they are immobile but small stones arising from the kidney pass into the ureters causing severe colicky pain.

Mucosal trauma (from friction) or obstruction can give rise to super imposed infection. Although some stones may be asymptomatic, most stones cause pain at some point.

Although there are several different types of kidney stones, a majority of them contain calcium. The kidney stone or renal calculus may go unnoticed for several years and only cause problems as it begins to descend from the kidney to the bladder through a tube called the ureter. When the kidney stone blocks the urine from its normal transit, severe pain ensues. The pain is usually described as “the worst pain I have ever felt,” starts in the back and frequently travels around the stomach to the groin region. Other symptoms of kidney stones may include blood in the urine or frequent urination.

Symptoms
The pain begins as an ache in the back and side (the flank). Then, it becomes constant and severe as the urinary system tries to rid itself of the stone. Sometimes, there is burning during urination, blood in the urine, or a frequent urge to urinate. Nausea and vomiting may occur, and the lower abdomen or flank may be painful, if touched.

Back pain from kidney stones can be on the right or left side of the back and side.
Kidney stones can be managed by a variety of treatments, such as:

• Watchful waiting where liberal amounts of pain medication are given.
• Extracorporeal shock wave lithotripsy (ESWL) where a patient has the stone blasted from outside the body, requiring very little anesthesia.
• Invasive methods which include passing small telescopes up the ureter to engage the stone, break it apart, and remove it to open surgical removal.

Your best means of avoiding kidney stones is to increase your water intake, especially during the hot summer months.