The kidney acts as a filter for blood, removing waste products from the body and helping regulate the levels of chemicals important for body function. The urine drains from the kidney into the bladder through a narrow tube called the ureter. When the bladder fills and there is an urge to urinate, the bladder empties through the urethra, a much wider tube than the urethra.
Kidney stones can form when the urine contains too much of certain substances. These substances can create small crystals that become stones. Kidney stones may not produce symptoms until they begin to move down the ureter, causing pain. The pain is usually severe and often starts in the flank region, then moves down to the groin.
Kidney stones are small, solid masses that form when salts or minerals normally found in urine become solid crystals (crystallise) inside the kidney. In most cases, the crystals are too tiny to be noticed, and pass harmlessly out of your body. However, they can build up inside your kidney and form much larger stones.
The formation of stones in the kidneys or urinary tract is not an uncommon disorder. The stones are formed from the chemicals usually found in the urine such as uric acid, phosphorus, calcium, and oxalic acid. They may vary in consistency from grit, sand, and gravel-like obstructions the size of a bird’s egg.
Symptoms of Kidney Stones
Symptoms of kidney stones (aka, renal calculi) vary from person to person, but most people experience severe pain. Kidney stone pain is characterized by its severity. The excruciating pain is usually centralized in the back or sides and sometimes moves as the stone moves. During an attack, many sufferers experience nausea and vomiting. They may discover blood in their urine. About eighty percent of stones are small enough to be passed without symptoms and there are some people that have kidney stones but never experience pain.
Kidney stones form when there is a decrease in urine volume or an excess of stone-forming substances in the urine. The most common type of kidney stone contains calcium in combination with either oxalate or phosphate. Other chemical compounds that can form stones in the urinary tract include uric acid and the amino acid cystine.
Most kidney stones pass out of the body without any intervention by a physician. Stones that cause lasting symptoms or other complications may be treated by various techniques, most of which do not involve major surgery. Also, research advances have led to a better understanding of the many factors that promote stone formation and thus better treatments for preventing stones.
The size of the stone does not dictate the size of the pain. A small jagged stone can produce more distressing symptoms than a larger smooth stone. A great deal of the pain experienced while passing a stone is not the result of the stone ripping through the urinary tract (although it certainly can feel that way). Much pain is due to muscle contractions as the ureter attempts to force the stone into the bladder. If the sufferer experiences a fever along with these other symptoms, he or she may have an infection.