Small kidney stones often pass unnoticed with urine. Larger kidney stones, however, can become lodged in narrow passages and block them. This leads to unbearable, cramping pain. No one who has suffered from renal colic wants to repeat the experience. In the summertime, the number of complaints with kidney stones increases dramatically – due to heat, increased sweating and insufficient drinking. Stones in the kidney and urinary tract are among the most common urological diseases. They are caused by salts normally dissolved in urine precipitating, depositing as fine crystals and clumping together to form larger structures.
Formation and causes of kidney stones
These “concretions” form mainly in the renal pelvis and the draining urinary tract, and less frequently in the kidney itself. In 80 percent of cases, they consist of calcium salts, calcium compounds that are easily visible in normal X-rays. Less common components are uric acid, cystine and xanthine.
Which substances and how the stone is composed depends on several factors, for example the acidity of the urine. Urinary stones can occur singly or in multiples, be very small (urinary gravel) or so large that they fill the entire renal pelvis, for example.
Kidney stones: Who is affected?
About four percent of the population in Germany have kidney stones.
Men are more frequently affected, and the tendency to them can be inherited. The development is favored by a disturbed urine flow, inflammation of the kidney and urinary tract and certain metabolic disorders (for example, hyperparathyroidism or gout).
Rapid weight loss, medications, and foods high in purines or oxalates, such as offal, spinach, and mushrooms, can also increase the risk of kidney stone formation in people at risk, especially if they also do not drink enough or sweat heavily.
Symptoms of kidney stones often go unnoticed
Not everyone who develops urinary stones feels them. Especially in the beginning, they are usually so small that they are flushed out during urination and thus go unnoticed. It is not uncommon for them to be detected by chance during an ultrasound examination. Some of those affected with chronic stone disease (nephrolithiasis) complain of recurring dull or pulling pain in the area of the flank.
Acute symptoms usually occur when a stone becomes lodged in the ureter. The cramping pain in the kidney bed is caused by the duct’s attempt to propel the kidney stone by alternately contracting and relaxing. These severe “renal colics” in the flank may radiate down the side into the lower abdomen and pubic region and are often accompanied by nausea and vomiting. Increased urination and discomfort during urination may also occur.
This kidney pain is felt to be labor-like and exceptionally severe, and sufferers are often restless and constantly moving. If a kidney stone completely obstructs the duct, urine can back up into the kidney and cause inflammation and infection, even life-threatening blood poisoning. Then the pain caused by kidney stones is accompanied by fever and chills.
