Kidney, ureteral and bladder stones

Calculosis (or lithiasis from the Greek “lithos” – stone) is one of the pathological conditions that most frequently affects the urinary tract. It involves the formation of aggregates of minerals and organic substances that, once deposited, appear as real pebbles inside the excretory cavities of the kidney. The main problem caused by kidney stones is that they can obstruct the passage of urine to the bladder. Such obstruction may affect almost the entire length of the urinary tract. We speak of renal stones when stones are identified in the kidneys, ureteral stones when stones from the kidney enter the ureter and bladder stones when stones are found in the bladder. Stones found in the bladder may have descended from the kidney or may have formed directly in the bladder, due to urinary stasis that occurs in some patients with benign prostatic hypertrophy. Although in the past bladder stones were the most frequent of the three types, today they are by far the least frequent, having given way to renal and ureteral lithiasis. Urinary stones is a very frequent event (and globally increasing) in the general population: it is estimated that it can affect up to 10-15% of adults taking into account differences in age, gender, ethnicity, latitude; it is known that men (peak incidence 30-69 years) are affected about three times more than women (peak incidence 50-79 years), although this difference is increasingly reducing. Other risk factors include Caucasian race, living in hot and arid regions, sedentary work, exposure to high temperatures, obesity, familial anamnesis, presence of kidney malformations, and poor water intake. The formation of kidney stones, therefore, does not occur in all subjects, but only in some people and at certain times, which is connected with the alteration of the balance in the amount of substances eliminated through the kidney in the urine and urinary volume inadequate to prevent these substances from sedimentation and aggregation forming stones. Queste alterazioni possono essere momentanee (circoscritte a particolari momenti della vita, influenzate dai fattori sopra elencati) o continue (alterazioni metaboliche). There are different types of calculi classified according to their chemical composition: the most frequent are calculi containing calcium (about 75% of the total), in particular those containing calcium oxalate (about 60% of the total). Among calcium-free stones the most frequent are those consisting of uric acid. Most stones form due to a combination of genetic and environmental factors.