EN 
ES Doctor Juan Pablo Mejia - Urologist, assistant physician Department of Urology of the Hospital de la Plaza de la Salud.
Source: Newspaper Today
Urinary stones are also known as kidney stones and can affect the kidneys as well as the tubes that expel urine from them.
This situation represents the third cause of consultation in urology, occurring more frequently in men than in women, a risk that is equalized when women reach menopause, perhaps due to the loss of the protective factor that estrogens exert on them.
The kidneys are specialized glands that are located -in relation to the lumbar spine- in a place in the abdominal cavity called the retroperitoneum. They receive abundant blood supply and are responsible for multiple functions, among which are the filtration of the blood, the production of enzymes and hormones that serve to regulate blood pressure and the production of blood cells. These substances are known as renin and erythropoietin, successively vitamin D production and urine production.
Through the production of urine, the kidneys are responsible for eliminating waste substances from the metabolism, as well as water and electrolytes.
Among these substances we find urea, creatinine, sodium, calcium, potassium, oxalates, etc. Water is known as the universal solvent, therefore, it is responsible for diluting the substances found in our body, it helps and is part of metabolic reactions, it is the most abundant component of the body and represents 70 % of body weight .
There are several theories that explain the formation of stones, but we can summarize it in urinary stasis, decrease in solvent (water), increase in solutes and / or decrease in protective factors that prevent the aggregation of salts in urine such as citrate and magnesium. These last two substances are very important that prevent the 'aggregation' of calcium crystals.
Urinary stones are salts that have a mixed or heterogeneous composition. In 85 % of the cases they are made of calcium in the form of calcium oxalate, calcium phosphate or calcium carbonate, so we have to take into account that calcium is not the only element that constitutes the stones and, therefore reason, it is not the only element that we are going to quantify when evaluating the patient.
There are stones of infectious origin, produced by bacteria that through their metabolism are capable of creating salts that precipitate in the urine. There are also genetic diseases and metabolic disturbances that cause certain substances to reach abnormal concentrations in the urine and precipitate, forming crystals, and subsequently appear stones, such is the case of cystinuria and hyperuricosuria, which is characterized (the latter) by increased the concentration of uric acid in the urine, which leads to the precipitation of uric acid salts, forming hard stones difficult to fragment, of an amber coloration.
The mechanical effect of the obstruction produced by kidney stones in the duct system causes an increase in intrarenal pressure, which can lead to progressive and irreversible kidney damage.
