The kidneys are two bean-shaped organs, approximately 12 cm. long, 6 cm. wide, and 3 cm. thick located at the back of the abdomen on each side of the spinal cord next to the upper lumbar vertebrae. The function of the kidneys is to regulate and filter the blood's content of salts and waste products from the metabolism of the body's cells. In this way, the kidneys also help regulate the acidity, the PH value, of the blood.
The kidneys excrete the substances which the body does not need, in the form of urine. Urine consists of 95% water - the rest is various organic and inorganic substances. The central part of the kidney is a hole called the renal pelvis. Here, the urine is collected from approximately 1.3 million small filtering units called nephrons after which it is led down the right or left ureter to the urinary bladder and from there it leaves the body through the urethra.
Various sufferings with metabolic defects, increased activity of the adrenal glands and parathyroid glands, long-lasting treatment with cortisone preparations, long-lasting confinement to bed, urinary tract infection, nutritional deficiencies, and poor dietary- and drinking habits all contribute to altering the acidity of the urine and its content of mineral salts. Under certain conditions where the urine is saturated with these salts, kidney stones are formed. For this reason, the composition of kidney stones varies. An obvious cause for the formation of kidney stones is, however, not always easy to find. In these cases, you should look for disregarded dietary factors.
The size of kidney stones also varies. The smallest stones are called renal calculus. They are usually flushed out with the urine.
Stones with diametres of about 5 - 6 mm. can at best pass through the ureter to the bladder where they are removed with the urine but they can, of course, also become so big that they will have to be removed surgically or with a calculus crusher. This, of course, takes place in a hospital. There have been examples of stones that have filled out the whole renal pelvis. Kidney stones is a serious problem because it can stop the flow of urine and thereby cause extension and inflammation of the renal pelvis. Moreover, the pressure of the urine can gradually destroy the renal tissue. Kidney stones can also scratch the cellular walls and make blood appear in the urine. Often, however, the amount of blood is too small to be seen with the naked eye. The risk of having urinary tract inflammation is generally high in case of kidney stones.
Calcium stones
The majority of all kidney stones consists of calcium salts (calcium oxalate and calcium phosphate). This type of stone is very hard. It is rarely bigger than a couple of centimetres.
Organic stones
About 5 - 10% consist of salts of uric acid or the amino acid cystine. These stones do not contain calcium and this makes it difficult to discover them.
Infection stones
About 10 - 15% of the kidney stones consist of magnesium ammonium phosphate. They are also called infection stones because these salts are only precipitated in relation to a bacterial infection in the urinary passages. The precipitation of crystals which can grow into kidney stones is promoted by the fact that they can cling to the bacteria.
Symptoms
Not all kidney stones cause symptoms but are simply flushed out with the urine when possible. When kidney stones do cause problems, however, they are often violent. The pains come in attacks and are also called colic pains. They typically last for several minutes at a time and cause violent, painful shooting pains followed by nausea and vomiting. Usually, the pains are detected in the back. From there, they can radiate into various directions according to the location of the stone. The pains will move according to the stone descending through the ureter. It might take a couple of hours for a kidney stone to move from the renal pelvis to the urinary bladder and as soon as the stone falls down into the bladder, the pains stop. Some stones are formed in the bladder and are strictly speaking not kidney stones but bladder stones.
