Urinary Stones

Urinary stones are formed in the urinary tract (typically in the ureters and renal pelvices) from some waste products that are eliminated by urine. The stones may be very painful and cause further complications, some of them very serious.


Just like in the article about urinary infections, I should simply describe the urinary tract. Urinary tract consists of two kidneys filtering blood and producing urine. The urine flows into renal pelvices and through ureters into the urinary bladder. The connection between a ureter and urinary bladder is anatomically shaped to prevent a reflux of urine back into the ureters. The lower part of urinary bladder is equipped with a muscle sphincter. When relaxed, the sphincter allows the urine to flow into urethra and through urethra out of the body.


There are more types of urinary stones having different causes. The most common reason is chronic dehydration with inadequately low intake of fluids. Dehydration leads to low production of urine with a high concentration of crystal-forming substances (calcium, phosphate, uric acid and oxalate) and with improper pH (too high or too low). The stone formation may also be increased by bacterial urinary infections.


The disease manifests when a stone blocks the urinary tract. Such situation manifests as the so-called kidney colic with strong shocking sharp abdominal pain with intermittent character alternating with periods of calm. The pain is located on side of the affected ureter and it may spread towards the groin. The pain is caused by periodic contractions of the urinary tract muscles trying to remove the obstacle. The pain is usually accompanied with nausea and vomiting. Urinary stones may injure the urinary mucosa causing occurrence of blood in urine.


The complications can be very serious. If the obstruction persists for a longer time, it leads to failure of urine flow. The urine accumulates above the obstacle and this causes of locally increased pressure of the urine. This process can compress kidney tissue causing the so-called hydronephrosis and possibly even irreversible damage of kidney functions. Accumulated urine is also a good environment for bacteria and therefore it increases risk of urinary infections including the pyelonephritis.


Clinical symptoms and physical examination focused on patient's abdomen should be supported by abdominal X-ray or more precise abdominal ultrasound.


The best prevention is adequate fluid intake, which is very important for the elderly who often do not have the feeling of thirst. Some urological teas may also have positive effect by changing the pH of urine reducing formation of crystalline substances.


The pain may be treated by drugs causing muscle relaxation (antispasmodics) and adequate hydration. Some stones leave spontaneously; others must be removed by various urologic procedures. The working instruments are usually introduced through urethra and some stones may be crushed by a relatively painless external shock wave lithotripsy. When it is impossible to remove the stone in upper urinary tract, it is sometimes necessary to perform a temporary nephrostomy.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources