Presence of calculi or stones in the urinary tract, anywhere from the kidney to the urethra is termed as Urolithiasis. It is a common condition worldwide and the incidence is on the rise. In India, it is estimated that 12% of the population harbour stones in their urinary tract and nowadays more women are being diagnosed with renal stones. In general, men are more likely to have kidney stones than women but recent statistics reveal that this gender gap is narrowing.
A combination of various risk factors predisposes a person to develop stones. Endogenous risk factors include Age (40-60), gender (men>women), and heredity. Exogenous risk factors are more important. Climatic conditions wherein people living in hot and dry conditions are more likely to develop stones. Dietary factors play a vital role. Low water intake is the common denominator as far as dietary factors are concerned. Consumption of high salt and animal protein have been proven to cause urinary stones. Obesity too has been linked with stone formation in some studies. Calcium is the commonest constituent of urinary stones with calcium oxalate being the commonest type of stone. Uric acid stones, infection-related stones and phosphate stones also occur.
Signs And Symptoms Of The Urinary Stones:
As seen earlier stones can form anywhere in the urinary tract from the kidneys to the urethra. Stones inside the kidney usually are silent that is the patient may not have any symptom attributable to the stone unless the stone is very big. These stones are usually discovered during ultrasound scans done for some other purpose or during routine health check-ups. When a stone residing in the kidney detaches and drops into the tube connecting the kidney to the bladder called as the ureter, the person develops sudden and severe pain along the flank that can radiate to the genitalia. This pain is called as Renal Colic. The person can also have blood in the urine termed as hematuria. The reason for the pain is that the stone blocks the flow of urine on that side. The condition becomes serious when it is associated with infection evidenced by the development of fever with chills. Stones in the bladder usually causes pain, blood in urine and difficulty in passing urine.
Diagnosis Of Stones:
The most useful imaging test in such a situation will either be an Ultrasound scan or a CT scan. Ultrasound scans are cheaper, carry no risk of radiation but are less accurate. On the other hand, CT scans are expensive, carry a very small risk of radiation but are extremely accurate in finding location, number, size and stone density.
The doctor may also order additional urine and blood tests to see the presence of infection and to check the renal function. In certain situations, special tests like 24-hour urine analysis and parathormone level may be done to rule out any potential metabolic abnormality that may be causing the formation of stones.
Whenever a person is admitted to the hospital with severe flank pain, the treating doctor usually gives a pain-killer injection which alleviates the pain in the majority of the situations. The person is then sent for scan either an ultrasound scan or a CT scan. Once the scan confirms the presence of stone, then the type of management depends on the location and size of the stone. As mentioned earlier, stones that are stuck in the ureter are the ones which usually results in renal colic. Stones up to certain size have a good chance of coming out by themselves with the help of medicines and adequate water intake. But as the size of stone increases, the likelihood of the stone coming out by itself decreases in which case the patient may require some kind of surgical intervention to remove the stone. Another situation which may warrant immediate removal of the stone is the presence of infection evidenced by fever with chills.
Methods Of Stone Removal:
Various surgical techniques or methods are available to remove the stones. Once upon a time, stone removal required open surgical techniques leaving behind a big scar and necessitating a long recovery time. But now-a-days almost all the stones are removed by less-invasive endoscopic techniques with no scar and short recovery time. The choice of the technique again depends on the size and location of the stone. There is no “one size fits all” approach.
ESWL (Extra-Corporeal Shock-wave Lithotripsy):
Ultrasonic sound waves are produced by a machine which is then focussed onto the stone. This method is suitable for stones present inside the kidney with the size less than 1.5 cm. The advantages of this method is that it is cheaper, non-invasive and can be done as an outpatient procedure. The disadvantage being incomplete fragmentation of the stone resulting in multiple sessions and incomplete clearance of the fragments and obstruction & infection.
URS (Uretero-Renoscopy) :
It is the commonest procedure performed. It is used for stones that are lodged in the ureter. It involves the passage of an endoscope either rigid or flexible with a camera through the natural urinary passage from below into the ureter. The stones are then fragmented with a laser and the fragments are retrieved. It is a less-invasive method usually requiring a short hospital stay.
PCNL (PerCutaneous NephroLithotomy):
This method is used for stones inside the kidney which are larger in size (>2cm). It involves the passage of an endoscope directly into the kidney through the skin of the back. The stone is then fragmented with a laser and the fragments are retrieved. The advantage of this method is a faster and complete clearance of the stone.
Laparoscopy too can be used to remove stones of a certain size and at some locations.
Follow-Up And Prevention:
Studies have shown that there is a 50% chance of stone recurrence within 5 years of the first episode. Hence follow-up and preventive measures are important. Any patient treated for the stone disease should have an ultrasound scan at least once in a year to detect formation of new stones. The patients are also advised to modify their diet which includes a high fluid intake around 3 litres/day, consumption of less salt and animal protein. By following proper dietary lifestyle changes and few medications recurrence of stones can significantly be reduced.