BENGALURU : Urinary stone disease is a common problem, which affects up to 12 per cent of the population. Unless treated properly, with countermeasures, this can even lead to renal failure.
Formation of kidney stones
Kidney stones can form when substances in the urine – such as calcium, oxalate, etc – become highly concentrated. Diet is one factor that can inhibit kidney stone formation. Some foods may promote stone formation. Other factors include genes, environment, body weight, and fluid intake.
Types of kidney stones
There are four major types of kidney stones. Calcium stones are the most common. Calcium oxalate stones are more common and caused by high calcium and oxalate excretion. Calcium phosphate stones are caused by the combination of high urine calcium and alkaline urine. Uric acid stones form when the urine is persistently acidic. A diet rich in purines – substances found in animal protein – may increase uric acid which can settle and form a stone.
Struvite stones result from kidney infections. Eliminating infected stones can prevent more stones.
Cystine stones result from a genetic disorder that causes cystine to leak through the kidneys and into the urine, forming crystals that accumulate into stones. Other less common stones, include xanthine and drug-related stones.
Prevention
An important step in preventing stones is to understand what is causing them. Information helps suggest diet changes. People can prevent stones by making changes in fluid intake. It is recommended that a person drink 2.5 - 3 litres of fluid a day.
People who have had a kidney stone should drink enough fluids to produce at least 1.5 litres of urine a day. Meats and other animal proteins break down into uric acid.
People who form uric acid stones should limit their meat consumption to six ounces each day.
Medical management
This is possible only in small stones usually less than 6mm in size. The medicines dilate the ureter and promote stone expulsion.
Surgical management
Stones in the ureter up to 2 cm are usually treated by Ureteroscopy (URS). A small scope is placed through the natural orifice into the ureter and the stone is broken with a laser. A stent is placed for three weeks. It’s a single-day procedure under anaesthesia.
Kidney stones
Patients who get treated for kidney stones by whatever means have almost a 50 per cent chance of recurrence of stones. Hence they need to be on long-term medication for stone prevention, follow preventive methods, assess periodically with a scan and adequate follow up with a urologist.
Tests
Blood tests to check infection, uric acid and renal function, is the primary detection method. A basic ultrasound of the abdomen and X-ray also help. PLAIN CT KUB is the ideal choice for confirmation.
Symptoms
Classic presentation of a renal stone is acute flank pain radiating to the groin or scrotum. As the stone descends in the ureter, pain may localise to the abdomen. Renal and ureteral colic are considered as the most severe pain. As the stone approaches the urinary bladder, lower abdominal pain, urinary urgency, frequency, and dysuria are common. The presence of blood in urine, nausea and vomiting can also be present.
(The writer is senior consultant urologist, endourologist and transplant surgeon at VPS Lakeshore, Cochin)