KOCHI: Urinary stone disease is a very common problem nowadays. As per estimates, it affects up to 12 per cent of the population during their lifetime. In India, the occurrence of urinary stones has significantly increased over the years. Unless treated properly, with adequate countermeasures to prevent further stones, this can be a continuous problem and even lead to renal failure.
Formation of kidney stones
Kidney stones can form when substances in the urine — such as calcium, oxalate, phosphorus, uric acid, etc — become highly concentrated. Diet is one of several factors that can inhibit kidney stone formation. Certain foods may promote stone formation in people who are susceptible. Other factors that affect kidney stone formation 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 ones and they occur in two major forms: calcium oxalate and calcium phosphate. Calcium oxalate stones are more common and may be caused by high calcium and high oxalate excretion. Calcium phosphate stones are caused by the combination of high urine calcium and alkaline urine, meaning the urine has a high pH. Uric acid stones form when the urine is persistently acidic. A diet rich in purines — substances found in animal protein such as meats, fish, and shellfish — may increase uric acid in urine. If uric acid becomes concentrated in the urine, it can settle and form a stone by itself or along with calcium.
Struvite stones result from kidney infections. The most common pathogen is Proteus mirabilis. Eliminating infected stones from the urinary tract and staying infection-free can prevent more struvite stones.
Cystine stones result from a genetic disorder that causes cystine to leak through the kidneys and into the urine, forming crystals that tend to accumulate into stones. There are other less common stones, including xanthine and drug-related stones as well.
Prevention
An important step in preventing kidney stones is to understand what is causing them. This information helps suggest diet changes to prevent future occurrences. Most notably, drinking enough fluids helps prevent all kinds of kidney stones by keeping urine diluted and flushing away materials that might form stones.
People can help prevent kidney stones by making changes in fluid intake. It is recommended that a person drink 2.5 - 3 litres of fluid a day. Depending on the type of kidney stone, changes in consumption of sodium, animal protein, calcium, and oxalate.
People with cystine stones may need to drink even more water. Other fluids may also help prevent kidney stones, such as citrus drinks. People who have had a kidney stone should drink enough water and other fluids to produce at least 1.5 litres of urine a day. The risk of kidney stones increases with increased daily sodium consumption. The US recommended dietary allowance (RDA) of sodium is 2,300mg. Meats and other animal proteins —such as eggs and fish — contain purines, which break down into uric acid in the urine.
Foods especially rich in purines include organ meats, such as liver. People who form uric acid stones should limit their meat consumption to 6 ounces each day. Animal protein may also raise the risk of calcium stones by increasing the excretion of calcium. A diet chart is usually available with every urologist for stone prevention.
Medical management
This is possible only in small stones usually less than 6mm in size. The ureter, which transports urine from the kidney to the bladder, is only 5-6 mm diameter in size. The stones move from the kidney to the ureter and get blocked. First, try to flush out the stones with medicines. 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
The latest kidney stone management procedure is RIRS in which a flexible ureteroscope is placed via the natural orifice into the kidney and with the help of a laser, stones of any size up to 5cm, multiple or single, can be fragmented. Then, a stent is placed. It’s a single-day procedure.
Another procedure is PCNL — for very large kidney stones where a small 1cm incision is made on the abdomen side through which instruments are placed to reach the kidney stone under guidance. The stones are completely broken and the fragments are removed through this small incision and we can achieve complete clearance of the stones.
3D Laparoscopy (keyhole) – This is keyhole surgery for very large and multiple stones involving the whole kidney. Here the kidney is bivalved and opened up. All the stones are removed completely.
ESWL- Small stones above 6mm up to 1.5 cm can be broken with ESWL(shock wave) lithotripsy. Here the stone is focused with a shockwave under ultrasound guidance and broken. The stone fragments pass down naturally via the ureter and are expelled with the urine. However, the clearance rate of the stones is less with this method. Patients may require multiple sittings and hard stones might not break.
Patients who get treated for kidney stones by whatever means have almost a 50% 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
The classic presentation of a renal stone is acute, colicky flank pain radiating to the groin or scrotum. As the stone descends in the ureter, pain may localise to the abdomen overlying the stone. Renal and ureteral colic are often considered among the most severe pain experienced by patients. 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. Features of recurrent urinary infections with fever can also be another symptom. Some large stones fixed in the kidneys may not cause any of these symptoms and are diagnosed incidentally on diagnostic evaluation.
Mind and body
Got health concerns you want to share with a doctor? Are you looking for credible answers regarding symptoms, medicines or lifestyle disorders? Write to us on cityexpresskoc@newindianexpress.com, and we will get healthcare professionals to answer them.
The writer is a senior consultant urologist, endourologist and transplant surgeon at VPS Lakeshore, Cochin