The human body contains two marvellous organs “the kidneys” to continuous filter
blood and get rid of waste and harmful products from the body. The kidneys are drained by
separate ureters into urinary bladder, which stores urine and empties at appropriate time. This
wonderful system is afflicted by multiple diseases, of which, stones are one of the common
On an average, lifetime prevalence of stone disease ranges from 1% to 15%. Relatively rare below 20 years of age, it is two to three times more common in men than in women. High prevalence is seen in hot, arid and dry climates like Rajasthan. Seasonal variation is seen with highest incidence in summer months. Risk also increases with body weight.
Three-fourth of all stones contains calcium, which makes it visible in the x-rays. Calcium oxalate is the predominant stone variant (60%). Non-calcium stones are like struvite
(infection stone) and uric acid stone. Uric acid stone is not visible in plain x-ray, but can be visualised in CT scan.
How can we suspect stone disease?
Stones most commonly present as excruciating pain, starting from flank region and
going down to groin or genitalia. The patient may feel nauseated or even vomit. The sufferer
fails to get any relief, as he tosses around in the bed. This may be associated with burning
sensation when attempting to void, frequent voiding with little amount of urine, occasional
blood in urine. Any episode of fever with chills heralds dangerous sign of infection.
Occasionally, the stones my silently damage the kidney. Sometimes, the stone may
block the drainage from the kidney, leading to hydronephrosis (swelling in the kidney) and in
extreme case, complete loss of kidney mass.
How is the diagnosis of stone disease made?
Suspicious history or sometimes non-specific abdominal pain leads to investigation with detection of stones. Stones more than few mm size can be picked up by ultrasound and X-rays. Both these techniques have their own technical limitations with chances of missing the stone. Plain CT of abdomen is up to 98% accurate in detecting even the smallest of stones, including those not seen on X-rays. The patient needs specialized radiological tests like IVP or CT-IVP for proper evaluation before any surgical intervention.
When to get the stones treated?
Although the stones are fairly common, a lot of smaller crystals and stones pass uneventfully into urine. However, as the size of the stone increases or the distance from the
urinary bladder increases, the probability of spontaneous clearance of stone decreases. Small renal stones lying in the periphery of kidney can be safely observed with periodic
sonographic examination. However, some stones cannot be managed by observation or any medication and need surgery for removal
- Small sized stones blocking the urine outflow from the kidneys
- Large sized (staghorn) stones in kidneys
- Stones in upper ureter causing pain
- Stones of >5 mm size in ureter, causing pain
- Bladder stones >1 cm size
- Stone in single kidney (whether congenital or opposite one removed)
- Infection stone
- Recurrent UTI
- Stones in persons working as pilots or in army
What are the different modalities of stone treatment?
Small stones (< 6 mm) lying in lower half of ureter can be given a trial of medicine, involving antibiotics, painkillers and medicines to relax the ureter. Persistence of pain, stone remaining at the same place for > 2 weeks or development of fever with chills warrants immediate surgical intervention. Any stone obstructing the kidney/ ureter for > four weeks can cause permanent damage to the kidney.
This is a non-invasive treatment wherein, stones are broken by shock waves generated by the machine. The patient lies on the table and focussed shock waves are targeted on the stone.
The stone is fragmented into small pieces, and are gradually washed out of the body in the urine. Stones up to size one to two cm, favourably placed in the urinary system can be effectively treated by this system with clearance rates ranging from 50% to 90%. The advantage of avoiding anaesthesia and surgery is countered with possibility of incomplete clearance and re-treatment.
This procedure of removal of stone from a 1 cm incision using nephroscope has revolutionized the treatment of stone. In the hands of experts, >95% clearance rates are achieved, even in large sized stones. In uneventful surgery, all tubes are removed and patient is discharged on 3 rd to 4 th day after surgery. These high success rates are associated with small risk of excessive bleeding requiring blood transfusion or severe infection.
Stones in the kidney are burned with LASER using a specialized very thin flexible ureterorenoscope. This is a scar-less procedure in which the stone is accessed using the natural tract
Stones lying in the ureter are removed with the help of a specialised scope.
Stones in urinary bladder removed after crushing with specialised forceps, using cystoscope.
This is another modality used in very specific circumstanced dictated by bulk of stones and their position in the renal system. Only surgeons having large experience in advanced laparoscopy undertake this type of surgery.
In the modern era of spectacular technological advancement, this is like stone-age. In modern urology practice, open stone removal is rarely required. The long incision required for kidney stones is associated with a number of disadvantages like long convalescence, big, unsightly scar, and weakness to body wall.
Which modality to choose for stone treatment?
The utilisation of any one modality requires careful deliberation regarding various factors associated with stone. The consultant urologist is the best person to advice any one modality
of treatment depending upon merits of the case.
Although the operating urologist strives for complete clearance of stones, multitude of technical factors may render this impossible. In any surgical procedure, the safety of patient
is of paramount importance rather than the result of surgery. As long as the residual stones lie in the nook and corner of kidney and are not obstructing the drainage, they are usually not of significant concern. However, the patient requires regular monitoring of the stone.
Can the stones recur?
Unfortunately, the stones have a tendency to recur. In first-time stone formers, there is a 50% risk of recurrence of stone disease in ten years. Any person who has suffered from stone
requires at least an annual check up to detect recurrence, before the stone has the chance to damage the kidneys.
High-risk cases for stone recurrence
Intestinal disease with chronic diarrhea states
Pathological skeletal fractures
Urinary tract infection
What dietary precautions to be followed to decrease recurrence rates?
- Daily fluid intake should be increased to ensure a urine output of >2.5 l / 24 hours. During summer months, excessive fluid is lost due to perspiration, leading to concentration of urine and precipitation of small crystals. Increasing fluid intake decreases urine concentration and washes away the crystals, thus preventing stone formation.
- Lemonade and orange juice contain citrate, which is beneficial in preventing stone formation. One should eat at least one orange/lemon per day
- Animal protein increases urinary solute load, thus increasing chances of stone formation.
- High sodium (table salt) intake increases stone formation
- Low carbohydrate-high protein-high fat diet promotes stone formation
- Dietary calcium avoidance paradoxically increases recurrence rates. Calcium supplementation is safest when taken with meals. Milk contains the safest variety of calcium, up to half litres of milk and milk products can be safely taken.
- Vitamin C should be restricted to < 2 gm per day.
Ignoring or neglecting stone disease can be potentially dangerous for the kidneys and overall
longetivity of the patient. Consultation with an urologist is required to properly evaluate and
treat stone disease in the most effective way with minimal discomfort to the patient.
Diet for kidney stones
- Water hardness no affect
- Drink at least 3 L of water per day to maintain urine output more than 2.5 L per day.
- Citrus juices, especially lemon and orange may be useful addition.
- Decreased risk with increased volume of water, decaffeinated coffee, tea, beer, and wine.
- Increased risk with soft drinks/soda
- Diet rich in fruits and vegetables
- More whole grain foods, fish, poultry and nuts
- Moderate in low fat dairy products
- Limit sodium (table salt), sweets, sugary drinks and red meat
- Consumption of low carbohydrate, high-protein diet increases risk of stone formation and bone loss.
- Low oxalate diet is useful in patients with intestinal problems or who have undergone bariatric surgery.
- Calcium supplementation, especially calcium carbonate does not increase the risk of stone formation, while maintaining calcium levels.
- Vitamin D repletion is probably safe.
General Health and Kidney stones
- Obesity increases risk, especially in women.
- Metabolic syndrome consists of glucose intolerance, elevated BP, dyslipidemia and central obesity increases risk.