Kidney stones or renal calculi are hard deposits of minerals and crystal, which are formed in the urine. They are common and affect up to 10% of the population.
The main risk factors for kidney stone formation are:
- Older age
- Male sex
- Family history of kidney stone
- Medical conditions such as : Hyperparathyroidism, Gout, Crohn’s disease, Medullary sponge kidney, cystinuria
What are the symptoms?
Renal stones are formed inside the kidney and often do not present with symptoms until they have been dislodged and result in blockage of the ureter, the tube that carries urine from kidney to bladder. This could result in severe pain which is often located in flanks and radiates to the groin. Other symptoms include: bleed in the urine, vomiting or painful urination.
What are the types of renal stones?
- Calcium stones: (Calcium oxalate and Calcium phosphate)
- Uric acid stones
- Magnesium Ammonium phosphate (struvite) stones
- Cystine stones
Majority of the stones (80%) contain calcium are they could be seen on X-rays. Uric acid stones are the second most common types of stone and are more associated with obesity, dehydration and gout. They are not visible on X-rays. Magnesium Ammonium phosphate stones, also known as Struvite stones, form most often in presence of infection (urea splitting bacteria). These stones can grow rapidly to become Staghorn calculi, filling the collecting system of the kidney. Cystine stones are rare and often seen in patients with history of cystinuria. These stones are often very hard and have high recurrence rates.
Treatment of Renal Stones
Treatment of kidney stones is complex and would require consultation with your urologist. The treatment is often individualized based you patient’s history and pre-existing medical condition, kidney function and size of stone. The main treatment options are:
- Observation: Smaller stones can usually be observed in most (not all) individuals as they do have good rates of spontaneously passing. These are often for stones 4 mm or smaller.
- Ureteroscopy and Laser lithotripsy: This is the most common treatment for ureteric and renal stones. It is a day procedure and performed under general anesthesia. Using a fine telescope, the urologist will access the ureter and collecting system of the kidney. Smaller stones can be extracted under direct vision using a fine basket. Larger stones are treated with laser, where a fine laser fiber is passed through the scope and the stone is broken down into dust or very small fragments which subsequently could pass.
- Shockwave lithotripsy: In this procedure, the stone is localized using X-ray and the ESWL machine delivers and converges ultrasound waves to breakdown the stone into very small fragments which in turn could spontaneously. Success rates of this procedure is variable depending on patient and stone factors. Furthermore this treatment is not suitable for all patients and your urologist will ascertain your suitability for this procedure during the consultation.
- PCNL: This treatment is reserved for patients who have larger stones or when the stone is not easily treatable with the other modalities. It is a minimally invasive surgery and is performed under general anesthetics. Patients often requires a few days of hospital stay. The surgeon accesses the kidney directly with a small puncture from the back. The stones are located and the stone is broken down and extracted under direct vision and using a stone breaking-down device.
Kidney Stone prevention
Prevention is better than cure, is certainly true for kidney stones. The general patient advice for all types of kidney is to increase fluid hydration and have a low-salt diet. However, different types of stones would require different recommendations and the wrong strategies would potentially worsen the situation.
Once the kidney stone is treated, strategies are employed to prevent stone formation in future. Often during the initial procedures, stone fragments are sent for analysis to obtain the composition and type of the stone. In some cases, a 24-hour urine test as well as a blood test is also performed to get further information about the PH as well as the quantity of different molecules and minerals in the urine. With this information at hand, individualized recommendations are made to patients to prevent stone formation in the future.