Kidney Stones

HOW DO KIDNEY STONES FORM?

Everyone forms crystals in their urine, even people who never form kidney stones. Urine, which is produced in the kidneys, naturally contains substances that promote the development of crystals. These stone promoters include calcium, oxalate, sodium, phosphorus and uric acid (and also cystine, in the case
of individuals with the inherited disorder known as cystinuria).

These stone-promoting compounds, which come from the bloodstream, are present in urine because the kidneys filter our blood and regulate whether and how much of these urinary constituents will be reabsorbed by the kidneys (put back into blood circulation) or eliminated as waste.

In addition to these stone promoters, urine also naturally contains proteins and other compounds that inhibit crystal formation. Examples of stone inhibitors in urine include total urine volume, citrate, magnesium, pyrophosphate, phytate and proteins and other molecules derived from normal metabolism, collectively referred to as urinary macromolecules. These inhibitor said the elimination of crystals before they attach to the kidney and grow into larger stones.

Thus, if the crystals remain small enough, and if the urine is dilute enough to avoid super saturation, crystals will flow with urine through the ureters and bladder without being noticed or causing problems. However, this balance between stone promoters and inhibitors does not exist for everyone - either due to genetic, lifestyle or other factors - leading to the formation of kidney stones.

SYMPTOMS THAT SHOW PRESENCE OF KIDNEY STONE

Stones in Kidney :

If there are stones inside your kidney, you will usually not get any pain in your abdomen. However, if the stone is big enough, you might experience dull aching pain.Sometimes renal stones are diagnosed without any symptoms, as incidentally detected during other diagnostic modalities.

Stones in Ureter :

If there is a stone inside your ureter (the tube that passes from the kidney to the urinary bladder), you will get a sharp pain which starts from either of the loin depending on which side the stone is situated and the pain will spread down to your lower abdomen. The pain will be agonizing enough for you to seek medical help at the earliest.

If there are stones lodged inside both ureters, there is every possibility that you might not pass urine at all, in addition to pain in both loins. This is due to ureteric obstruction on both sides leading to acute kidney failure. In such a situation, you should seek emergency medical care. In these sorts of situations, your urologist will advise a procedure called bilateral ureteric stenting in which tubes will be inserted into both your ureters by going through the normal urinary passage. Such a procedure will relieve you of the pain and will also improve your kidney function. However, this procedure is only a temporary one and once your kidney function stabilizes, you will need a surgical procedure to remove the stones in both your ureters.

Stones in Ureterovesical Junction:

If there are stones lodged in this part of the ureter (the point where the ureter enters the urinary bladder), you will experience symptoms like burning sensation/pain while passing urine with increased frequency of urination in addition to loin pain. You might also pass blood in the urine.

Stones in Urinary Bladder:

If there are stones inside your urinary bladder (the organ that stores urine after receiving it from the kidneys), you might experience symptoms like burning sensation/pain while passing urine with increased frequency of urination with passage of blood in the urine. There might also be a sensation of urgency to pass urine.

Stones in Urethra:

If the stone has lodged in the urethra (the tube that leads from urinary bladder to the natural urinary orifice), you will have a blocked sensation while passing urine with slowness in the urinary stream. This is different from stones in Ureter (the tube that passes from the kidney to the urinary bladder)

TREATMENT OPTIONS

There are two ways by which you may be managed by your urologist.

A. Medical management:

For stones which are within the kidney and which are less than 10mm, the urologist will advise you to drink plenty of fluids and probably give you some medications which might help prevent stone formation. .Stones bigger than 10mm might need some form of surgical intervention.

For stones which are inside the ureter, the urologist will give you some pain killer medications and advise plenty of fluid intake if the stones are less than 10mm. Stones bigger than 10mm might need some form of surgical intervention.

B.Definitive management:

ESWL (EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY):

In this procedure, stones which are upto1.5mm inside the kidney or in the upper ureter can be fragmented. This is usually done as a day care procedure wherein you can get discharged in the evening after undergoing the procedure in the morning. You will be subjected to shock waves emanating from a machine that will break the stones. No anaesthesia is required. The main disadvantage of this procedure is that not all stones can be fragmented with this procedure and even if the stones do fragment well, there may be a delay in passage of the fragments (sometimes upto 6 weeks). Complications are that you might get pain till all fragments are passed in the urine. If the fragments don’t pass out,you will need other procedures to remove the stones.

PCNL (PERCUTANEOUS NEPHROLITHOTOMY):

Here, stones within the kidney are removed by making a small key hole in your back. The stones are removed by a rigid straight instrument called the nephroscope and you can go home in 3 days and return back to your normal activities in a matter of a couple of days. Complications are bleeding which may require blood transfusion and sometimes a procedure called renal angioembolization (a coil is placed in the blood vessel that has ruptured and has led to bleeding) may be required.

LASER KIDNEY STONE TREATMENT (or) RIRS (RETROGRADE INTRARENAL SURGERY OR FLEXIBLE URETEROSCOPY):

In this method, stones are removed by passing a flexible tube through the normal urinary passage. Stones within the kidney are fragmented using laser and removed. Stones of upto 3.5cm can be removed. Only a single day’s hospital stay is required. There are practically no chances of bleeding in contrast to PCNL and you can return to your routine activity the next day. However, the procedure is a bit expensive. This procedure is also a less morbid one than PCNL.

URS (SEMIRIGID URETEROSCOPY):

Here, stones within the ureter are removed by passing a straight tube via the natural urinary passage. Only a single day’s hospital stay is required and you can return to your routine activity the next day. Complications are that it may result in injury to the ureter.

In URS, PCNL and RIRS, the urologist may place a tube inside your ureter called a ureteric stent. This is to allow the normal urine flow from the kidney to the urinary bladder and also to allow some tiny stone fragments to pass out. The stent usually remains in place for up to 3 weeks after which it can be removed as a day care procedure under local anaesthesia. With the stent inside your body, you can carry on your regular activities and return to work but do make sure that you get it removed on the date stipulated by your urologist.The stent can cause minor problems to you like burning sensation while passing urine or a pain in the side of the loin where it has been inserted. This pain is usually due to the reverse passage of urine from the urinary bladder to the kidney and will gradually subside with time as the stent and ureter adapt themselves. In case these symptoms persist, you must seek medical care. If the stents are not removed for long time, it will be crystalized slowly and transformed into stones which can permanently damage your kidney. Hence removal of DJ Stent is must.

CYSTOLITHOTRIPSY:

Stones within the urinary bladder that are larger than 10mm are removed by this method. Here a straight tube is inserted into your urinary bladder via the natural urinary passage and the stone is broken and removed. This method is also used for stones within the urethra. Only a single day’s hospital stay is required

OPEN CYSTOLITHOTOMY:

Stones within the urinary bladder that cannot be removed by cystolithotripsy are removed by this method.
Here an open surgery is required and you will need 4 to 5 days of hospitalization.

COMPLICATIONS

General complications include urinary tract infection (symptoms may be fever with loin pain and burning sensation while passing urine) and stent related problems which have been highlighted before. Complications specific to the procedures have been enumerated previously.