Kidney Stone - MITR
Kidney Stone
URINARY STONES
Urinary stones are conglomeration of multiple small crystals of chemicals like calcium, oxalate, phosphate, uric acid, xanthine.
They are expelled out of body through natural body tubes called ureter and urethra. Stones are formed almost always in kidney exception being bladder stones which are formed due to obstruction to urine passage outlet.
These stones look like any stones you would find in geological museums with a wide variety of colours, hardness, texture and shapes.
Causes of stones
These stones form in the kidneys when the conditions favour their formation.
Firstly, some people are more prone than others i.e they have metabolic reasons to form more chemicals in the urine.
Secondly, there can be structural abnormalities in the urinary tract leading to stagnation of urine and thus leading to increased chances of crystals getting converted to stones.
hirdly, urinary ph, and infection in urine lead to increased accumulation of certain chemicals like ammonia leading to large sized stones almost resembling horn of a stag.
Symptoms:
➾ Pain
➾ Blood in urine
➾ Fever
➾ Vomiting
➾ Strangury
Natural expulsion
Just like urine which keeps moving out of the system by waves generated by the body, these stones also move along the waves to be expelled out.
Whenever these stones get stuck at some point in the path pressure builds up in the kidney and kidney gets balooned up causing pain. This swelling in the kidney is called as hydronephrosis. If the stone passes off, then hydronephrosis obviously dissapears. If the stone persists for a longer time hydronephrosis becomes irreversible and is pemanent even if the stone has passed out. This is called as residual hydronephrosis.
Evaluation
A detailed history of present ant past pains with complete details of natural expulsion and procedures is done. Investigations like ultrasound, creatinine, IVU, CT –IVU is perfomed to know the status of stone and kidney. Occasionally isotope renal scan is done to know the exact function of each kidney.
Treatment
Natural expulsion of stones is possible with tiny stones and in drainage systems of people with history of regular lithuria(stone in voided urine).
People needing any intervention by a urologist are the ones whose stones have got stuck up at some point in the whole tract or when stone is causing reduction of kidney function due to infection or obstruction.
Pain may or may not persist when the stone is lodged in the tract blocking the path of urine. Reduction in pain is a natural mechanism by body wherein the volume of urine generated by that kidney is reduced. Persistence of this reduction causes kidney to initially function sub-normally and to completely stop functioning later.
Treatment methods
➾ ESWL(Extracorporeal shock wave lithotripsy)
➾ Endoscopic removal of stones
➾ Laparoscopic removal of stones
➾ Combined techniques
➾ Medical dissolution of stones in rare variety of stones.
ESWL(Extra –corporeal shock wave lithotripsy)
Shock wave lithotripsy is an out-patient procedure where a modified sound wave is focussed on to the stone while visualising it by sonography or x-ray. Stone is fragmented and it passes off the normal urinary tract like tiny stones do.
The selection of this procedure is based on the size, site and impaction of the stone. 2 to 4 sittings are needed for harder stones and complete clearance.
Sometimes the fragments of stone come together and can get jammed in the ureter(pipe that carries urine from kidney to bladder). This can lead to severe pain or infection. It is corrected by placing a stent across the fragments and thus bypassing the block till all stones have cleared up. Some larger stones will need pre-stenting before ESWL to prevent the above said complication.
ESWL(Extra –corporeal shock wave lithotripsy)
Shock wave lithotripsy is an out-patient procedure where a modified sound wave is focussed on to the stone while visualising it by sonography or x-ray. Stone is fragmented and it passes off the normal urinary tract like tiny stones do.
The selection of this procedure is based on the size, site and impaction of the stone. 2 to 4 sittings are needed for harder stones and complete clearance.
Sometimes the fragments of stone come together and can get jammed in the ureter(pipe that carries urine from kidney to bladder). This can lead to severe pain or infection. It is corrected by placing a stent across the fragments and thus bypassing the block till all stones have cleared up. Some larger stones will need pre-stenting before ESWL to prevent the above said complication.
Endoscopic Techniques
PCNL(Percutaneous Nephrolithotomy)
A tiny hole made in the back takes the telescope into the kidney and removes the stones either by fragmenting it or by directly picking it up.
Patient needs to be admitted in the hospital for 2 days till he is comfortable and the tubes inserted during procedure are removed. It requires anesthesia to be given before the procedure and occasionally pain killers may be needed for 1 or 2 days.
The stones suitable for this procedure are large stones (more than 20 mm) and stones in special locations like pockets in the kidney(diverticulum).
URS (uretero-renoscopy)
A telescope which is has the diameter of a ballpoint refill inserted under anesthesia through natural urine passage and carried into ureter and kidney. Stone is visualized on a large screen and fragmentesd using a suitable energy source.
It is a day care procedure where patient walks out of the center in 6 hours .
Ureteric stones of any size and kidney stones for less than 20 mm size are easily treated by this technique.
Two varieties are available – Flexi and semirigid.
Cystoscopic removal
A rigid or flexi cystoscope is inserted through natural urinary opening and stone removed intact or after fragmentation.
PCCL(Percutaneous cystolithotrity)
A small puncture just below umbilicus leads a telescope directly into bladder thus avoiding natural urine passage which is important in children and unfit adults.
Laparoscopic removal of stones
Large stones in the ureter and renal pelvis are removed by laparoscopic technique thus avoiding long period instrumentation of ureters and thus removing the stone intact.
Patients need to stay for 24 hours in the urology center.
Combined techniques
For large and complex stones 2 or more than two techniques are utilized for complete stone clearance. They can either be in one sitting or in multiple sittings as deemed fit.
Medical dissolution of stones
Rare stones like pure uric acid stones, small infection stones and stones due to medications for HIV can be dissolved with oral medications.
Complications
Untreated long standing stones can cause failure of that kidney. Recurrent infections can lead to decrease in the function of the kidney. Severe infections especially in diabetics can be life threatening. Occasionally, bleeding in urine can be very severe. Blockage of common tract called urethra can cause retention of urine. Simultaneous blockage of both ureters can cause life threatening anuria(no urine formation).