THIRUVANANTHAPURAM: U rinary stone disease is a very common health issue. This disease has significant social impact also as it may cause significant pain and morbidity which would require abstinence from work and loss of productive hours.
Symptoms
The most common symptom caused by urinary stones is pain. The location of pain would vary depending on the location of the stone. A stone that obstructs the ureter or renal pelvis causes excruciating, intermittent pain that radiates from the flank to the groin or to the inner thigh. This pain, known as renal colic, is often described as one of the strongest pain sensations known. Renal colic caused by kidney stones is commonly accompanied by urinary urgency, restlessness, hematuria (blood in urine), sweating, nausea, and vomiting. Fever that accompanies pain due to urinary stones may be an ominous sign that points towards infection. This would mandate prompt treatment for relieving obstruction due to stone and also aggressive treatment of infection.
How are urinary stones diagnosed?
The above mentioned symptoms point towards a diagnosis of urinary stones. This needs to be confirmed with imaging studies to confirm the diagnosis of stone disease. The common tests performed are Urine analysis, Ultrasound scan (USS) and X ray of the abdomen. CT scan is also increasingly being used to diagnose stone disease and would be the best test to correctly diagnose and locate urinary stones. Additional information like clues to the hardness of stones can also be ascertained with CT scan.
Is there any age for urinary stone disease?
Stone disease may be seen from infancy to old age. However occurrence of stones in children mandates detailed evaluation to rule out any metabolic diseases that would predispose to stone disease. Men have 3-4 times greater chance of development of urinary stones.
How are stones formed in the urinary tract?
Stones that form in the urinary tract can be of varying chemical composition. Urinary stones form in concentrated urine when crystals formed from calcium, oxalate, phosphate, cystine, uric acid etc precipitate in urine. These crystals accumulate to form stones which grow in size with further accumulation of crystals. Epitaxy is the term used to denote overgrowth of one type of crystal on the surface of a preexisting one that is of different type. This kind of nucleation with different crystals are seen with calcium phosphate and uric acid facilitating the crystallization of calcium oxalate salt. There are various organic (eg - glycosaminoglycans, nephrocalcin, Tamm-Horsfall protein, uropontin) and inorganic (eg - citrate, pyrophosphate) substances in urine that are inhibitors of stone formation.
How are urinary stones treated?
The decision to treat urinary stones depend on various factors like location and size of stones, presence of obstruction to urinary tract, co existing alteration in kidney function, co existing urinary infection etc. Small stones in the kidneys are usually treated with medicines. When these stones are expelled, there is a chance of occurrence of pain. This is usually treated with painkillers, but further treatment would be ultimately determined by the patient’s ability to tolerate pain and constraints and circumstances of the patient.
Procedures that are done to clear urinary stones
All treatment modalities may not suit to clear a given stone. The following are the usual procedures adopted to clear urinary stones - ESWL (Extra-corporeal Shock Wave Lithotripsy) - This modality uses shock waves to fragment stones inside the kidney or upper ureter. The stone which is broken down into fragments is then passed through urine.PCNL (Per Cutaneous Nephro Lithotripsy) - This is a minimally invasive surgery involving introduction of in instrument directly into the kidney to clear stones. This is a kind of ‘key hole’ surgery for kidney stones.
Ureteroscopy - This procedure involves introduction of instruments through the urethra into the bladder and then into the ureter to visualize the stone and fragment the stones. Ureteric stones are best treated by this method. Flexible ureteroscopy is introduced into the ureter or kidney to tackle stones. Stones are fragmented using either laser energy or a pneumatic lithotriptor, which uses mechanical energy to fragment stones. Flexible ureteroscopy to clear kidney stones is also called as RIRS (Retrograde Intra Renal Surgery).
Cystolitholapaxy - This is the process of breaking bladder stones mechanically with an instrument called lithotrite. This instrument is introduced into the bladder through the urethra.
Laparoscopy - This is another kind of ‘key hole’ surgery to clear selected stones in the kidney or ureter.
Preventive measure for all kinds of stones would involve maintaining a high fluid intake. Fluid intake is maintained such that an average adult produces more than two litres of urine per day.The patient can easily self monitor the adequacy of fluid intake by watching the colour of urine. To prevent stone formation, urine should be dilute which is indicated by a colourless or pale yellow coloured urine. As regards management of urinary stones is concerned, it is always better to prevent stones rather that treating them after they are formed.
The views expressed by the author are her own.
The author is a Consultant Urologist and Transplant Surgeon at KIMS, Thiruvananthapuram.