Myths In Urology

There are many medical practices which are passed down through generations because they seem to be logical and rational. However in today’s era of evidence based medicine  we must be sure that our every clinical decision must have enough evidence to justify that practice.  There are many practices in urology which have been proven to be scientifically irrational but are still widely practiced by doctors from other specialties while managing patients with urological problems. This article aims to highlight few such practices and also present the facts why these must be given up.

1. Myth: Hydrotherapy can flush out urinary calculi.
Fact: In an obstructed upper urinary tract, excessive fluid intake leads to increase in intraluminal pressures resulting in dilatation of the collecting system proximal to the obstruction. This impedes ureteric peristalsis and hampers the distal migration of the stone. Furthermore it may aggravate the pain, vomiting and may also cause calyceal rupture, extravasation of urine in the peri-renal space which may lead to urinoma formation. If the obstructed renal unit is unable to excrete the urine then the unobstructed renal unit will excrete this excess fluid, thus negating any beneficial effect on the passage of the stone. If the obstructed renal unit has infection then, increase in intrarenal pressure leads to pyelo-venous and pyelo-lymphatic back flow of the urine. This may lead to septicemia which may be life threatening. It must be known that an obstructed urinary tract with infection is a urologic emergency! Thus overhydration of patients with renal or ureteric colic has no scientific basis. It does not befit the patient, increases the risk of life threatening complications and also the cost of treatment.
Conservative treatment is indicated only for small ureteric calculi (<5 mm). For this the patients are kept normally hydrated. Monitoring is required for deteriorating symptoms/hydronephrosis or infection of the renal unit which are indications for intervention.

2. Myth: ESWL can be used to treat renal calculi of any size.
Fact: ESWL is used to treat only small renal calculi. If ESWL is used to fragment larger renal calculi then these fragments will block the ureter, a condition known as “Steinstrasse”. Some of these fragments may remain in the kidney and lead to a recurrence. Thus ESWL for large renal calculi has poor success rates and is associated with a high risk of ancillary treatments for the residual calculi. For large renal calculi (ie > 20 mm or > 10 mm in lower pole) Endoscopic Surgery ie. Percutaneous Nephrolithotomy (PCNL) is recommended.  ESWL is also not suitable for obese patients if the stone to skin distance is > 10 cm as the shock waves cannot be focused beyond this distance. Thus ESWL cannot be recommended as a universal treatment for all renal calculi but must be used selectively.

3. Myth: Staghorn or large renal calculi cannot be treated by endoscopic surgery ie PCNL.
Fact: Open surgery for renal calculi is still practiced by few surgeons and some justify it by saying that it was done because the stone was “very large”. However PCNL is “the treatment of choice” for large renal calculi, irrespective of the stone size.

4. Myth: Beer helps in reducing kidney stones.
Fact: Beer or alcohol has a diuretic effect which may help to expel a small ureteric stone but this can also be achieved by consumption of other oral fluids or even water. In factr excess beer intake increases the risk of oxalate renal calculi by increasing oxalate and urate content in urine.

5. Myth: Restriction of calcium in the diet helps to reduce urinary stone recurrence.
Fact: Calcium is a major component of 75% of stones hence many people believe that restriction of dietary calcium is a logical means of preventing a recurrence. However several studies have shown that severe restriction of calcium in the diet actually increases the recurrence rate of urolithiasis by increasing the oxalate absorption from the intestine.

6. Myth: There are medicines to dissolve urinary stones.
Fact: 80% of the urinary stones are composed of calcium oxalate or calcium phosphate. For these there are no medicines available that can dissolve the stones. In select patients with small uric acid stones (5 % of stones) or cystine stones (1-3% of stones), medications can potentially be used to help dissolve their stones. However, even in these, surgery may required.

7. Myth: Urinary alkalizers dissolve small renal stones
Fact: Urinary alkalizers contain potassium, citrate and magnesium which act as stone inhibitors. They prevent crystallization of the “stone forming salts” in patients having calcium containing stones. However they do not dissolve an already formed stone. They are recommended to prevent a recurrence once definitive treatment of the existing stones is done ie. once the patient is stone free. For this, they must be taken regularly for 3-4 years, the period when the risk of recurrence is highest.

8. Myth: Hard tap water increases the risk of urolithiasis
Fact: Many people believe that drinking “hard” tap water, which contains more dissolved minerals (eg. calcium & magnesium), increases the risk of urolithiasis. However, most studies show that the hardness of water, determined by the content of calcium carbonate, does not affect the stone prevalence.

9. Myth: Clamp the catheter intermittently to maintain bladder tone.
This custom is also known as bladder training. Those who practice this, believe that bladder shrinks after catheterization and that bladder training helps the bladder to regain its lost tone.
Fact: The contractile function of the bladder is an autonomous activity and a normal bladder cannot be trained to behave like normal.  There is no evidence that cyclical bladder filling has any positive effect on bladder tone. A normal bladder retains its volume, tone and the capacity to contract during voiding even after long periods of catheterisation. In fact this practice increases the risk of urinary tract infection by producing  stagnant urine at high pressure.
In case of chronic (painless) retention this practice leads to over distention of the bladder which is detrimental for the recovery of bladder tone. In chronic retention the catheter is kept indwelling for 1-2 months. Any kind so called bladder training in such cases does more harm than good.

10. Myth: Chronic retention must be relieved slowly to avoid hematuria and diuresis.
Fact: It is believed that slow bladder decompression avoids a sudden fall in intravesical pressure  and thus decreases the chance of hematuria. However recent studies do not support this theory. It is now known that removal of even a small volume of urine in such cases leads to a drastic fall in intravesical pressures.  The hematuria that occurs after decompression is usually self limiting and generally does not require any active intervention. The diuresis that ensues after bladder decompression has a beneficial effect of excretion of retained salt and water reversing the effects of extracellular fluid overload. However during the period of diuresis the patient must be monitored with hourly urine output and BP charting as these patient can develop hypotention due to sudden fluid shift. Intravenous fluids are not generally required unless there is a drop in blood pressure and/or electrolyte imbalance. Overenthusiastic fluid replacement will only prolong the diuresis.

11. Myth: Peri-catheter leak is due to small lumen of catheter hence replace it with a bigger one.
Fact: Once a blocked catheter is clinically ruled out as a cause of the leak, pericatheter leak is usually caused due to uninhibited detrusor contractions due to irritation of the bladder by the catheter which is a foreign body. The larger the catheter/balloon, the higher will be the leak.  This can be prevented by filling the balloon to only 8-10 ml. Anticholinergics (oxybutinin or terodiline) are used to treat this problem. Replacing the catheter with a bigger one will only worsen the problem and also increases the risk of urethritis and urethral stricture formation. The dictum for catheter selection is to use the smallest lumen that will serve the purpose. For patients with clear urine 12-16 French size is adequate for urinary drainage.

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