#Uti and staghorn calculus free#

The latter two, bicarbonate and OH – raise the pH of the solution (urine in our case). The result is two ammonium ions a bicarbonate ion, and a hydroxyl ion (OH – the alkaline radical, as protons (H +) are the acid radical). Because urea is a molecule with one carbon atom, one oxygen atom, and two nitrogen atoms, hydrolysis means that water reacts this way with the urea: But if the enzyme urease is added hydrolysis rate rises 10,000 fold meaning it occurs in minutes. It will occur by itself.ĭespite this potential, urea is very stable in urine, with a 1/2 life of over 3 years. If water combines with urea so this structure comes apart, the energy that was used to make the chemical bonds is released, so the reaction of ‘hydrolysis’, bonds lysed (broken) by water combining, is energetically favored. By this I mean, it is like supersaturation and crystals. In water, urea has the chemical potential to decompose by hydrolysis. Here it is as a stick figure – a single carbon atom (C) double bonded to a single oxygen (O) and two nitrogens. It is concentrated in urine by kidneys as they conserve water, and specifically because urea is part of the machinery kidneys use for that water conservation. Water spontaneously combines with urea to take it apart, releasing ammonia.Īll mammals excrete urea as an end product of nitrogen metabolism. Hydrolysis means lysis (taking apart) by water (hydro). This latent saturation arises from hydrolysis of urea.

#Uti and staghorn calculus free#

The bacteria themselves provide the free energy for crystallization through their multiplication, and unleash a saturation latent in normal urine. Utterly unlike the calcium and uric acid stones, or less common cystine stones or even drug stones, struvite stones do not rely at all on kidney water conservation to produce supersaturation sufficient to nucleate crystals.

This will seem foreign and technical, but I advise interested patients to read it because once one understands just what is happening prevention and treatment will be immediately clear. Of the crystals, struvite is most common and arises as bacterial lodge on catheter walls and on urothelium whose defenses are reduced by the catheterization.

As one might presuppose, factors that raise the risk of infection stones include congenital or acquired urinary tract malformations, obstruction, catheters left in for any significant amount of time, and urological procedures themselves.Ĭhronic indwelling urinary catheters are an ideal locale for bacteria to lodge and form crystals. The combination of obstruction, infection, and large masses of crystal themselves not rarely injure kidneys and reduce kidney function. Unlike the common calcium and uric acid stones, struvite stones do not so often pass as grow in the kidney to cause flank pain and, being infected, fever, along with bleeding and slowly developing obstruction. Surgery is usually percutaneous nephrolithotomy. Not rarely they enlarge so as to fill the collecting system causing so called stag horn stones. They are often large, and by nature infected. This straightforward and useful clinical review tells us that struvite stones comprise about 10 – 15% of urinary (kidney and bladder) stones, and are more common in women. The beautiful photograph of a struvite stone is by Susumu Nishinage (from the remarkable photographic collection ‘ Science Photo Library Art’, part of finartamerica. I have already placed struvite stones within the pantheon of stone disease. Certain bacteria can decompose urea in urine to ammonia creating conditions that promote crystallization of ammonium ion with the phosphate and magnesium normally present in urine. Struvite is a composite of magnesium, ammonium ion, and phosphate ion. The term ‘infection stones’ means stones caused by the action of bacteria.Īt the present time only struvite stones belong in this category.