Types of Kidney stones – Part 2
Calcium Phosphate Stones
In our previous article, we mentioned about Calcium Oxalate Stones and how they are formed. If you want to start reading from there, you can click on the below link:
Next in line are ‘Calcium Phosphate Stones’. Before we get into the details, do you remember pH value that you studied in school? The acidity of any solution is determined by it’s pH value that ranges from 0 to 14 where 0 being most acidic and 14 being most alkaline? Everyone’s urine also has a pH value like any other liquid. If the acidity of the urine goes beyond 6.8 pH value, that will result in formation of one type of Calcium Phosphate stones called ‘Carbonate Apatite’. If the acidity of the urine ranges between 6.5 and 6.8 with high concentrations of calcium and phosphate, ‘Brushite’ stones (another type of Calcium Phosphate Stones) are formed. Brushites grow very rapidly and they recur very frequently. They are usually very hard stones that cannot be broken with Lithotripsy methods.
Struvite Stones
Bacteria that are present in the Urinary Tract produce struvite stones by breaking Urea (present in the urine) into ammonia. When the urine is more alkaline, it helps bacteria is making this type of stones. Wondering how bacteria get into urine? Mainly there are 2 ways. One is through the raw food we eat and the other is through Urinary Tract Infection. As the bacteria reach the kidneys, they start making stones by breaking Urea or they can infect already formed calcium stones to produce mixed stones. These stones grow big and fast. They block the kidney, ureter or bladder and can affect the functioning of Kidney(s) and if they enter the blood system, a condition called ‘sepsis’ can also occur. This can be seen more in women than in men but occurs in only 10 to 15% of kidney stone patients.
Treatment of Struvite stones
Though these stones occur in less number of patients, it is very important to get these stones removed because, if left untreated even for a short period of time, they can damage the kidneys very badly. If the stones are not too large, doctors use Shock Wave Lithotripsy (SWL) or Percutaneous Nephrolithotomy (PNL) to break the stones. If they are too large, an incision has to be made on the back and the stones are to be removed manually. If the urologist doesn’t find either of these two approaches appropriate, a larger incision based surgery will be performed to remove the stones. If the doctor believes that the kidney is damaged, it may also be removed.
Uric Acid Stones
These types of stones are formed by the Uric Acid present in the urine. For this type of stones, the presence of calcium or oxalate is not necessary. Uric Acid stones are reddish brown, orange in colour because, they absorb the parts of hemoglobin from the blood. In conditions when the pH value of urine is low (more acidic in nature), the uric acid crystallize very fast (in seconds) to form small gravel like stones in the urine. If these are not passed through urine, they grow very fast in to big kidney stones.
Treatment of Uric Acid Stones
Simple treatment is to make the urine more alkaline or reduce the acidic nature of urine. This can be by having more water and by using some medications that increase the alkalinity of the urine.
Cystine Stones
Cystinuria is an inherited kidney disorder. Cystine stones are formed in people who inherit cystinuria. These stones are lemon yellow in colour. People suffering from Cystinuria lose large amounts of cystine in their urine which results in the formation of Cystine stones in the kidneys. The more cystine present in their urine, the faster the stones grow in size and number. These stones attach at the ends of kidney tubes and cause damage to the kidneys. Since this is an inherited disease, children suffering from Kidney stones may have cystine stones.
Treatment of cystine stones includes consuming large amounts of water and other fluids every day. Medicines that are administered react chemically with cystine and form a compound that easily dissolves in the urine and prevent stones from forming.
Certain other rare stone types also form that are a combination of any of these stones.
Should the urologist know what types of stones are present inside the kidney?
Absolutely! It is very important for the urologist who is treating the kidney stones to know what types of stones are formed inside the patient’s kidneys. The treatment opted depends on the type of the stone and the size of the stone. As we have mentioned, in case of Uric Acid stones, reducing the acidic nature of urine is good enough to treat them whereas in the case of Struvite stones, small or large incision has to be made.
