Our Urine contains many dissolved minerals and salts. When the levels of these minerals and salts increase, stones form in the urinary tract. Kidney stones initially start as a small nucleus and as more and more minerals and salts are deposited over the nucleus, a big kidney stone forms, that may even fill the whole of the kidney. Some stones stay in the kidney, and do not cause any problems. Sometimes, the kidney stone can travel down the ureter, the tube between the kidney and the bladder. If the stone becomes stuck in the ureter, it blocks the urine flow from that kidney and causes swelling of kidney and pain.
What is Kidney Stones Made of?
Kidney stones come in many different types and colours. How you treat them and stop new stones from forming depends on the composition of stones.
Calcium stones (80 percent of stones)
Calcium stones are the most common type of kidney stone. There are two types of calcium stones: calcium oxalate and calcium phosphate. Calcium oxalate is by far the most common type of calcium stone. Some people have too much calcium in their urine, raising their risk of calcium stones. Even with normal amounts of calcium in the urine, calcium stones may form for other reasons.
Uric Acid stones (5-10 percent of stones)
Uric acid is a waste product that comes from chemical changes in the body. Uric acid crystals do not dissolve well in acidic urine and instead will form a uric acid stone.
Causes of Acidic Urine are:
Chronic diarrhoea Disease
diabetes (high blood sugar)
High animal protein and less fruits and vegetables in diet.
Struvite / infection stones (10 percent of stones)
These stones are related to Urinary Tract Infections (UTIs). Some bacteria make the urine alkaline. Magnesium ammonium phosphate (struvite) stones form in alkaline urine. These are often large stones.
Cystine stones (less than 1 percent of stones)
Cystine is an amino acid that is in certain foods; it is one of the building blocks of protein. Cystinuria (too much cystine in the urine) is a rare, inherited metabolic disorder. When there is high concentration of cystine in urine, it causes stones to form. Cystine stones are often seen in children.
Causes of low urine volume are: dehydration from heavy exercise, working or living in a hot environment, or not drinking enough fluids. When urine volume is low, urine is concentrated and dark in color. Concentrated urine means there is less fluid to keep salts dissolved. So kidney stones may form.
Adults should drink enough fluid to make at least 2.5 litres of urine every day.
Diet can also affect the chance of forming a stone.
One of the more common causes of calcium kidney stones is high levels of calcium in the urine.
Methods to reduce urinary calcium excretion are reduce dietary calcium intake and by decreasing the sodium (salt) intake.
Too much salt in the diet is a risk factor for calcium stones.
Eating foods rich in oxalate can raise your risk of forming calcium oxalate stones.
A diet high in animal protein, such as beef, fish, chicken and pork, can raise the acid levels in the body and in the urine. High acid levels increase risk of formation of calcium oxalate and uric acid stones.
The breakdown of meat into uric acid also raises the chance that both calcium and uric acid stones will form.
Certain bowel conditions that cause Diarrhoea (such as Crohn's Disease or ulcerative colitis) or previous surgeries (such as gastric bypass surgery) can raise the risk of forming calcium oxalate kidney stones.
Obesity is a risk factor for stones. Obesity may increase the acid levels in the urine, leading to uric acid stone formation.
Certain diseases have an increased risk of kidney stones. Hyperparathyroidism can cause high calcium levels in the blood and urine. This can lead to calcium oxalate kidney stones.
Another condition called Distal Renal Tubular Acidosis, in which there is acid build-up in the body, can raise the risk of calcium phosphate kidney stones.
Some rare, inherited disorders can also make certain types of stones more likely. Examples include cystinuria, which is too much of the amino acid cystine in the urine, and primary hyperoxaluria, in which the liver makes too much oxalate.
Some medications, and calcium and vitamin C supplements, may increase your risk of forming stones. Be sure to tell your health care provider all the medications and supplements you take, as these could affect your risk of stone formation. Do not stop taking any of these unless your health care provider tells you to do so.
The chance of having kidney stones is much higher if you have a family history of stones, such as a parent or sibling.
What is the treatment of Kidney Stones?
There are different treatments to choose from. It is important to talk to your health care provider about what is best for you?
Wait for the stone to pass on its own
If stone is less than 5mm in size, it has more than 50% chance to pass on its own.
You may wait for up to 4 to 6 weeks for small stones to pass, if the pain is bearable and there are no signs of infection. While waiting for the stone to pass, you should drink normal amounts of water. You may need pain medication when there is pain or discomfort.
Certain medications have been shown to improve the chance that a stone will pass. The most common medication prescribed for this reason is tamsulosin. Tamsulosin relaxes the ureter, making it easier for the stone to pass. You may also need pain and anti-nausea medicine as you wait to pass the stone.
Surgery may be needed to remove a stone from the ureter or kidney if:
The stone fails to pass.
There is too much pain.
The stone is affecting kidney function.
Kidney stones should be removed by surgery if they cause repeated infections in the urine or because they are blocking the flow of urine from the kidney. Today, surgery usually involves small or no incisions (cuts), minor pain and minimal time off work.
Surgeries to remove stones in the kidneys or ureters are:
Shock wave lithotripsy (SWL)
Extracorporeal shock wave lithotripsy (ESWL) for kidney stones
Shock Wave Lithotripsy (SWL) is used to treat stones in the kidney and ureter. Shock waves are focused on the stone using X-rays or ultrasound to pinpoint the stone. Repeated firing of shock waves on the stone causes the stone to break into small pieces. These smaller pieces of stones pass out in the urine over a few weeks.
SWL does not work well on hard stones, such as cystine, some types of calcium oxalate and calcium phosphate stones, or very large stones.
With SWL, you may go home the same day as the procedure. You may be able to resume normal activities next day. You may collect the stone pieces as they pass in a strainer. These pieces will be sent to the laboratory to be tested.
Although SWL is widely used and considered very safe, it can still cause side effects. You may have blood in your urine for a few days after treatment. Most stone pieces pass painlessly. Larger pieces may get stuck in the ureter, causing pain and needing other removal procedures.
Ureteroscopic Removal of Stones
Flexible Ureteroscopy (URS) is used to treat stones in the kidney and ureter. URS involves passing a very small telescope, called an ureteroscope, into the bladder, up the ureter and into the kidney. Stones from kidney can also be removed without need for PCNL.
Procedure is done under either General Anaesthesia or Spinal Anaesthesia. Once the urologist sees the stone with the ureteroscope, , it can be broken into smaller pieces with a laser or other stone-breaking tools.
Once the stone has been removed whole or in pieces, the doctor may place a temporary stent in the ureter. A stent is a tiny, rigid plastic tube that helps hold the ureter open so that urine can drain from the kidney into the bladder. This tube is completely within the body.
You may go home the same day as the URS and can begin normal activities in 1 to 2 days. If your urologist places a stent, he or she will remove it four to 10 days later. It is very important that the stent is removed when your doctor tells you. Leaving the stent in for long periods can cause an infection and loss of kidney function.
Percutaneous Lithotripsy (PCNL) is the best treatment for large stones in the kidney. General anaesthesia or Spinal Anaesthesia is needed to do a PCNL. PCNL involves making a half-inch incision (cut) in the back or side, just large enough to allow a rigid telescope (nephroscope) to be passed into the kidney where the stone is located.
An instrument passed through the nephroscope breaks up the stone and removes the pieces using forceps.
After the PCNL, a tube is usually left in the kidney to drain urine into a bag outside of the body. This will allow for drainage of urine and stop any bleeding. The tube is left in overnight or for a few days. Hospital stay is overnight after this operation.
You can begin normal activities after about one-to-two weeks.