Healthy kidneys clean waste from the blood and remove it in the urine. They control the levels of sodium, potassium and calcium in the blood. Urine contains many dissolved minerals and salts. When the urine has high levels of these minerals and salts, stones are formed. Kidney stones can affect any part of the urinary tract, from the kidneys to bladder. Often, stones form when the urine becomes concentrated, allowing minerals to crystallize and stick together.
Kidney stones start small but can grow larger in size, even filling the inner hollow structures of the kidney. Some stones stay in the kidney, and do not cause any problems. However, some travel down the ureter, the tube between the kidney and the bladder. If the stone reaches the bladder, it can be passed out of the body in urine. If the stone becomes lodged in the ureter, it blocks the urine flow from that kidney and causes pain.
Types of Kidneys Stones
Calcium stones: This accounts for 80% of kidney stones which are calcium oxalate and calcium phosphate. Calcium oxalate is the most common type of calcium stone.
Uric acid stones: This is a waste product that comes from chemical changes in the body and accounts for 5-10% of stones. Uric acid crystals do not dissolve well in acidic urine and instead will form a uric acid stone.
Struvite/infection stones: They are not common and are related to chronic urinary tract infections (UTIs). Some bacteria make the urine less acidic and more basic or alkaline. Magnesium ammonium phosphate which are the struvite stones form in alkaline urine, they are often large, with branches, and grow very fast. They account for 10%.
Cystine stones: It’s an amino acid found in certain foods which is one of the building blocks of protein. Cystinuria (too much cystine in the urine) is a rare, inherited metabolic disorder that causes the kidneys not to reabsorb cystine from the urine. When there are high amounts of cystine in the urine, stones to formed. This often start to form in childhood.
Causes
- Low Urine Volume due to dehydration (loss of body fluids) from hard exercise, working or living in a hot place, or not drinking enough fluids.
- Diet. Eating food with too much salt or sugar as fructose correlates with increasing risk of developing a kidney stone. Diet high in animal protein, such as beef, fish, chicken and pork, increase the acid levels in the body and urine. This high level makes it easier for calcium oxalate and uric acid stones to form.
- Bowel Conditions such as Crohn’s Disease or ulcerative colitis; or surgeries such as gastric bypass surgery can increase the risk of forming calcium oxalate kidney stones.
- Obesity
- Medical conditions such as abnormal growth of one or more of the parathyroid glands, which control calcium metabolism, can cause high calcium levels in the blood and urine. Distal renal tubular acidosis, a condition that causes acid build-up in the body, can raise the risk of calcium phosphate kidney stones.
- Rare inherited disorders such as cystinuria and family history
- Medication such as calcium and vitamin C supplements
Symptoms
- sharp, cramping pain in the back and side
- nausea or vomiting
- fever and chills
- urine that smells bad or looks cloudy
- feeling of intense need to urinate.
- urinating more often or a burning feeling during urination.
- urine that is dark or red due to blood
- For men, there may be pain at the tip of the penis.
Diagnosis
- Physical examination
- Medical and Dietary History
- Blood and Urine Tests
- CT scan
- X-ray
Treatment
This depends on the type of stone, severity and length of symptoms.
- One can wait for the stone to pass as smaller stones are more likely than larger stones to pass on their own. 4-6 weeks is safe as long as the pain is bearable and without no sin of infection. Good amount of water is essential to facilitate its passage.
- Medication such as Tamsulosin (Flomax) relaxes the ureter, making it easier for the stone to pass. Analgesic and anti-nausea medicine can be used to prevent pain and nausea.
- Surgery. This may be needed if:
- the stone fails to pass.
- the pain is too great to wait for the stone to pass.
- the stone is affecting kidney function.
- blocking the flow of urine from the kidney.
The surgeries are:
- Shock wave lithotripsy (SWL). It is a non-invasive procedure that uses high-energy sound waves to blast the stones into fragments that are then more easily passed out in the urine.
- Ureteroscopy (URS), is an endoscope inserted through the ureter to retrieve or obliterate the stone.
- Percutaneous nephrolithotomy
Prevention
- Drink enough water
- Eat more fruits and vegetables
- Reduce excess salt in your diet.
- Exercise and reduce weight
- Eat foods with low oxalate levels and meat
Passing kidney stones can be quite painful, but the stones usually cause no permanent damage if they’re detected early. So, hydrate and eat well!