Kidney stones or renal calculi are solid deposits of crystals, usually composed of calcium oxalate, which typically occur in the kidneys, but can also develop in other parts of the urinary tract such as the bladder, urethra and the ureter. These stones can form in different sizes and are extremely painful.
Our kidneys are responsible for filtering the blood and generating urine. Kidney stones are formed when the salts and other minerals present in the urine lump together and crystallize to form small stones. Kidney stones usually present no symptoms till the time they leave the body through the ureter. These are a common cause of blood in the urine and can cause severe abdominal and back pain and even result in an infection if left untreated.
Why do kidney stones form?
- The leading cause of kidney stones is insufficient intake of water. The uric acid doesn’t become diluted enough and hence the urine becomes more acidic. This acidic environment in the urine can result in the formation of kidney stones.
- Kidney stones also form when the urine contains more crystal-forming substances such as calcium, oxalate and uric acid than the fluid in the urine can dilute.
- The kidneys are unable to process excessively high amounts of proteins, salt and glucose in the diet, which can lead to formation of kidney stones.
- Inflammatory bowel diseases and infection in the urinary tract lead to increased calcium absorption in the kidneys, forming kidney stones.
- Inherited disorders of metabolism can alter the composition of urine and increase the risk of stone formation.
- Medications such as diuretics, anti-seizure drugs and some antacids can also play a role in formation of kidney stones.
Types of Kidney Stones
Kidney stones are of different types depending on their composition. These include:
Calcium Stones: They are the most common and are made of calcium oxalate. This is usually caused due to various dietary factors such as eating foods having high oxalate content, such as potato chips, chocolate, spinach, having high quantities of Vitamin D etc. Other medical conditions like intestinal bypass surgery and many metabolic disorders can also increase the concentration of calcium in the urine.
- Uric Acid Stones: This can occur in people who do not drink enough fluids or lose large amounts of fluids. A diet rich in purines, which is an animal protein can increase the acidic level of urine, forming uric acid stones. People suffering from gout and predisposed to certain genetic factors are also at the risk of developing these kidney stones.
- Struvite Stones: These are usually the result of urinary tract infections. These can be large and can cause urinary obstruction.
- Cystine Stones: These are a relatively rare occurrence and are the result of a genetic or hereditary disorder known as cystinuria which causes their kidneys to excrete large amounts of some amino acids.
Symptoms of Kidney Stones
Kidney stones do not show any symptoms until they move into the ureter, which is the tube connecting the kidney and the bladder. At this point, a person experiences the following symptoms:
- Severe pain in the lower back and the sides called renal colic.
- Pain radiating to the groin area
- Blood in the urine (pink, red, or brown urine)
- Pain that occurs in waves and varies in intensity
- Sweating, nausea and vomiting
- Fever and chills
- Frequent and painful urination
- Pain in the testicles or the scrotum in men
How are kidney stones diagnosed?
Diagnosing kidney stones require a complete medical history and a physical examination followed by various tests, such as:
- Blood and urine tests: Presence of excessive levels of calcium or uric acid in the blood and/or in the urine indicates the presence of kidney stones. The urine is also analyzed for the presence of crystals, bacteria, blood and white cells.
- Blood Urea Nitrogen (BUN) tests help determine how well the kidneys are functioning by measuring the level of urea nitrogen in the blood. BUN levels are high when the kidneys are damaged.
- Imaging Tests: CT Scans and X-rays provide images of the kidneys, ureter and the bladder which can be used to detect the presence of kidney stones. However, these should not be conducted in pregnant women as it involves exposure to high doses of radiation. Ultrasound of the kidney is another option
- Analysis of passed stones: The stones passed by the patient in his/her urine is examined in a lab to determine the kind of kidney stones and devising a treatment plan for further prevention and cure.
Treatment for kidney stones
There are different treatment options for kidney stones depending on the type of stones as well as the size.
Small stones which do not result in many symptoms may be treated in the following ways:
- Drinking water: Adequate consumption of liquids can help flush out the smaller kidney stones out of the system.
- Pain relievers such as ibuprofen (Advil, Motrin etc.), acetaminophen (Tylenol) can help relieve mild pain.
- Certain narcotic medications and medications like diuretics are also effective.
- Drugs called alpha-blockers help relax the walls of the ureter, which allows the kidney stones to pass more easily through them out of the body.
Larger stones that do not pass out of the body easily can be treated by the following methods:
- Lithotripsy: Extracorporeal shock wave lithotripsy uses sound waves to create strong vibrations that can break up large stones into smaller pieces which can then be easily expelled from the body. This procedure takes up to an hour to complete and the patient may be sedated before it begins.
- Ureteroscopy: When the stone is close to the bladder, this procedure is performed. It involves inserting a thin tube through the urinary tract and breaking up the stones and removing the smaller fragments through the tube.
- Surgery: A surgical procedure called percutaneous nephrolithotomy, by which kidney stones are removed through a small incision in the person’s back may be performed if the lithotripsy was unsuccessful.
How to prevent the occurrence of kidney stones?
Preventive measures involve certain lifestyle changes such as:
- Drinking adequate water
- Eating lesser oxalate-rich foods such as beets, spinach, spinach, nuts, tea and soy products
- Reducing the intake of salt and animal proteins
- Medications like Vitamin B6 supplements can be taken on the recommendation of the doctor.