Kidney stones are hard deposits that form inside the kidneys when minerals and salts in the urine begin to stick together and create crystals. These stones can be tiny like a grain of sand or grow much larger over time. Some pass out of the body without causing symptoms, while others may block the urinary tract and lead to severe pain or complications.
Kidney stones are a common urinary system problem and can affect people of all ages, although they are seen more often in adults, especially men. Once a person develops a kidney stone, the risk of getting another one in the future becomes higher.
Why do kidney stones form?
Urine naturally contains substances such as calcium, oxalate, uric acid, and other minerals. Normally, these substances dissolve in liquid and leave the body safely. However, when urine becomes too concentrated or certain chemicals rise to high levels, crystals may start forming and gradually turn into stones.
Several factors can increase the risk of kidney stones, including:
• Not drinking enough water
• Diets high in salt, sugar, or animal protein
• Family history of kidney stones
• Obesity and metabolic disorders
• Recurrent urinary tract infections
• Certain medications or high-dose supplements
• Digestive diseases or previous intestinal surgery
Some medical conditions such as gout, diabetes, hyperparathyroidism, or cystinuria can also make stone formation more likely.
Main types of kidney stones
There are several different kinds of kidney stones, and each develops for different reasons:
•
Calcium stones
– the most common type, usually formed from calcium combined with oxalate or phosphate
•
Uric acid stones
– often linked to diets rich in meat and seafood
•
Struvite stones
– associated with urinary tract infections and may grow quickly
•
Cystine stones
– a rare inherited form caused by a genetic condition
Understanding the type of stone is important because it helps guide treatment and prevention.
Symptoms of kidney stones
Small stones may pass unnoticed, but larger stones can become trapped in the urinary tract and cause intense symptoms. Pain usually begins suddenly and may come in waves.
Common symptoms include:
• Sharp pain in the lower back, side, or abdomen
• Pain spreading toward the groin
• Blood in the urine
• Burning or pain during urination
• Frequent urge to urinate
• Nausea and vomiting
• Cloudy or foul-smelling urine
• Fever or chills if infection develops
In some cases, kidney stones may block urine flow and lead to swelling of the kidney, infection, or even kidney damage if left untreated.
How are kidney stones diagnosed?
Doctors use several methods to confirm kidney stones and determine their size and location. Diagnosis may include:
• Urine analysis to check for blood, crystals, or infection
• Blood tests to evaluate kidney function and mineral levels
• Ultrasound examination
• CT scan or X-ray imaging
If a stone passes naturally, doctors may ask the patient to collect it for laboratory analysis.
Treatment
Treatment depends on the size of the stone, its location, and the severity of symptoms. Small stones often pass on their own within several days or weeks. During this time, patients are usually advised to drink plenty of fluids and may receive medication to reduce pain or help relax the urinary tract.
Larger stones or stones causing blockage may require medical procedures such as:
•
Shock wave lithotripsy
(ESWL) – sound waves break the stone into smaller fragments
•
Ureteroscopy
– a thin instrument is passed through the urinary tract to remove or break the stone
•
Percutaneous nephrolithotomy
– used for very large stones through a small incision in the back
Traditional surgery is now less common but may still be needed in rare complicated cases.
Can kidney stones be prevented?
Although kidney stones can recur, many cases are preventable with lifestyle changes. Prevention usually focuses on reducing the concentration of stone-forming substances in urine.
Helpful prevention tips include:
• Drink enough water throughout the day
• Reduce salt and sugary foods
• Avoid excessive animal protein
• Maintain a healthy body weight
• Treat urinary infections promptly
• Follow medical advice regarding supplements and medications