Ask PERS

Kidney stones are hard mineral deposits that form inside the kidneys. 

They develop when certain substances in the urine—such as calcium, oxalate, or uric acid—become concentrated and crystallize. Over time, these crystals can grow into stones.

Kidney stones can remain in the kidney or move into the ureter, the tube that connects the kidney to the bladder. When this happens, they may cause pain or blockage of urine flow.

Kidney stones form when the urine contains high levels of minerals that can crystallize. Several factors increase the risk of stone formation, including:

Often, more than one factor contributes to stone formation.

Kidney stones may cause symptoms when they move or block the urinary tract. Common symptoms include:

• Severe pain in the side or lower back
• Pain that radiates to the lower abdomen or groin
• Blood in the urine
• Nausea or vomiting
• Painful urination
• Frequent urge to urinate

Small stones may sometimes pass without causing symptoms.

Yes, many small kidney stones can pass on their own through the urine. Stones that are smaller than about 5 millimeters often pass spontaneously.

Your doctor may recommend:

• Drinking plenty of fluids
• Pain medications
• Medicines that help relax the ureter

However, larger stones may require medical or surgical treatment.

Kidney stone pain is often described as one of the most severe types of pain. It usually occurs when a stone blocks urine flow in the ureter.

The pain often comes in waves and may:

• Start in the flank or back
• Move toward the abdomen or groin
• Be associated with nausea or vomiting

Prompt medical evaluation is recommended if severe pain occurs.

Doctors diagnose kidney stones through a combination of:

• Medical history and physical examination
• Urine tests
• Blood tests
• Imaging studies

Imaging tests are important to confirm the presence, size, and location of the stone.

Common tests include:

• Urinalysis – Detects blood, infection, or crystals in the urine.
• Blood tests – Measure kidney function and mineral levels.
• Imaging studies – CT scan, Ultrasound, X-ray (in some cases).

In patients with recurrent stones, a 24-hour urine test may be recommended to evaluate metabolic causes.

A CT scan is the most accurate test for detecting kidney stones. It can show the exact size and location of the stone and determine whether it is causing obstruction.

However, ultrasound may be used instead in some situations, such as in pregnant patients or when radiation exposure should be minimized.

Yes, ultrasound can detect many kidney stones, particularly those located in the kidney. It is a safe and widely available test that does not use radiation.

However, ultrasound may miss smaller stones or stones located in the ureter. In these cases, a CT scan may be needed for a more accurate diagnosis.

Treatment depends on the size, location, and symptoms of the stone.

• Stones less than 5 mm often pass on their own
• Stones 5–10 mm may pass but sometimes require treatment
• Stones larger than 10 mm usually require intervention

Surgery may also be needed if the stone causes infection, severe pain, or obstruction of urine flow.

Treatment options depend on the size and location of the stone.

• Medical therapy – Pain medications, medicines to help pass the stone
• Ureteroscopy with laser lithotripsy
• Shock wave lithotripsy (SWL)
• Percutaneous nephrolithotomy (PCNL)

Your urologist will recommend the most appropriate treatment.

Some kidney stones, particularly uric acid stones, can be dissolved using medications that alkalinize the urine.

However, most stones—especially calcium stones—cannot be dissolved and may require other treatments if they do not pass naturally.

Ureteroscopy is a minimally invasive procedure used to treat stones in the ureter or kidney.

A thin telescope called a ureteroscope is passed through the natural urinary passage without any incision. A laser is often used to break the stone into small fragments that can be removed or passed naturally.

Laser lithotripsy is commonly used during ureteroscopy to break kidney stones into small pieces.

A laser fiber is placed directly against the stone and breaks it into fine fragments that can be removed or passed in the urine.

This technique is highly effective and widely used in modern endourology.

Percutaneous nephrolithotomy is a minimally invasive surgery used to remove large kidney stones.

In this procedure:

• A small incision is made in the back
• A narrow tract is created directly into the kidney
• Instruments are used to break and remove the stone

PCNL is often recommended for stones larger than 2 centimeters.

The duration of surgery depends on the procedure being performed.

• Ureteroscopy: 30–90 minutes
• Shock wave lithotripsy: 45–60 minutes
• PCNL: 1–3 hours

Most procedures are performed under anesthesia.

Recovery time depends on the type of procedure.

• Ureteroscopy: return to normal activities in a few days
• Shock wave lithotripsy: minimal downtime
• PCNL: hospital stay of 1–2 days

Your doctor will give specific instructions for recovery.

Yes, kidney stones can recur. About 50% of patients may develop another stone within 5–10 years if preventive measures are not taken.

Proper evaluation and preventive strategies can significantly reduce recurrence.

Preventive measures include:

• Drinking at least 2–3 liters of water per day
• Reducing salt intake
• Maintaining a balanced diet
• Limiting excessive animal protein
• Following medical advice based on stone composition

Patients with recurrent stones may benefit from a metabolic evaluation, including a 24-hour urine test.