Urinary Stones (Kidney, Ureter and Bladder)

Urinary stones (calculi) are hardened mineral deposits that form in the kidney or bladder. They originate as microscopic particles and develop into stones over time.
Urinary stones may contain various combinations of chemicals. The most common type of stone contains calcium in combination with either oxalate or phosphate. A less common type of stone is caused by infection in the urinary tract. This type of stone is called a struvite or infection stone. Much less common are the uric acid stone and the rare cystine stone.


Urinary stones usually arise because of the breakdown of a delicate balance. The kidneys must conserve water, but they must excrete materials that have a low solubility. These two opposing requirements must be balanced during adaptation to diet, climate, and activity. The problem is mitigated to some extent by the fact that urine contains substances that inhibit crystallization of calcium salts and others that bind calcium in soluble complexes. These protective mechanisms are less than perfect. When the urine becomes supersaturated with insoluble materials, because excretion rates are excessive and/or because water conservation is extreme, crystals form and may grow and aggregate to form a stone. The same occurs in the bladder due to inadequate bladder emptying from a poorly functioning bladder or bladder outlet obstruction.


The first symptom of a kidney stone is extreme pain. The pain often begins suddenly when a stone moves in the urinary tract, causing irritation or blockage. Typically, a person feels a sharp, cramping pain the back and side in the area of the kidney or in the lower abdomen. Sometimes nausea and vomiting occur with this pain. Later, the pain may spread to the groin.

If the stone is too large to pass easily, the pain continues as the muscles in the wall of the tiny ureter try to squeeze the stone along into the bladder. As a stone grows or moves, blood may be found in the urine. As the stone moves down the ureter closer to the bladder, a person may feel the need to urinate more often or feel a burning sensation during urination.

Bladder stone can be infected and resulted in interruption to your urine streams and also the need to urinate more often or feel a burning sensation during urination.
If fever and chills accompany any of these symptoms, an infection may be present. In this case, a doctor should be contacted immediately.


The urologist will order laboratory tests, including urine and blood tests. If a stone has been removed, or you have passed a stone and saved it, the lab can analyse the stone to determine its composition.
X-ray tests such as CT scan and ultrasound is used to diagnose urinary stones and to rule out other serious medical or surgical conditions that mimics renal colic. Your doctor might ask you to undertake a battery of tests to confirm that the stone disease is not the result of any primary disease.

Treatment options


In asymptomatic patients a wait-and-see course may be recommended by your doctor. Many stones will become symptomatic and produce acute renal colic while traveling down the ureter some time in the future. The stones may enlarge and then become more problematic and difficult to treat.

Pain control

The severe pain of renal colic needs to be controlled by potent pain killers. Don't expect an aspirin to do the trick. Get yourself to a doctor or an emergency room. Also, the pain may be caused by some other problem needing immediate attention.

Expulsive therapy

In recent years, medical expulsion therapy can be used to assist the passage of stones in the lower end of the ureter. Unfortunately certain features of the urinary stone and ureter could impede the success of oral therapy. It is important that a follow up imaging is performed to ensure the stone has passed.

Surgical option:

ESWL (Extracorporeal Shock Wave Lithotripsy)

ESWL involves shattering a stone with a shock wave produced outside the human body. There are several methods for producing an acoustical or ultrasonic "big bang" which is then focused from outside into the kidney or ureter and the stone. This is not suitable to treat bladder stones. Sometimes, a ureteric stent in inserted prior to ESWL if you have been experiencing significant renal colic.

Endoscopic removal and/or laser lithotripsy

Ureteroscope is a long thin telescope that is introduced into your urinary tract via urethra/bladder. A small instrument port allows for introduction of micro-baskets and laser fibres to manipulate and fragment stone and retrieve stone fragments. Depending on the difficulty of surgery, a urinary stent may be inserted at the end of the procedure and this can be removed at a later date.

Percutaneous nepholithotomy (PCNL)

PCNL is the preferred technique for treating larger stones (over 1.5 cm in diameter) within the kidney. It involves keyhole surgery performed through a 1 cm incision in the skin overlying the kidney. Depending on the difficulty of surgery, a urinary stent may be inserted at the end of the procedure and this can be removed at a later date.

Meet Professor Chung

Associate Professor Chung is a urological surgeon specialising in andrology, microsurgical, and urological prosthetic surgery.