Urine travels from the kidney to the bladder through tubes called ureters. A ureter stone is a mineral mass in the ureter, which may or may not have originated in the kidney and traveled down into the ureter. A stone begins when particles of minerals in stagnated urine crystallize and form a mass.
If small enough, a stone can disengage and pass through the ureter and out of the body unnoticed. If it is too large, it may lodge in the ureter and obstruct the flow of urine.
Causes and Risk Factors
While the causes of ureter stones are unknown, individuals with a family history are more likely to be at risk. Certain metabolic disorders are also associated with the formation of stones, as are cystic kidney diseases and urinary tract infections.
People who suffer from chronic bowel inflammation may also be susceptible to ureter stones. Intestinal bypass operations or an ostomy surgery (surgically created openings in the body for the discharge of waste) may also contribute to the onset of the condition. In such cases, it may be recommended to limit foods with high oxalate content, including beets, wheat germ, soybean crackers, peanuts, chocolate, sweet potatoes, spinach, rhubarb, okra, or black Indian tea. Substitutions may include red raspberries, strawberries, marmalade, liver, celery, grapes, and grits.
Symptoms of Ureter Stones
If a ureter stone is small, it will cause no symptoms. If it is large enough to become an obstruction, it will block the flow of urine and become extremely painful, accompanied by cramping in the kidney area and lower abdomen, which may later spread to the groin. As the body attempts to expel the stone, urine may appear pink from blood, urination may be more frequent, painful, and cause burning. Accompanying fever and chills indicate the presence of infection.
Diagnosing Ureter Stones
Stones that are small enough not to cause symptoms may appear on an X-ray. Substances that may cause stones to form can be detected with blood and urine tests. A urinary CT scan also may be recommended. In some cases, an intravenous pyelogram (IVP), a diagnostic that uses iodine as a contrast agent with X-rays is used to diagnose ureter stones.
Treating Ureter Stones
Treatments that do not require the use of surgical procedures are always preferable. If stones are small enough, a daily regimen of the patient drinking two to three quarts of water can cause a stone to pass naturally out of the body. Pain medication may be recommended, as well as follow-up medications to control acid or alkali in the urine (the key elements of crystals), or to decrease calcium released into urine by the kidneys and assist in calcium retention in the bones.
When treating infected (struvite) stones, it is important to keep the urine free of bacteria after removal in order to prevent further infection. Antibiotics may be prescribed and regular urinalyses performed.
If stones are causing pain, blocking urine flow, causing infection or growing, surgery is usually necessary. New non-surgical and endoscopic options are available.
Extracorporeal Shock Wave Lithotripsy (ESWL)
Because of its ability to be done on an outpatient basis and short recovery time, if appropriate, Extracorporeal Shock Wave Lithotripsy (ESWL) is most commonly prescribed. There are several kinds of ESWL, some of which use X-rays and some of which use ultrasound. All such treatments break the stones down into particles with shock waves from outside the body, through the skin and tissues, to the stone. The remainder of the particles pass out of the body naturally. If necessary, a stent is placed through the bladder into the ureter to assist in urine flow. This treatment is performed under anesthesia.
Purcutaeneous nephrolithotomy is primarily for the removal of large stones or stones in a location that will not respond to ESWL. In purcutaeneous nephrolithotomy, a small incision is made directly to the kidney, where a device called a nephroscope is used to locate and remove the stone. Larger stones are broken up either with ultrasound or an electrohydraulic device. This procedure requires a hospital stay of several days.
Ureteroscopic Stone Removal
Used only for stones in the mid and lower ureter, ureteroscopic stone removal does not require an incision. Instead, a fiberoptic ureterscope is inserted through the bladder into the ureter to locate the stone, which is either extracted with a cage-like device or shattered with shock waves. A stent may be used to assist in urine flow.