American Medical Association Family Medical Guide - American Medical Association [540]
Tiny stones seldom cause problems because they are easily carried in the ureters and urethra and passed in urine. Any stone with a diameter of about 1/5 inch or more, however, can cause severe pain if it enters the ureter. Passage of a kidney stone is a frequent cause of brief hospital admissions for pain control and administration of fluids.
Kidney stones run in families. Men are more susceptible to developing kidney stones than women, and the risk increases after age 30. Kidney stones occur more frequently in people who live in hot climates because of increased loss of body water in very warm weather. Also, unless their fluid intake is substantial, people in hot climates produce a smaller, more concentrated volume of urine, which contains a higher proportion of stone-forming material. In rare cases, children develop a type of kidney stone caused by a chemical abnormality in the blood.
Kidney stone
A kidney stone is a hardened accumulation of mineral salts or other substances that forms in a kidney. A stone that is smaller than 1/5 inch in diameter can usually pass through a ureter and urethra without difficulty. However, a larger stone can become lodged in the ureter, blocking the flow of urine and causing severe pain.
Most kidney stones are eventually passed in the urine. An occasional stone may get stuck in a ureter and block the flow of urine on one side; surgery may be required to remove the stone because of the risk of severe kidney infection and kidney damage.
Symptoms
If a kidney stone is too large to pass from the kidney into the ureter, it may not cause any symptoms or may cause only occasional pain as small pieces break off and are carried down the ureter. The most common symptom of a kidney stone is renal colic, a severe, stabbing pain that tends to come in waves, often a few minutes apart. Renal colic can develop when a stone passes from a kidney down one of the ureters, blocking the flow of urine. The pain will subside if the stone moves into the bladder. The pain usually occurs on one side of the body, but if you have stones in both kidneys, a subsequent attack of pain can occur on the other side.
Pain from a kidney stone usually occurs first in the back, just below the ribs on one side of the spinal column. Over the next few hours or days, the pain may follow the course of the stone as it travels through the ureter—from the back around to the front of the body and down toward the groin. In men, the pain may radiate to the testicles; in women, the pain may radiate to the labia. You may feel nauseated, and notice traces of blood in your urine. After the stone reaches the bladder, it usually passes more easily through the remainder of the urinary tract.
Site of kidney stone pain
Pain from kidney stones
A kidney stone can cause severe pain as it travels from the kidney to the bladder. This process can take several days. The location of the pain often indicates the position of the stone.
Diagnosis
If you have renal colic, your doctor will probably order blood and urine tests and a CT scan (see page 112) or ultrasound (see page 111) to find the cause of your symptoms, locate any stones, and help determine if treatment is necessary.
A 24-hour urine test can determine if your body excretes too much of a specific mineral salt or other stone-forming substance or if your urine does not contain enough of a specific body chemical that inhibits stone formation. Half of all people who develop a kidney stone will develop a second stone within 10 years.
Treatment
If you have symptoms of a kidney stone, your doctor will recommend drinking large quantities of water (at least eight large glasses of water every day) to help flush any stones through your urinary tract and to help prevent more stones from forming by keeping your urine diluted. Your doctor will prescribe pain relievers