Kidney Stones

A kidney stone, also called a renal calculus, is a hard, crystal-like mass that has formed in the urine collection system of the kidney, the renal pelvis. It is made of substances dissolved or suspended in urine that form crystals on the inner surfaces of the kidney. Over time, these crystals form a stone. Normally, urine contains chemicals that prevent or inhibit the crystals from forming. When these inhibitors don’t work, stones form. If the stones are small, they will travel through the urinary tract and pass out of the body in the urine without causing symptoms. The most common type of kidney stone is made of calcium in combination with either oxalate or phosphate. These chemicals are part of a person's normal diet and are found in bones and muscles. Less common types of stones are those caused by infection in the urinary tract, called struvite or infection stones, and stones made of uric acid.

Causes

Doctors do not always know what causes a stone to form. A person with a family history of kidney stones may be more likely to develop them. Certain conditions are also linked to kidney stones, including a urinary tract infection, gout and metabolic disorders such as hyperparathyroidism. Taking too much vitamin D or using diuretics can cause kidney stones to form.

Symptoms

Symptoms occur when the kidney stone enters the ureter on its trip from the kidney to the bladder. Usually the first symptom of a kidney stone is extreme pain. It begins suddenly when a stone blocks or irritates the ureter and causes spasms. A person may feel a sharp, cramping pain in the back near the affected kidney or in the lower abdomen. Nausea and vomiting may also be present. Pain may radiate to the groin.

If the stone is not passed promptly, pain will continue as the muscles of the ureter try to push it out. As the stone passes, you may notice blood in your urine. As the ureters move the stone closer to the bladder, you may feel the urge to urinate more frequently or you may feel a burning sensation during urination.

If you have fever or chills with these symptoms, you may have an infection. In this case, call your doctor right away.

Treatment

In most cases, kidney stones are small enough to pass through the ureter without being noticed. The best way to help a stone pass is to drink plenty of water, about 12 to 16 cups a day. If you need to, you can take a pain medication to help relieve your symptoms.

When you do urinate, catch the urine in a cup or pass it through a strainer used only for this purpose to catch the stone. Your doctor will probably want you to save the passed stone for testing.

Surgery may be needed to remove a kidney stone if the stone:

• Does not pass after a reasonable period and causes constant pain

• Is too large to pass on its own or is caught in a difficult place

• Blocks the flow of urine

• Causes ongoing urinary tract infections

• Damages kidney tissue or causes constant bleeding

• Has grown larger, as seen by an X-ray exam

Self-Care Steps for Kidney Stones

• Drink plenty of water.

• Take a pain medication, such as acetaminophen, to relieve pain.

• Call your doctor if pain continues, you have visible blood in your urine or you have been unable to urinate.

Preventive Care for Kidney Stones

If you have had a kidney stone, you are likely to form another, so prevention is important.

• Follow the advice of your doctor regarding what type of dietary modification you need to make. Dietary restrictions are based on the type of kidney stone you have.

• If your doctor prescribes medication, take it as directed.