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Kidney Stones

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of kidney stones.

Alternative Names

Calcium Stones; Extracoporeal Shock Wave Lithotripsy; Lithotripsy; Nephrolithiasis; Oxalates; Uric Acid

Treatment

When tests have established the presence of a kidney stone, the next step is to determine treatment. The patient should be admitted to the emergency room if vomiting is severe, if fever is present, or if symptoms indicate an infection. X-rays are usually warranted at that time to determine the presence of a stone.

Strong opioid painkillers such as meperidine (Demerol) are often required for a severe kidney stone attack, although physicians will usually not administer them until the presence of a kidney stone has been confirmed on the x-ray. In some cases, administration of powerful nonsteroidal anti-inflammatory drugs (NSAIDs) may be as effective as opioids and they have fewer side effects. They do take longer to have an effect, however.

General Guidelines for Follow-up Treatment

Watchful Waiting. In about 85% of patients, the kidney stones are small enough that they pass during normal urination, usually within two to three days. In some cases, a stone may take weeks to months to pass, although pain usually subsides well before that. In one study, the likelihood of a stone passing spontaneously ranged from 87% for stones 1 mm in diameter (about 4/100 of an inch) to only 25% for stones larger than 9 mm (about a third of an inch). Stones in the lower ureter were also more likely to pass on their own (75%) than those in the upper ureter (48%).

The patient should drink plenty of water (two to three quarts a day) to help move the stone along, and take painkillers as needed. The doctor usually provides a collection kit with a filter and asks the patient to save any passed stones for testing.

If the stone has not passed in two to three days, then additional treatments are warranted. In some severe cases, hospitalization may be necessary.

Indications for Lithotripsy or Surgery. Specific procedures vary depending on the size of the stone or complexity of the situation. Noninvasive procedures have largely replaced invasive surgery and are proving to be very beneficial in eliminating stones.

  • Extracorporeal shock wave lithotripsy is used for small stones (less than one centimeter, or slightly less than half an inch) that do not pass spontaneously and occur in the upper part of the ureter. One study indicated lithotripsy might even be safe and effective for patients whose stones are associated with malformed kidneys, although such patients are at higher risk for stone recurrence and should be carefully monitored.
  • For small stones that are lodged in the lower part of the ureter, ureteroscopy or shock wave lithotripsy are the procedures of choice.
  • For larger stones, ureteroscopy, percutaneous nephrolithotomy, and shock wave lithotripsy are all potentially useful, depending on location, abnormalities, and other considerations.
  • In some complicated cases, standard open surgical procedures (called nephrolithotomy) may be required.

Preventing Recurrence

Dietary Considerations. People with kidney stones appear to be more sensitive to certain foods than people who do not form kidney stones and need to make specific changes in their diet. They should work with their physicians to develop a dietary plan that fits their individual situation. Drinking plenty of fluids is important for preventing recurrence of any kidney stone.

Indications for Drug Treatments. If dietary measures fail then drug treatments may be helpful. A number of drugs are available to prevent recurrences of calcium oxalate and other stones. Allopurinol, thiazide, potassium citrate, and potassium-magnesium citrate have all been shown to inhibit stone formation. In addition, drug treatments can sometimes also help prevent other complications related to stones, such as osteoporosis.

Correcting Underlying Conditions Known to Cause Kidney Stones. It is also important to treat and correct, if possible, any underlying disorder that may be causing stones to form. Such disorders include distal renal tubular acidosis, hyperthyroidism, sarcoidosis, and certain cancers. To prevent calcium stones that form in hyperparathyroid patients, a surgeon may remove the affected parathyroid gland (located in the neck). In most cases, only one of the glands is enlarged. Removing it ends the patient's problem with kidney stones.

Treatment by Stone Type

Stone Type

Diet and Lifestyle

Medications

Procedures

Calcium Oxalate

Plenty of fluids. (Choose water, lemon juice. Avoid grapefruit, apple, and cranberry juice.)

Restrict protein and salt.

Increase fiber.

Restrict fats (particularly with short bowel syndrome).

Normal calcium intake balanced with potassium- and phosphate-rich foods.

Restrict calcium only in people who have genetic abnormalities that cause high intestinal absorption of calcium.

Restrict foods high in oxalates only in patients with rare intestinal conditions that cause hyperoxaluria.

Diuretics, Citrate salts, phosphates, cholestyramine.

Lithotripsy, uteroscopy, percutaneous nephrolithotomy, open surgery.

Uric Acid

Plenty of fluids (Choose water, blackcurrent juice. Avoid cranberry juice.).

Increase calcium intake (be sure well balanced with potassium and phosphates).

Reduce protein and other foods with high-purine content.

Potassium citrate, sodium bicarbonate, allopurinol.

Lithotripsy, uteroscopy, percutaneous nephrolithotomy, open surgery.

Struvite stones

Plenty of fluids (water, cranberry juice).

Reduce proteins.

Antibiotics to eliminate any infection. Acetohydroxamic acid (AHA) may be helpful in combination with antibiotics. In some cases, organic acids administered through urinary tract.

May respond poorly to most lithotripsy procedures and require open surgery. (Newer procedures may be helpful.)

Cystine stones.

Very high fluid intake (four quarts a day).

Restrict protein.

Alkalizing agents (such as bicarbonate). Sometimes d-penicillamine, tiopronine, or captopril useful for lowering cystine levels.

May respond poorly to most lithotripsy procedures and require open surgery. (Newer procedures may be helpful.)

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