symptom of kidney stones : Prevention in patients with recurrent stones

Prevention in patients with recurrent stones — A more extensive work-up is generally recommended for a patient who has had previous stones or who is at higher risk for developing recurrent stones. Special tests are performed to analyze the patient's urine and blood and determine whether underlying conditions may be contributing to stone formation. Examples include too much calcium or uric acid in the urine, which can be treated with specific medications to reduce the incidence of new stone formation.

Radiologic studies, such as an IVP or CT scan, may be performed to search for asymptomatic stones within the urinary tract and to identify anatomic abnormalities that may be responsible for stone formation. If available, the most recently passed stone is analyzed. Depending on its make-up, medications may be prescribed to inhibit the formation of similar stones. Patients with recurrent stones may also benefit from increasing their fluid intake.

SUMMARY

A kidney stone can form when certain substances in the urine are at higher than normal concentrations, although stones can form even if these substance are at normal levels. The substances can form crystals that become attached to the kidney and gradually increase in size, forming a stone.
Eventually, the stone may move down the urinary tract to be expelled in the urine. Or, the stone can remain in the urinary tract, blocking the urine flow and causing pain.
Certain diseases and habits can affect a person's risk for developing kidney stones. These include a past history or family history of kidney stones, certain dietary habits, underlying medical problems, certain medications, and dehydration.
Symptoms are usually produced as a stone passes from the kidney into the ureter (the tube that leads from the kidney to the bladder) (show figure 1). The most common symptom of a kidney stone is pain; other symptoms can include hematuria (blood in the urine), passing small stones, nausea, vomiting, pain with urination, and an urgent feeling of needing to urinate. Many patients with kidney stones have no symptoms.
Clinical symptoms, laboratory tests, and diagnostic x-ray studies may all be used to diagnose a kidney stone. Computed tomography (CT scan) is the preferred diagnostic test in most patients.
During initial treatment, many patients require only pain medication and fluids until the stone is passed. Nonsteroidal antiinflammatory drugs (NSAIDs) may be prescribed for pain and can be given in a vein (IV) or by pill. If the pain is not controlled by an NSAID, narcotics may be prescribed.
Patients are typically instructed to increase their fluid intake to three liters per day, including drinking at night. A severe restriction of dietary calcium intake is not recommended, even for patients with a calcium-based stone, because this can increase the risk of kidney stones.
Stones smaller than 5 mm, and even those up to 7 mm, often pass on their own. Larger stones rarely pass on their own and usually require treatment. Several procedures are available for the treatment, including shockwave lithotripsy, percutaneous nephrolithotomy, and ureterorenoscopy.
Patients with stones that cause no symptoms may be treated, depending upon the size and location of the stone. Other factors are considered in deciding whether to treat the stone, including the patient's occupation (eg, pilot, frequent traveler, local worker) and access to a treatment facility.
Further testing is recommended for patients who have recurrent kidney stones or who is at higher risk for developing recurrent stones. Tests may be performed to determine whether underlying medical conditions are causing the stone formation. Medications may be prescribed to prevent the formation of stones. Patients with recurrent stones also benefit from increasing their fluid intake.

by Glenn M Preminger, MD