Nephrolithiasis: Diagnosis and Treatment
Clinical presentation is highly specific for kidney stones, especially in patients with a history of the condition.
Noncontrast abdominal CT scan is the preferred test to detect stones and urinary tract obstructions. Abdominal x–ray (kidney–ureter–bladder film) will identify many radiopaque stones, but will not detect small or radiolucent stones or urinary tract obstructions.
The intravenous pyelogram has largely been replaced by abdominal CT scan. While the intravenous pyelogram has high sensitivity and specificity for detecting stones, its use is restricted by the risk of contrast reactions and by the fact that evaluation time is very limited when obstruction is present.
Ultrasound is used in patients who should avoid radiation, including pregnant women.
Urinalysis will usually reveal hematuria.
If a stone is passed, it should be sent to the laboratory for analysis.
Immediate urologic attention is necessary for patients who present with fever, renal failure, intractable pain, persistent nausea, or urinary tract infections.
Small (<5 mm) stones will often pass spontaneously, and increased fluid intake will facilitate stone passage. In some cases, tamsulosin (Flomax) or an alpha blocker (eg, terazosin) can also facilitate stone passage. Nonsteroidal anti–inflammatory drugs (NSAIDs) or narcotics may be administered for pain. However, urologists may prefer not to use NSAIDs because of the increased risk of bleeding in the event that the patient should need urteroscopy or shock wave lithotripsy.
About 10% to 20% of stones require surgical removal. Minimally invasive surgical techniques include shock wave lithotripsy, percutaneous nephrostolithotomy, and ureteroscopy. Open renal and ureteral surgery is necessary for stone removal in about 1% of cases.
Extracorporeal shock wave lithotripsy is the treatment of choice for most renal caculi. Percutaneous nephrostolithotomy is as effective as open surgery and is generally indicated for large or complex stones and cystine stones, which are relatively resistant to lithotripsy. Ureterorenoscopy with holmium laser lithotripsy is the treatment of choice for ureteral stones and stones that have failed lithotripsy.
Recurrence is common. Patients who tend to form stones should be instructed in methods of stone prevention, including increased fluid intake, restriction of animal protein and salt, avoidance of oxalate–containing foods (eg, tea, dark greens, chocolate), and consumption of citrates (eg, lemons, citrus juices, potassium citrate supplement). For stones caused by indinavir antiretroviral therapy, hydration and temporary interruption of therapy (1 to 3 days) may decrease recurrence.2
Nephrolithiasis: Nutritional Considerations >>