Many factors may be involved in the incidence of urinary tract calculi or stone formation (urolithiasis). The exact causes of stone formation are not clear; predisposing conditions include stagnant urine that includes high concentrations of urinary solutes (dissolved substances in a solution), such as calcium oxalate (a salt) and calcium phosphate. Many conditions favor stone formation—for example, infection, dehydration, hypercalcemia, and immobility, among others.

Symptoms vary with the size, location, and causal factors of the calculi. The main symptom is pain, which can be excruciating at times.

Urinary tract calculi frequently demonstrate a sudden onset, with acute pain occurring on the affected side and in the flank; this pain may progress toward the groin as the stone moves downward. The pain may be accompanied by nausea, vomiting, pallor, and diaphoresis. It can be so severe that it causes vasovagal syncope, or a sympathetic response, such as clammy skin. Some patients may complain of groin or bladder pain, resulting from the referred pain of the stone.

1. Assessment and pain management are priorities in nursing care. Hot baths or warm moist packs on the area may offer comfort.
2. If calcium is the main component of urinary calculi, as is the case with many stones, dairy product consumption may increase the tendency of stone formation and reduce oxalate excretion. (Oxalate is commonly present in many stones.) Vitamin D‒enriched foods may also need to be limited for a while, if recommended, so as to inhibit calcium absorption from the GI tract.
3. Unless contraindicated, high fluid intake on an around-the-clock basis may increase hydrostatic pressure and aid in passing of the stones; alternatively, it may dilute the fluid enough to prevent calcium from becoming sufficiently concentrated to precipitate.
4. If the renal stone is composed of uric acid, it may be necessary to limit intake of foods high in purine, such as organ meats, chicken, and sardines. Straining all urine may assist in ascertaining if a stone is passed and determining the treatment options.

1. A 24-hour urine test may be ordered for diagnostic and treatment purposes, including determining the components of the kidney stones. Before starting a 24-hour urine collection for any purpose, patients should first empty their bladder and discard that urine. All the urine within the following 24 hours (including the urine of the last voiding) should be saved and placed on ice, or refrigerated to ensure an accurate test result.
2. Adequate hydration can keep urine dilute and prevent stone formation. Dietary modification may be necessary depending on the components of the stones.
3. Allopurinol (Zyloprim) may be prescribed to reduce blood uric acid level; administer it after meals with a liberal amount of water.
4. Nonsteroidal anti-inflammatory drugs, if ordered, may decrease swelling and facilitate passing of the stone owing to their inhibitory effects on the production of prostaglandin.

Advise patients to report symptoms of acute urinary obstruction, such as pain and inability to void.