Serum calcium, phosphorous, bicarbonate, magnesium, and uric acid

Serum calcium, phosphorous, bicarbonate, magnesium, and uric acid levels are effective in screening for hypercalcemia- and hypocalcemia-associated calculi (discussed earlier), Galunisertib ic50 hyperuricemia, HHRH, Bartter syndrome, dRTA, and FHHNC. Unlike in adults, primary hyperparathyroidism is rare in children and an intact parathyroid hormone level is not an essential part of the initial evaluation unless there is evidence of hypercalcemia

and hypophosphatemia. A 25-hydroxyvitamin D level should be evaluated in all patients with hypercalcemia. A spot urine beta-2 microglobulin (low-molecular-weight protein) is a useful screening test for Dent disease and should be considered in men and possibly carrier women if there are recurrent calcium-based calculi in the setting of proteinuria or a family history of renal failure, focal segmental glomerulosclerosis, or recurrent calculi. A 24-hour urine collection should be analyzed for calcium, oxalate, uric acid, sodium, citrate, creatinine levels, volume, pH, and cystine (cyanide-nitroprusside screening test). Results must be evaluated with respect to weight, body surface area, and creatinine level

to be properly interpreted in children. Urine creatinine excretion (normal 15–25 mg/kg/d) is useful in assessing the adequacy of the urine collection. Supersaturations for calcium oxalate, calcium phosphate, and uric acid can be calculated selleck chemicals llc from computer models based on the results of the urine collection. There is ongoing controversy as to whether a single 24-hour urine collection at the time of diagnosis is sufficient for proper evaluation38 or whether 2 separate collections yield a greater number of specific diagnoses.39 Several commercial companies, including Litholink,

Mission, Dianon, and Urocor offer these 24-hour urine stone chemistry profiles. Although less precise, when children are not yet trained to use toilet, the evaluation may be performed by measuring the ratio of calcium, uric acid, citrate, and oxalate levels to creatinine level in a random urine sample. Repeat urine testing should be performed several weeks to months after a change in diet or after the initiation of a medication. Microscopic urinalysis P-type ATPase for crystalluria is generally not diagnostic unless hexagonal crystals (cystine) or coffin lid–shaped triple phosphate crystals (struvite) are observed. The first goal of medical management should be directed toward control of the acute complications. Pain associated with the passage of a stone is often severe and should be treated promptly with narcotic analgesics (morphine sulfate) and/or nonsteroidal antiinflammatory drugs (Ketorolac). If the patient is vomiting or unable to drink, parenteral hydration should be used to maintain a high urine flow rate. In the absence of oligoanuric renal failure or a complete obstruction, an intravenous infusion rate of 1.5 to 2 times maintenance is recommended.

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