What to Do When Urinalysis Results Aren't Crystal Clear

My patient is a 48-year-old woman who has no significant medical history andtakes no medications or supplements. Routine urinalyses consistently show mucusthreads, calcium oxalate and calcium phosphate crystals, and hyaline casts. ThepH is 6, and specific gravity is normal. The remainder of the results are normal.Is further workup required?
-- Joel Tumberello, MD
    PhiladelphiaIf your patient's physical findings (including blood pressure) are normal and there is no laboratoryevidence of either hypercalcemia (which could indicate hyperparathyroidism, for example)or normal anion gap acidemia (which would be suggested by a low serum bicarbonate level),she does not require an extensive workup. A low bicarbonate level could indicate renal tubularacidosis--a rare but occasional cause of calcium phosphate crystals.Further workup would be necessary only if the patient had urinary lithiasis. Without a stone orsymptoms, the urinary findings are not disturbing enough to warrant further evaluation.
-- Gregory Rutecki, MD
    Associate Professor of Medicine
    Northwestern University Medical School
    Chicago