Nephrolithiasis

Renal calculi are usually asymptomatic until urinary obstruction occurs, causing flank pain, hematuria, infection, nausea, and vomiting. The pain is usually severe and may radiate to the flank, groin, testes, or tip of the penis depending on the level of obstruction. Stones occur three to four times more often in males, are more common in whites than blacks, and usually occur initially between the ages of 30 and 60 years (70%). In a patient who has passed one stone, the likelihood of passing a second stone is ∼15% over 3 years and 50% by 15 years. The average interval between stone events is 9 years. The incidence of stones vary geographically and seasonally, with an increased incidence in the Southeastern USA and in the summer when dehydration is more common.