[Metabolic evaluation at the time of the first renal lithiasis episode]

There are little doubts about the need of studying thoroughly every patient with recurrent renal lithiasis. However, the behavior to be followed after the first renal calculi remains controversial. For that reason, we decided to answer a series of questions after which, we formulate our own criteria: Which is the recurrence rate after the first calculi? Has a patient with recurrent lithiasis, the same metabolic disarrangement as a patient who has his first episode? Is the family history of both kidney stone patients the same? Which is the morbility of both groups? We answered these questions with data drawn from 200 of our patients (100 with first episode and 100 with recurrent lithiasis) and a review of the medical literature. The patients with their first episode of lithiasis correspond to the same population of patients with recurrent episodes, but they are detected at different moments of their stone disease. This was concluded since both groups of patients had the same metabolic disarrangement with predominance of hypercalciuria and alteration in uric acid metabolism. Furthermore, the family history was practically the same in both groups (39% in first episode, 41% in recurrent lithiasis) and so was the morbility. Therefore, we propose the following conduct: 1. every patient with renal lithiasis should be studied starting at the first episode, from the urological and metabolic point of view; 2. the initial metabolic studies have to be as extensive as possible in order to aim for specific treatment from the start in order to prevent a recurrence, and in the case of hypercalciuric patients to prevent secondary osteopenia.