[The area of focal nephritis measured by echography: useful indications in patients with unexplained back pain in comparison with other assessments].

In some patients undergoing an U.S. study of kidney for lumbodynia, it's sometime possible to visualize hypoechoic and areas poorly demarcated without distal acoustic enhancement, localized within the cortex and disrupting the cortico-medullary junction. These findings, called focal nephritis, associated to minimal retention of urine in the bladder, reflect an inflammatory process involving the renal parenchyma, in spite of normal urine analysis. To confirm this theory, 7 patients who presented these findings at US study of kidney underwent renal scintigram with labeled granulocytes. This test revealed the presence of focal bacterial nephritis in the same hypoechoic areas. Therefore US study of kidney combined with renal scintigram is useful to diagnose inflammatory process of the kidney in patients complaining lumbodynia.