An elderly man presented with hypotension and collapse. A diagnosis of urosepsis was made and an ultrasound requested to exclude an obstructed, infected kidney. He denied any previous renal history.
There was a moderate amount of ascites. Neither the left nor right kidneys could be identified in the usual position, so the pelvis was examined which revealed a horseshoe kidney with dilation of the right collecting system.
Causes of inability to find a kidney include nephrectomy, congenital aplasia or hypoplasia or ectopic location (such as a pelvic, crossed ectopic or horseshoe kidney). The kidneys in chronic renal failure are often shrunken and hyperechoic with loss of the cortico-medullary differentiation, making them difficult to identify.
Right Upper Quadrant
Free fluid is seen but there is no identifiable kidney