A 41 y.o. female with a history of bilateral stone disease resulting in a right nephrectomy in the past. An ultrasound was performed in the renal clinic.
A stone is present in the lower pole (black arrow) on a longitudinal image. Note that there is large shadow (white arrows) not emanating from the stone, without an obvious source.
The renal parenchyma is thin, indicative of chronic damage, and there is some dilatation of the renal pelvis and proximal ureter.
On further longitudinal imaging, there is an echogenic focus within the renal pelvis (while arrow) that is distinct from the lower pole stone (black arrow).
This was confirmed on transverse imaging through the mid kidney.
In the bladder, transverse imaging revealed two separate echogenic structures that appeared connected on longitudinal imaging. While stones can be present in the bladder, they should either be affixed to the wall or lie against the dependent surface.
On further questioning, the patient recalls that there may have been a stent inserted in the left ureter in the past. This would explain the shadow of unapparent source, the additional echogenic focus in the renal pelvis and the findings in the bladder. Stents are often not visible on sonograms due to their variable relationship to the sound beam. The mild dilatation of the renal pelvis and proximal ureter is common with stents unless the bladder is empty. So instead of multiple stones, this patient probably has just one stone. This was confirmed on a subsequent CT scan.
This case illustrates several important points:
sonography often requires interpretation and clinical correlation during the study, which is one reason why nephrologists should be performing renal ultrasounds.
Not every echogenic structure with shadowing is a stone.
The bladder should always be examined.
Comments