Abstract: PUB616
Not All That Is Black on Kidney Ultrasound Is Hydronephrosis
Session Information
Category: Nephrology Education
- 1302 Fellows and Residents Case Reports
Authors
- Koratala, Abhilash, University of Florida, Gainesville, Florida, United States
- Bhattacharya, Deepti, University of Florida, Gainesville, Florida, United States
Background
As point-of-care renal ultrasound is being increasingly performed by Nephrologists, it is important to have a thorough understanding of renal anatomy and the sonographic appearance of normal kidneys, including normal anatomical variants.
Methods
A 73-year-old woman with hypertension and heart failure has presented with generalized weakness for about 2 weeks leading to a fall at home. She was found to have severe hypercalcemia with a serum calcium of 16 mg/dl and acute kidney injury. CT scan of the chest was obtained to exclude malignancy. In addition to multiple pulmonary nodules, the upper abdominal slices of the scan demonstrated fullness of the left renal pelvis suspicious for hydronephrosis. Renal ultrasound was obtained to evaluate this finding, which demonstrated a large hypoechoic mass just outside the renal sinus but with no distension of the calyces or the ureter [Figure]. This finding was consistent with extrarenal pelvis, which is often confused with hydronephrosis.
Conclusion
An extrarenal pelvis is a normal anatomical variant that is predominantly outside the renal sinus and is larger and more distensible than an intrarenal pelvis that is surrounded by sinus fat. Extrarenal pelvis can easily be misinterpreted as hydronephrosis, especially on a quick bedside exam as it appears as a black mass. Close attention to detail can help differentiate between these two conditions. Hydronephrosis appears as branching, ‘interconnected’ areas of decreased echogenicity that show sonographic evidence of fluid. As the obstruction continues, renal parenchyma becomes compressed with loss of corticomedullary differentiation. On the other hand, extrarenal pelvis is not associated with dilated calyces, parenchymal thinning or hydroureter as in our case. In the figure, a medullary pyramid (line arrow) can be seen just above the central echogenic portion of the kidney suggestive of preserved corticomedullary differentiation and absence of compression.While extrarenal pelvis is asymptomatic in most cases, complications such as infection and stone formation have been reported .