An 18 year old man presents with fevers, right loin pain and dysuria. He has pyuria. You wonder about pyelonephritis or even an infected obstructed kidney so take a look with ultrasound.
Describe and interpret these scans
Image 1: Video taken in longitudinal section of the right kidney and psoas muscle.
A heterogenous hypoechoic mass is seen most obviously lying within the psoas muscle. It can be seen extending into the retroperitoneal space between the kidney and psoas and also involves the renal parenchyma.
Renal abscess with retroperitoneal extension and psoas involvement
Psoas abscess is a rare pathology. It may occur from haematogenous or lymphatic spread, contiguous extension from adjacent infection or occur from traumatic inoculation from penetrating injury. In this case the abscess was extensive involving the renal parenchyma, the retroperitoneal space between the kidney and psoas and the psoas muscle itself. It was not clear whether the origin of the abscess was the kidney with spread to psoas, or the psoas with spread to the kidney. The organism grown both from urine and percutaneous image guided aspiration of the psoas collection grew Escherichia coli perhaps favouring direct extension from the kidney.
- Bell AE. Psoas Abscess. 5-Minute Clinical Consult