Answer: B, C, D and E) Obstructive nephropathy secondary to an enlarged prostate, Progressive chronic kidney disease secondary to yet unidentified chronic medical illness, RPGN AND Pre-renal injury

B, C and E sit highest on differential. It’s difficult at this point to determine the chronicity of the problem given that we have no baseline values; however,

Given his age, obstructive uropathy secondary to an enlarged prostate is high on our DDx. Normal urinary output does NOT rule out obstruction. In fact sensation of polyuria is sometimes reported due to bladder distension and overflow leading to urinary frequency.

Given N/V and decrease appetite it is likely that a pre-renal injury is at least in part contributing to the renal insufficiency. It is unclear whether the progressive renal injury led to the N/V and decreased intake in the first place.

Answer: B and C) Dilated renal pelvis and calyces AND Slightly small kidneys with a relatively hyperechoic renal cortex when compared to the liver/spleen

As the acuity of his Cr rise is unknown, this could be the culmination of chronic progressive kidney disease secondary to an unknown chronic medical condition (eg. DM or HTN). In this case the kidneys often appear smaller than normal and hyperechoic. Normally, the renal cortex is similar in echotexture to the liver or spleen. In chronic kidney disease, the cortex often looks thinned out and hyperechoic relative to the other abdominal organs. Note, however, that this is a more nuanced finding and relatively non-specific, so should not be relied upon in isolation in a POCUS exam.

In a man over the age of 50, a diagnosis of bilateral obstructive nephropathy secondary to prostatism must also be considered given the prevalence of BPH.

A stone in the cortex would not cause urinary obstruction. If a stone were lodged at the UPJ it could cause urinary obstruction, but this would be an atypical presentation in this case given the lack of significant abdominal/flank discomfort. Furthermore, and a significant kidney injury (as we have here) secondary to obstruction would generally imply bilateral involvement, which is unusual for kidney stones.

Answer: B) Obstructive nephropathy with evidence of bilateral moderate hydronephrosis and proximal hydroureter

In these images, the normally hyperechoic central collecting system has been replaced by an anechoic pocket that extends into the calyces with finger-like projections into the medulla. These anechoic spaces are contiguous, and exit the kidney towards the midline via a dilated renal pelvis. This is consistent with moderate hydronephrosis.

In contrast, renal cysts are most commonly seen arising from the cortex rather than the renal pelvis. PCKD, however, can result in a multi-cystic mass that replaces any recognizable renal anatomy. Importantly, cysts do not communicate. In the preceding images, the calyceal dilatation initially appears cystic, however as the sonologist fans through the kidney, communication with the pelvis and proximal ureter are clearly demonstrated. This is a key element to renal POCUS when searching for hydronephrosis.

Answer: A) Ureters

The ureters insert posterior to the bladder, as demonstrated here. They are generally not visible given their diminutive size and artifact from surrounding bowel. In this case, however, they are easily seen because of a distal obstruction resulting in significant dilatation.

Colour doppler is present on the image on the right, in which the bladder is now seen as in a longitudinal view. There is colour flow deep to the structure of interest, but clearly no colour seen inside, thereby making it very unlikely to be vascular.

The vas deferens does sit deep to the bladder but it does not appear as a tubular structure