Elderly male presents with increasing confusion, generally unwell.
He is found to be in acute renal failure.
The first image shows a very distended bladder with a large prostate - this is urinary retention.
The trabeculation of the bladder wall means that although this may have acutely worsened there is an element of chronic bladder hypertrophy here.
The next two images show severe hydronephrosis with severe distension of the collecting system, blunting of the calyces and thinning of the renal cortex.
The final image is taken to confirm passage of the urinary catheter prior to drainage of the bladder. The ureteric dilation is seen posterior to the bladder.
Acute renal failure - the ultrasound approach is to determine whether this is prerenal, renal or post renal.
Flattened IVC and empty bladder in keeping with intravascular depletion and reduced urine production.
There may be an abnormal renal appearance ranging from polycystic kidneys, to bulky echogenic kidneys with interstitial disease / acute nephritis or varying aetiology, to small chronically diseased kidneys.
Obstructive uropathy is manifest by a distended bladder, ureteric distension (as is seen in this case) and hydronephrosis.
Occasionally there is bilateral ureteric obstruction (as in tumour infiltration or bilateral calculi) and the bladder is not full.
It is also important to mention that the lack of hydronephrosis does not absolutely exclude ureteric obstruction. With acute obstruction there may not have been time for hydronephrosis to form. Also when there are multiple causes (including prerenal / renal) urine production will be decreased and hydronephrosis may be less evident despite coexistent obstruction.