What is the cause of left sided hydronephrosis?
Pelviureteric junction (PUJ) obstruction.
In the above study, what additional protocol would have helped in knowing whether it is complete or partial obstruction?
Administration of furosemide (0.5-1mg/kg) during the study, may provoke excretion of contrast through left ureter in partial obstruction. However, complete obstruction would not have any passage of contrast even after provocation.
In the above case, if calyces were dilated with normal pelvis, what would have been possible diagnosis?
Congenital megacalycosis.
What would be possible causes of a ballooned renal pelvis with essentially normal calyceal system?
Extrarenal pelvis is a common variant.
When found incidentally in an adult what are some of the underlying aetiologies which should be considered?
Congenital PUJ obstruction often remains asymptomatic, and as such is a likely diagnosis even in adults. Aberrant vessels, kinks or a band (e.g. retroperitoneal fibrosis) may cause extrinsic PUJ anomaly. Tumours or even infection (e.g. TB) at the PUJ can also cause localized obstruction.
If while performing a plain film IVP a linear filling defect is seen at the pelviureteric junction what is the most likely cause? What simple technique can confirm this?
Extrinsic vascular compression is common, with or without renal pelvis prominence. Sometimes a prone film helps as the extrinsic compression is relieved.
Left sided hydronephrosis is seen with dilated and ballooned out left renal pelvis. Left pelviureteric junction is markedly narrowed with probably delayed contrast excretion into left ureter.