Answers to Case 1-1-6
1. Figure 1-1-6.1 is part of a limited IVU series, showing a control (a), 15-min (b)
and 4-h postmicturition (c) fi lm. On the control fi lm, there is a small radio-opacity
seen near the left VUJ, which is causing ureteric obstruction with a bright,
delayed nephrogram on the 15-min fi lm. By the 4-h fi lm, the level of obstruction
(i.e. the VUJ) has been demonstrated.
2. The advantages of the IVU for acute colic is that it is widely available at all hours
and the images are easier to interpret as the collecting system anatomy is better
demonstrated. Follow-up imaging, where a stone is visible, can be with a KUB
radiograph. The modern alternative is a non contrast helical CT KUB. This has a
superior accuracy, and iodinated contrast is not required. It is also very quick and
radiolucent stones (e.g. uric acid stones) are also visualised. Furthermore, other
intra-abdominal pathology may be diagnosed on CT. The radiation dose of an
IVU is slightly lower than most CT KUBs. Neither is suitable as fi rst line investigations
for children or during pregnancy, for which an ultrasound and KUB are
used, supplemented by MRU (magnetic resonance urogram) for the latter.
3. Immediate management is tailored according to clinical status. Pain control with
a non-steroidal anti-infl ammatory drug and hydration are paramount. Medical
expulsive therapy with an alpha-blockers e.g. tamsulosin is recommended to
expedite ureteric stone passage. Those with signs of infection may require renal
de-obstruction (either a nephrostomy or stent placement). A patient with a single
kidney, bilateral obstruction or poor renal function may also require de-obstruction.
Later management is dependent on the size and site of the ureteric calculus,
and also its likely composition. Large (>6–7 mm) ureteric calculi are unlikely to
pass spontaneously and may require lithotripsy or ureteroscopic extraction.
Follow-up of stone progress is generally best done with KUB (if the stone is
opaque), unless it is located, as in this case, at the VUJ in which case bladder
ultrasound may be more suitable.