Emergency Treatment of an Obstructed, Infected Kidney
The rationale for performing percutaneous nephrostomy (Fig. 3.7) rather than JJ stent insertion (Fig. 3.8) for an infected, obstructed kidney is to reduce the likelihood of septicaemia occurring as a consequence of showering bacteria into the circulation. It is thought that this is more likely to occur with JJ stent insertion than with percutaneous nephrostomy insertion. A discussion of subsequent management of ureteric stones that fail to pass spontaneously, or are too large to do so, is beyond the scope of this book.
Other Non-Stone Causes of Acute Flank Pain
These include pelviureteric junction obstruction (PUJO), which is called ureteropelvic junction obstruction (UPJO) in North America, and infective causes such as acute pyelonephritis, emphysematous pyelonephritis, and xanthogranulomatous pyelonephritis.
Pelviureteric Junction Obstruction
This is a functional impairment of transport of urine from the renal pelvis into the ureter. It may be acquired or congenital. The majority of cases are probably congenital in origin, but do not always present in childhood. Indeed, many present in young adults. The precise cause of the aperistaltic segment of ureter that leads to congenital cases of this condition is not known. Acquired causes of PUJO include stones (the investigation and management of which is discussed above), urothelial tumours (transitional cell carcinoma), and inflammatory and postoperative strictures.
Not infrequently PUJO may present acutely with flank pain, which may be severe enough to mimic a ureteric stone. When imaging (nowadays usually a CT scan) demonstrates hydronephrosis, with a normal-calibre ureter below the pelvi-ureteric junction (PUJ) and no stone (or tumour) is seen, the
3. NONTRAUMATIC RENAL EMERGENCIES 31
FIGURE 3.7. Percutaneous nephrostomy in situ.
32 J. REYNARD
Figure 3.8. JJ stent post insertion.
diagnosis of PUJO becomes likely, and a renogram (e.g., MAG3 scan) should be done to confirm the diagnosis (Fig. 3.9).