Pyonephrosis
Updates to Article Attributes
Pyonephrosis is a term given to an infection of the kidney with pus in the upper collecting system which can progress to obstruction.
The diagnosis of pyonephrosis is suspected when the clinical symptoms of fever and flank pain are combined with the radiologic evidence of urinary tract obstruction 1.
Radiographic features
Ultrasound
Usually, shows dilatation of the pelvicalyceal system with the following additional features:
- echogenic debris in the collecting system: considered the most reliable sign 4
- fluid-fluid levels within the collecting system
- incomplete ("dirty") shadows of gas in the collecting system may occasionally be seen
CT
The presence of clinical signs of infection with hydronephrosis on CT is considered a more sensitive indicator of pyonephrosis than many of the CT findings alone 6. In addition to features of obstruction, CT may demonstrate:
- thickening of the renal pelvic wall (>2 mm)
- parenchymal or perinephric inflammatory changes
- dilatation and obstruction of the collecting system
- higher than usual attenuation values of the fluid within the renal collecting system
- gas-fluid levels in the intrarenal collecting system
- layering of contrast material above / anterior to the purulent fluid on excretory studies
A caveat to CT evaluation is that it is often difficult to distinguish simple hydronephrosis from pyonephrosis by fluid attenuation measurements.
MRI
MRI may demonstrate features similar to those seen on CT. Some promising preliminary work has been done with both diffusion-weighted imaging and apparent apparent diffusion coefficient maps in an attempt to distinguish hydronephrosis from pyonephrosis, but these techniques require further investigation 4.
Complications
Complications of pyonephrosis may include 7:
- xanthogranulomatous pyelonephritis
- renal abscess
- perinephric abscess
- fistula to pleura, colon and duodenum
Treatment and prognosis
Emergent insertion of a percutaneous nephrostomy to drain the infected collecting system is usually performed after review and close collaboration with a urologist.
See also
-<p><strong>Pyonephrosis </strong>is a term given to an infection of the kidney with pus in the upper collecting system which can progress to obstruction.</p><p>The diagnosis of pyonephrosis is suspected when the clinical symptoms of fever and flank pain are combined with the radiologic evidence of urinary tract obstruction <sup>1</sup>.</p><h4>Radiographic features</h4><h5>Ultrasound</h5><p>Usually, shows <a title="Hydronephrosis" href="/articles/hydronephrosis">dilatation</a> of the pelvicalyceal system with the following additional features:</p><ul>- +<p><strong>Pyonephrosis </strong>is a term given to an infection of the kidney with pus in the upper collecting system which can progress to obstruction.</p><p>The diagnosis of pyonephrosis is suspected when the clinical symptoms of fever and flank pain are combined with the radiologic evidence of urinary tract obstruction <sup>1</sup>.</p><h4>Radiographic features</h4><h5>Ultrasound</h5><p>Usually, shows <a href="/articles/hydronephrosis">dilatation</a> of the pelvicalyceal system with the following additional features:</p><ul>
-</ul><h5>CT</h5><p>The presence of clinical signs of infection with <a title="Hydronephrosis" href="/articles/hydronephrosis">hydronephrosis</a> on CT is considered a more sensitive indicator of pyonephrosis than many of the CT findings alone <sup>6</sup>. In addition to features of obstruction, CT may demonstrate:</p><ul>-<li>thickening of the <a title="Renal pelvis" href="/articles/renal-pelvis">renal pelvic</a> wall (>2 mm)</li>- +</ul><h5>CT</h5><p>The presence of clinical signs of infection with <a href="/articles/hydronephrosis">hydronephrosis</a> on CT is considered a more sensitive indicator of pyonephrosis than many of the CT findings alone <sup>6</sup>. In addition to features of obstruction, CT may demonstrate:</p><ul>
- +<li>thickening of the <a href="/articles/renal-pelvis">renal pelvic</a> wall (>2 mm)</li>
-</ul><p>A caveat to CT evaluation is that it is often difficult to distinguish simple <a title="Hydronephrosis" href="/articles/hydronephrosis">hydronephrosis</a> from pyonephrosis by fluid attenuation measurements.</p><h5>MRI</h5><p>MRI may demonstrate features similar to those seen on CT. Some promising preliminary work has been done with both <a title="Diffusion weighted imaging" href="/articles/diffusion-weighted-imaging-1">diffusion-weighted imaging</a> and apparent <a title="Apparent diffusion coefficient maps" href="/articles/apparent-diffusion-coefficient-1">apparent diffusion coefficient maps</a> in an attempt to distinguish hydronephrosis from pyonephrosis, but these techniques require further investigation <sup>4</sup>.</p><h4>Treatment and prognosis</h4><p>Emergent insertion of a <a href="/articles/percutaneous-nephrostomy">percutaneous nephrostomy</a> to drain the infected collecting system is usually performed after review and close collaboration with a urologist.</p><h4>See also</h4><ul>- +</ul><p>A caveat to CT evaluation is that it is often difficult to distinguish simple <a href="/articles/hydronephrosis">hydronephrosis</a> from pyonephrosis by fluid attenuation measurements.</p><h5>MRI</h5><p>MRI may demonstrate features similar to those seen on CT. Some promising preliminary work has been done with both <a href="/articles/diffusion-weighted-imaging-1">diffusion-weighted imaging</a> and apparent <a href="/articles/apparent-diffusion-coefficient-1">apparent diffusion coefficient maps</a> in an attempt to distinguish hydronephrosis from pyonephrosis, but these techniques require further investigation <sup>4</sup>.</p><h4>Complications </h4><p>Complications of pyonephrosis may include <sup>7</sup>:</p><ul>
- +<li>xanthogranulomatous pyelonephritis</li>
- +<li>renal abscess</li>
- +<li>perinephric abscess</li>
- +<li>fistula to pleura, colon and duodenum</li>
- +</ul><h4>Treatment and prognosis</h4><p>Emergent insertion of a <a href="/articles/percutaneous-nephrostomy">percutaneous nephrostomy</a> to drain the infected collecting system is usually performed after review and close collaboration with a urologist.</p><h4>See also</h4><ul>
References changed:
- 7. Dähnert W. Radiology Review Manual. (2011) <a href="https://books.google.co.uk/books?vid=ISBN9781451118124">ISBN: 9781451118124</a><span class="ref_v4"></span>
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