Abnormal renal rotation
Updates to Article Attributes
Abnormal renal rotation (renal malrotation) refers to an anatomical variation in the position of the kidneys, in particular to anomalous orientation of the renal hilum. It may occur unilaterally or bilaterally. It is almost always an asymptomatic incidental finding.
Epidemiology
Malrotation is rare, perhaps under reported, and in one autopsy series a prevalence of ~1 in 2000 was reported3. It is more common in males.
Pathology
The exact cause of malrotation of the kidneys is unclear, though it has been hypothesised that malrotation may occur if the ureteric bud inserts into an abnormal region of metanephric mesenchyme. Its association with renal ectopia suggests that certain processes may interupt both normal ascent and rotation.
Gross anatomy
The renal hilum is normally directed anteromedially. The renal hilum is initially oriented anteriorly, but during its ascent from the pelvis the kidney rotates 90 degrees along its longitudinal axis to its more typical orientation.
Anomalies in this process can result in 1-3:
- incomplete rotation or nonrotation (most common): hilum faces anteriorly, ureters are located laterally
- excessive rotation (hyper-rotation): hilum faces posteriorly; renal vessels are located posteriorly
- reversed rotation: hilum faces laterally, renal vessels are located anteriorly, ureter is located laterally
Radiographic appearance
Urography
- malrotation can be demonstrated when the calyces project medially to the renal pelvis
- on CT urography the renal pelvis may be seen projecting anteriorly 4
Development
The exact cause of malrotation of the kidneys is unclear, though it has been hypothesised that malrotation may occur if the ureteric bud inserts into an abnormal region of metanephric mesenchyme. Its association with renal ectopia suggests that certain processes may interrupt both normal ascent and rotation.
Related pathology
- abnormal renal rotation may cause partial ureteropelvic junction (UPJ) obstruction, which can result in increased incidence of urolithiasis and infection
- the malrotated kidney is
proneprone to stasis, also increasing the risk ofcalculus disease.urolithiasis
-<p><strong>Abnormal renal rotation</strong> (<strong>renal malrotation</strong>) refers to an anatomical variation in the position of the <a href="/articles/kidneys">kidneys</a>, in particular to anomalous orientation of the renal hilum. It may occur unilaterally or bilaterally. It is almost always an asymptomatic incidental finding. </p><h4>Epidemiology</h4><p>Malrotation is rare, perhaps under reported, and in one autopsy series a prevalence of ~1 in 2000 was reported <sup>3</sup>. It is more common in males.</p><h4>Pathology</h4><p>The exact cause of malrotation of the kidneys is unclear, though it has been hypothesised that malrotation may occur if the ureteric bud inserts into an abnormal region of metanephric mesenchyme. Its association with <a href="/articles/ectopic-kidney-1">renal ectopia</a> suggests that certain processes may interupt both normal ascent and rotation.</p><h4>Gross anatomy</h4><p>The renal hilum is normally directed anteromedially. The renal hilum is initially oriented anteriorly, but during its ascent from the pelvis the kidney rotates 90 degrees along its longitudinal axis to its more typical orientation.</p><p>Anomalies in this process can result in <sup>1-3</sup>:</p><ul>- +<p><strong>Abnormal renal rotation</strong> (<strong>renal malrotation</strong>) refers to an anatomical variation in the position of the <a href="/articles/kidneys">kidneys</a>, in particular to anomalous orientation of the renal hilum. It may occur unilaterally or bilaterally. It is almost always an asymptomatic incidental finding. </p><h4>Epidemiology</h4><p>Malrotation is rare, perhaps under reported, and in one autopsy series a prevalence of ~1 in 2000 was reported <sup>3</sup>. It is more common in males.</p><h4>Gross anatomy</h4><p>The renal hilum is normally directed anteromedially. The renal hilum is initially oriented anteriorly, but during its ascent from the pelvis the kidney rotates 90 degrees along its longitudinal axis to its more typical orientation.</p><p>Anomalies in this process can result in <sup>1-3</sup>:</p><ul>
-</ul><h4>Related pathology</h4><ul>- +</ul><h4>Development</h4><p>The exact cause of malrotation of the kidneys is unclear, though it has been hypothesised that malrotation may occur if the ureteric bud inserts into an abnormal region of metanephric mesenchyme. Its association with <a href="/articles/ectopic-kidney-1">renal ectopia</a> suggests that certain processes may interrupt both normal ascent and rotation.</p><h4>Related pathology</h4><ul>
-<li>the malrotated kidney is prone to stasis, also increasing the risk of calculus disease.</li>- +<li>the malrotated kidney is prone to stasis, also increasing the risk of urolithiasis</li>
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