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Urinary Bladder - Dilation

Image of dilation in the urinary bladder from a male B6C3F1 mouse in a chronic study
Dilation of the urinary bladder with focal to diffuse flattening of urothelium, from a male B6C3F1 mouse in a chronic study.
Figure 1 of 2
Image of dilation (normal comparison) in the urinary bladder from a male B6C3F1 mouse in a subchronic study
Normal bladder for comparison, from a male B6C3F1 mouse in a subchronic study.
Figure 2 of 2
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Dilation of the urinary bladder is characterized by an overly distended bladder with flattened urothelium ( Figure 1image opens in a pop-up window ). This is a commonly observed change, which can result from a number of etiologies. The most common cause is obstruction. Cases of urinary bladder dilation may be noted where the cause is not apparent or related to chemical administration. The etiology of bladder dilation may be missed when the urethra is not examined. Mouse urologic syndrome in male animals is a frequent cause of obstruction, bladder dilation, inflammation, morbidity, and death. Calculi may also block the outflow of urine, leading to dilation. Although proteinaceous plugs may be observed in the trigone region of the urinary bladder, these plugs usually do not contribute to dilation because in most cases they represent agonal events. Formalin inflation of the urinary bladder is usually recommended, but overinflation and other inflation-related artifacts may occur.


Dilation of the urinary bladder should be diagnosed and given a severity grade. Identification of cause should be considered if dilation is treatment related. If the cause can be identified, it should be diagnosed separately and its relationship to the urinary bladder dilation discussed in the narrative.


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Abstract: http://ebm.sagepub.com/content/120/2/580.abstract

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Abstract: http://www.ilsi.org/publications/urinarysystem.pdf

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Abstract: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1949600/

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Abstract: http://www.ncbi.nlm.nih.gov/pubmed/1666139