Hydronephrosis
Hydronephrosis is a relatively common incidental finding at necropsy and occurs in a variety of strains and stocks of rats. In some strains, there is a hereditary basis for the disorder.
For example, in the Brown Norway rat, hydronephrosis appears to be an autosomal polygenetic disorder, with incomplete penetrance. In the Gunn rat, it is apparently inherited as a dominant gene and may be lethal when present in the homozygous state. In studies of hydronephrosis in outbred Sprague-Dawley rats, it was concluded that the condition is a highly heritable trait, probably involving more than 1 gene. Spontaneous hydronephrosis, particularly of the right kidney, is a well-recognized abnormality, especially in male rats. It has been proposed that the lesion in males may be due to the passage of the internal spermatic vessels across the ureter, resulting in mechanical obstruction to outflow and subsequent hydronephrosis of the affected kidney. However, sectioning of the right spermatic vessels in young male Wistar-derived rats failed to reduce the incidence of hydronephrosis, compared with control animals.At necropsy, there may be varying degrees of involvement. In severely affected animals, the kidney consists of a fluid-filled sac containing clear serous fluid. On microscopic examination, there is marked dilation of the renal pelvis, with excavation of the renal medulla, reduction in the length of the collecting tubules, and absence of an inflammatory response. Differential diagnoses include pyelonephritis, polycystic kidneys, and renal papillary necrosis. In most strains, unilateral or bilateral hydronephrosis is often an incidental finding at necropsy. The defect may be fatal when bilateral. There may be an increased susceptibility to superimposed renal infections due to urine stasis.
More on the topic Hydronephrosis:
- Hydronephrosis
- Hydronephrosis
- URINARY TRACT MALFORMATIONS
- Renal Papillary Hyperplasia
- ABDOMINAL MASS/LUMP
- Murine Urologic Syndrome (MUS)
- BIBLIOGRAPHY FOR AGE-, MISCELLANEOUS-, ENVIRONMENTAL- AND DRUG-RELATED DISORDERS
- Amyloidosis and Amyloid-Like Nasal Deposition
- 22 Hepatic lipidosis in a cat
- Index