Unilateral pyelonephritis with encapsulated structure in a dog

Area of Science:

• Veterinary Pathology
• Canine Infectious Diseases
• Renal Pathology

Background:

• Portosystemic shunts in dogs can lead to complex metabolic disturbances.
• Renal complications, including pyelonephritis, can occur but are not always well-characterized.
• Severe clinical signs like ascites and hyperammonemia were observed.

Purpose of the Study:

• To investigate the cause of renal papillary necrosis in a dog with a portosystemic shunt.
• To identify the etiological agent responsible for the observed pathology.
• To document a rare manifestation of canine pyelonephritis.

Main Methods:

• Necropsy and histological examination of renal tissue.
• Mass spectrometry analysis to identify proteins within the encapsulated structure.
• Polymerase Chain Reaction (PCR) and immunohistochemistry for pathogen confirmation.

Main Results:

• Renal papillary necrosis was identified in the right renal pelvis.
• An encapsulated structure containing basophilic granules was found within the renal pelvis.
• Mass spectrometry, PCR, and immunohistochemistry confirmed Staphylococcus pseudintermedius infection.

Conclusions:

• This is the first reported case of canine renal papillary necrosis with an encapsulated structure.
• The findings indicate a severe manifestation of pyelonephritis caused by Staphylococcus spp.
• The study highlights the importance of identifying specific bacterial pathogens in complex renal diseases.