Transurethral retrograde ureteral catheterisation and renal lavage in a dog with severe pyonephrosis and concurrent leishmaniasis

A 5‐year‐old dog presented with severe left pyonephrosis and ureteral obstruction with marked proteinuria, serologically confirmed Leishmania infection, and suspected diskospondylitis. Dense purulent intraluminal material raised concern for occlusion or persistent infection, with conventional ureteral stenting or subcutaneous ureteral bypass. After failed antegrade guidewire passage, transurethral retrograde ureteral catheterisation (TRUC) was performed via cystotomy using a 6‐Fr polyurethane urinary catheter advanced into the renal pelvis. The catheter provided temporary decompression, drainage and repeated renal pelvic lavage. Renal pelvic dilation decreased markedly, and serum creatinine fell from a peak of 3.1 to 1.8 mg/dL during hospitalisation. The catheter was removed before discharge. At 2.5‐month telephone follow‐up, minor‐to‐moderate clinical improvement was reported, but objective laboratory reassessment was unavailable. TRUC may represent a salvage option when conventional interventional approaches are considered unsuitable or unavailable.