Ureteral obstructions in dogs and cats: a review of traditional and new interventional diagnostic and therapeutic options

Objective – To describe and review both traditional and newer diagnostic and therapeutic options for canine and feline ureteral obstructions currently being performed clinically in veterinary medicine. Data Sources – A Medline search with no date restrictions was used for this review. Human Data Synthesis – The human literature would support the use of minimally invasive endourological techniques for the treatment of nearly all causes of ureteral obstructions, whenever possible. This typically includes extracorporeal shockwave lithotripsy, intracorporeal lithotripsy via retrograde ureteroscopy or antegrade percutaneous nephroureterolithotomy, ureteral stenting, percutaneous nephrostomy tube placement, and laparoscopic endopyelotomy. Typically open surgery is only suggested in cases of ureteral or gynecological malignancy when en bloc resection is considered a good option, or when various methods of endourological techniques have failed. Veterinary Data Synthesis – The veterinary literature is scarce on the use of interventional endourological techniques for the treatment of ureteral obstructions and has been growing over the last 5 years. The current literature reports the use of extracorporeal shockwave lithotripsy for ureteral stones, as well as the use of ureteral stents for the treatment of trigonal obstructive transitional cell carcinoma, ureterolithiasis, and ureteral strictures. Traditional surgical interventions, like ureterotomy, ureteronephrectomy, and ureteral reimplantation is more vastly reported and accepted. This review will focus on new clinical data using interventional endourological techniques for ureteral obstructions. Conclusions – Various treatment options for ureteral obstructions are now available for veterinary patients, and the trend away from traditional surgical techniques will hopefully be followed now that they are technically and clinically available for dogs and cats.     

Radiographic features of suspected suture‐associated cystic calculi in dogs

This retrospective case series describes the radiographic features of suspected suture‐associated cystic calculi in six dogs with a history of at least one or multiple prior cystotomies. One of the dogs presented twice. Suspected suture‐associated cystic calculi were multifocal, short, predominantly linear mineral opacities localized in the center of the urinary bladder on abdominal radiographs. One patient (n = 1) presented with multifocal round, pin point, and linear radiopaque calculi. The calculi were all calcium oxalate in composition. On gross examination, the calculi had a hollow center. Six cystotomies used monofilament absorbable suture material (polydioxanone [n = 4] or poliglecaprone 25 [n = 1]) in prior cystotomies. Suture material in two of the cases was unknown. Suspected suture‐associated cystic calculi are a rare occurrence in veterinary medicine but should be considered in dogs that have a history of prior cystotomy, hollow core on gross analysis, and radiographic evidence of mineral opaque, predominantly linear, cystic calculi.     

Light and electron microscopic features of eperythrozoon-like parasites in a North American opossum (Didelphis virginiana).

Epierythrocytic parasites associated with a severe anemic episode have not been previously reported in the opossum. A Wright-Giemsa-stained peripheral blood smear from an anemic North American opossum (Didelphis virginiana) revealed numerous organisms attached to red blood cells either singularly or in chains. Ring forms of the organism were common and could be found free in the plasma. Electron microscopy revealed that these organisms were attached to the intact plasma membrane in depressions on the surface of red blood cells. Delicate fibrils between the organism and adjacent membrane were observed. The organisms were round to oval with a diameter of 300-750 nm and were enclosed by a single limiting membrane. The light and electron microscopic features of these epierythrocytic organisms are similar to those reported for Eperythrozoon and Haemobartonella species.     

α-Luminol prevents decreases in glutamate, glutathione, and glutamine synthetase in the retinas of glaucomatous DBA/2J mice

Objective  To test the hypothesis that in DBA/2J mice, oxidative stress decreases glutamine synthetase (GS) levels resulting in a loss of neuronal glutamate and that the antioxidant α-luminol (GVT®) decreases this stress and glutamate loss in some types of glaucoma.
Animals  DBA/2J mice were separated into two groups, of which one was not treated, and the other treated with GVT in the drinking water. At 7 months of age, retinas were examined from five untreated DBA/2J mice, seven GVT-treated mice, and five C57BL/6 mice (negative controls).
Methods  Serial 0.5 μm plastic sections were immunogold stained for glutamate, GS, and total glutathione, followed by image analysis for staining patterns and density.
Results  Focal decreases in glutamate immunostaining were common in the inner nuclear layer (INL) of DBA/2J retinas, but not in C57BL/6 or GVT-treated DBA/2J retinas. Decreases in glutathione and GS immunostaining were found in DBA/2J retinal regions where neuronal glutamate immunostaining was reduced. Retinas from GVT-treated DBA/2J had no significant decreases in INL levels of glutamate, glutathione, or GS.
Conclusions  Retinas of dogs with primary glaucoma are reported to have focal depletion of neuronal glutamate. In DBA/2J mice, similar changes occur prior to the development of clinical disease. In these focal glutamate-depleted regions, levels of glutathione and GS are also reduced, consistent with the hypothesis that oxidative stress contributes to retinal changes in glaucoma. The ability of GVT, an antioxidant, to inhibit retinal abnormalities in DBA/2J mice provides further support for this hypothesis.