Congenital portosystemic shunts in dogs

N. Kashliak; V. Vlizlo

doi:10.15421/0225142

N. Kashliak Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv
V. Vlizlo Stepan Gzhytskyi National University of Veterinary Medicine and Biotechnologies Lviv

Keywords: dogs, portosystemic shunt, ammonia, liver lesion, computed tomography.

Abstract

Congenital portosystemic shunt is one of the commonest congenital abnormalities in dogs. The objective of our study was to determine the presence of portosystemic shunts in the dogs using computed tomography, point out the typical symptoms and changes in the blood parameters that occur during this pathology. We analyzed nine patients with portosystemic shunts and nine clinically healthy dogs. Each group contained four Yorkshire Terriers, two Miniature Poodles, two Maltese dogs, and one mixed-breed dog. The animals were clinically examined, underwent computed tomography, and their blood was analyzed. Computed tomography revealed congenital portosystemic shunts in the dogs of small breeds aged six months to four years. Of the seven patients that underwent computed tomography, five were diagnosed extrahepatic portosystemic shunts (two M i niature Poodles, one mixed-breed dog, one Maltese dog, and one Yorkshire Terrier) and two were found to have intrahepatic portosystemic shunt (Yorkshire Terrier and Maltese dog). According to the results of computed tomography, we determined that the connection of the shunting vessel occurred through the gastric, splenic, azygos, and phrenic veins with the caudal vena cava. In the plasma of the patients with portosystemic shunts, the ammonia concentration was five times higher. Hyperamm o nemia was closely associated with the complexity of the portosystemic shunt and the severity of pathological process. The ill dogs were observed to have typical symptoms of damaged central nervous system – apathy, stupor, sopor, muscle tremor, hyperkinesias, and static and dynamic ataxia. The nervous symptoms and increase in the ammonia content in blood are the symptoms that warrant computed tomography to verify the diagnosis of portosystemic shunts. The patients had impaired fun c tions and the structure of the liver, especially notable in the parameters in blood serum, such as increased contents of total bile acids and bilirubin, reduced albumin content, and high activities of ALT, AST, and AP. Blood of a part of the ill dogs co n tained reduced contents of hemoglobin, number of erythrocytes, and hematocrit, increased contents of leukocytes and young forms of neutrophils, and also reduced number of platelets. In the future, we are going to analyze the efficacy of surgical trea t ment of dogs with portosystemic shunts.

References

Balda, I. O., Selmic, L. E., Stamenova, P., Simpson, M., Lipscomb, V. J., Kummeling, A., Devriendt, N., de Rooster, H., Grzywa, K. M., Tivers, M. S., Chanoit, G., Maggiar, A., Billet, J. P., Soto Muñoz, R., Oramas, A., Singh, A., & Mullins, R. A. (2025). Prognostic factors for short-term survival of cats that experienced postattenuation neurologic signs after surgical attenuation of single congenital portosystemic shunts. Veterinary Surgery, 54(5), 930–944.

Bedford, S. (2017). Portosystemic shunts in canines – an overview. Veterinary Nursing Journal, 32(9), 249–253.

Bellafante, D., Gioia, S., Faccioli, J., Riggio, O., Ridola, L., & Nardelli, S. (2024). The management of hepatic encephalopathy from ward to domiciliary care: Current evidence and gray areas. Journal of Clinical Medicine, 13(1), 166.

Berent, A., & Tobias, K. M. (2018). Hepatic vascular anomalies. In: Johnston, S. A., & Tobias, K. M. (Eds.). Veterinary surgery: Small animal expert consult. 2nd ed. Saunders, Elsevier. Pp. 1852–1886.

Butterworth, R. F. (2019). Hepatic encephalopathy in cirrhosis: Pathology and pathophysiology. Drugs, 79(1), 17–21.

Caporali, E. H. G., Phillips, H., Underwood, L., & Selmic, L. E. (2015). Risk factors for urolithiasis in dogs with congenital extrahepatic portosystemic shunts: 95 cases (1999–2013). Journal of the American Veterinary Medical Association, 246, 530–536.

Cullen, J. M., van den Ingh, T., Grinwis, G. C., & Fieten, H. (2021). Morphological classification of circulatory disorders of the canine and feline liver. In: WSAVA Liver Standardization Group, Rothuizen, J., Bunch, S. E., Charles, J. A., Cullen, J. M., Desmet, V. J., Szatmári, V., Twedt, D. C., van den Ingh, T. S. G. A. M., van Winkle, T., & Washabau, R. J. (Eds.). WSAVA standards for clinical and histological diagnosis of canine and feline liver disease. Rothuizen, Saunders, Elsevier. Pp. 41–59.

European Association for the Study of the Liver (2022). EASL clinical practice guidelines on the management of hepatic encephalopathy. Journal of Hepatology, 77, 807–824.

Farhoodimoghadam, M., Reagan, K. L., & Zwingenberger, A. L. (2024). Diagnosis and classification of portosystemic shunts: A machine learning retrospective case-control study. Frontiers in Veterinary Science, 11, 1291318.

Fukushima, K., Kanemoto, H., Ohno, K., Takahashi, M., Fujiwara, R., Nishimura, R., & Tsujimoto, H. (2014). Computed tomographic morphology and clinical features of extrahepatic portosystemic shunts in 172 dogs in Japan. The Veterinary Journal, 199(3), 376–381.

Gow, A. G. (2017). Hepatic encephalopathy. Veterinary Clinics of North America: Small Animal Practice, 2017, 47(3), 585–599.

Ishigaki, M., Or, K., de Rooster, H., Kutara, K., & Asano, K. (2016). Determination of porto-azygos shunt anatomy in dogs by computed tomography angiography. Veterinary Surgery, 45, 1005–1012.

Jaffe, A., Lim, J. K., & Jakab, S. S. (2020). Pathophysiology of hepatic encephalopathy. Clinical Liver Disease, 24(2), 175−188.

Kabaria, S., Dalal, I., Gupta, K., Bhurwal, A., Minacapelli, C. D., Catalano, C., & Rustgi, V. (2021). Hepatic encephalopathy: A review. European Medical Journal Hepatology, 9(1), 89–97.

Kashliak, N. O., & Vlizlo, V. V. (2023). Symptoms, biochemical indicators and general blood analysis for hepatopathy in dogs. Scientific Messenger of Lviv National University of Veterinary Medicine and Biotechnologies, Series: Veterinary Sciences, 25(112), 193–200.

Kashliak, N., & Vlizlo, V. (2024). Hepatic encephalopathy in dogs. Regulatory Mechanisms in Biosystems, 15(4), 921–925.

Kawaguchi, T., Suzuki, F., Imamura, M., Murashima, N., Yanase, M., Mine, T., Fujisawa, M., Sato, I., Yoshiji, H., & Okita, K. (2019). Rifaximin-altered gut microbiota components associated with liver/neuropsychological functions in patients with hepatic encephalopathy: An exploratory data analysis of phase II/III clinical trials. Hepatology Research, 49, 404–418.

Kim, S. E., Giglio, R. F., Reese, D. J., Reese, S. L., Bacon, N. J. & Ellison, G. W. (2013). Сomparison of computed tomographic angiography and ultrasonography for the detection and characterization of portosystemic shunts in dogs. Veterinary Radiology and Ultrasound, 54, 569–574.

Konstantinidis, A. O., Adamama-Moraitou, K. K., Patsikas, M. N., & Papazoglou, L. G. (2023a). Congenital portosystemic shunts in dogs and cats: Treatment, complications and prognosis. Veterinary Sciences, 10(5), 346.

Konstantinidis, A. O., Patsikas, M. N., Papazoglou, L. G., & Adamama-Moraitou, K. K. (2023b). Congenital portosystemic shunts in dogs and cats: Classification, pathophysiology, clinical presentation and diagnosis. Veterinary Sciences, 10(2), 160.

Kozak, M., Petruh, I., Kovalchuk, I., & Vlizlo, V. (2025). Toxicity analysis of amoxicillin, polyphosphate ester and its complex with amoxicillin on mice. Scientific Reports, 15, 18150.

Kraun, M. B., Nelson, L. L., Hauptman, J. G., & Nelson, N. C. (2014). Analysis of the relationship of extrahepatic portosystemic shunt morphology with clinical variables in dogs: 53 cases (2009–2012). Journal of the American Veterinary Medical Association, 245(5), 540–549.

Krishnarao, A., & Gordon, F. D. (2020). Prognosis of hepatic encephalopathy. Clinical Liver Disease, 24, 219–229.

Kurihara, H., Moore, G., & Murakami, M. (2024). Computed tomographic hepatic volumetry in dogs with congenital portosystemic shunts. Veterinary Sciences, 11(9), 569–574.

Lawrence, Y. A., & Steiner, J. M. (2017). Laboratory evaluation of the liver. Veterinary Clinics of North America: Small Animal Practice, 47, 539–553.

Lester, C., Cooper, J., & Peters, R. M. (2016). Retrospective evaluation of acute liver failure in dogs (1995–2012): 49 cases. Journal of Veterinary Emergency and Critical Care, 26(4), 559–567.

Lidbury, J. (2025). Complications of liver disease. Veterinary Clinics of North America: Small Animal Practice, 55(4), 559–577.

Lidbury, J. A., Ivanek, R., Suchodolski, J. S., & Steiner, J. M. (2015). Putative precipitating factors for hepatic encephalopathy in dogs: 118 cases (1991–2014). Journal of the American Veterinary Medical Association, 247(2), 176–183.

Lima, L. C. D., Miranda, A. S., Ferreira, R. N., Rachid, M. A., & Simões e Silva, A. C. (2019). Hepatic encephalopathy: Lessons from preclinical studies. World Journal of Hepatology, 11(2), 173–185.

MacEwan, I., & Thompson, D. (2023). Intramural esophageal location of a portosystemic shunt in a dog with two congenital portosystemic shunts on CT angiography. Veterinary Radiology and Ultrasound, 64, 45–49.

Mankin, K. M. (2015). Current concepts in congenital portosystemic shunts. Veterinary Clinics of North America: Small Animal Practice, 45(3), 477–487.

Moon, S. J., Kim, J. W., Kang, B. T., Lim, C. Y., & Park, H. M. (2012). Magnetic resonance imaging findings of hepatic encephalopathy in a dog with a portosystemic shunt. Journal of Veterinary Medical Science, 74(3), 361–366.

Moritz, A. (2014). Klinische Labordiagnostik in der Tiermedizin. In: Moritz, A. (Ed.). Schattauer, Stuttgart.

Mullins, R. A., Escribano Carrera, A., Anderson, D. M., Billet, J., Brissot, H., Broome, C., de Rooster, H., Kirby, B. M., Pratschke, K. M., Tivers, M. S., White, R. N., Yool, D. A., & Youmans, K. R. (2021). Postattenuation neurologic signs after surgical attenuation of congenital portosystemic shunts in dogs: A review. Veterinary Surgery, 51(1), 23–33.

Nardelli, S., Bellafante, D., Ridola, L., Faccioli, J., Riggio, O., & Gioia, S. (2023). Prevention of post-tips hepatic encephalopathy: The search of the ideal candidate. Metabolic Brain Disease, 38, 1729–1736.

Nelson, N. C. (2011). Anatomy of extrahepatic portosystemic shunts in dogs as determined by computed tomography angiography. Veterinary Radiology and Ultrasound, 52(5), 498–506.

Parry, A. T., & White, R. N. (2017). Comparison of computed tomographic angiography and intraoperative mesenteric portovenography for extrahepatic portosystemic shunts. Journal of Small Animal Practice, 58(1), 49–55.

Phillips, R. K., Blake, A. B., Tivers, M. S., Chan, A., Ishii, P. E., Suchodolski, J. S., Steiner, J. M., & Lidbury, J. A. (2025). Serum amino acid profiles in dogs with a congenital portosystemic shunt. Metabolites, 15(4), 258.

Pietersma, J. (2018). Spongiform encephalomyelopathy in a calf with a congenital portosystemic shunt. The Canadian Veterinary Journal, 59(9), 1005–1007.

Poggi, E., Rubio, D. G., Pérez Duarte, F. J., del Sol, J. G., Borghetti, L., Izzo, F., & Cinti, F. (2022). Laparoscopic portosystemic shunt attenuation in 20 dogs (2018–2021). Veterinary Surgery, 51, 138–149.

Rose, C. F., Amodio, P., Bajaj, J. S., Dhiman, R. K., Montagnese, S., Taylor-Robinson, S. D., Vilstrup, H., & Jalan, R. (2020). Hepatic encephalopathy: Novel insights into classification, pathophysiology and therapy. Journal of Hepatology: Home Page, 73, 1526–1547.

Seller, S., Weisse, C., & Fischetti, A. J. (2022). Intrahepatic venous collaterals in dogs with congenital intrahepatic portosystemic shunts are associated with focal shunt or hepatic vein narrowing. Veterinary Radiology and Ultrasound, 63, 64–72.

Simonov, M., & Vlizlo, V. (2015). Some blood markers of the functional state of liver in dairy cows with clinical ketosis. Bulgarian Journal of Veterinary Medicine, 18(1), 74–82.

Spillane, A. M., Haraschak, J. L., & McMichael, M. A. (2021). Resolution of severe neurologic signs following intravenous lipid emulsion therapy in a young dog with a portosystemic shunt: Case report. Frontiers in Veterinary Science, 8, 798198.

Sugimoto, S., Maeda, S., Tsuboi, M., Saeki, K., Chambers, J. K., Yonezawa, T., Fukushima, K., Fujiwara, R., Uchida, K., Tsujimoto, H., Matsuki, N., & Ohno, K. (2018). Multiple acquired portosystemic shunts secondary to primary hypoplasia of the portal vein in a cat. Journal of Veterinary Medical Science, 80(6), 874–877.

Takeuchi, R., Ishigaki, K., Iida, K., Ishikawa, C., Shiozawa, N., Yamaoka, S., Yamada, N., Sakamoto, Y., Sakai, M., & Asano, K. (2025). Use of computed tomography angiography has potential in planning surgical treatment of an extrahepatic portosystemic shunt in dogs. American Journal of Veterinary Research, 86(4), 333.

Tivers, M. S., Handel, I., Gow, A. G., Lipscomb, V. J., Jalan, R., & Mellanby, R. J. (2014). Hyperammonemia and systemic inflammatory response syndrome predicts presence of hepatic encephalopathy in dogs with congenital portosystemic shunts. PLoS One, 9(1), e82303.

Umek, N., Plut, D., Žel, M., & Petrič, D. A. (2023). Radiologic evaluation of portosystemic shunts in humans and small animals: Review of the literature with clinical case reports. Diagnostics, 13(3), 482.

Vallarino, N., Pil, S., Devriendt, N., Or, M., Vandermeulen, E., Serrano, G., Paepe, D., Bosmans, T., & de Rooster, H. (2020). Diagnostic value of blood variables following attenuation of congenital extrahepatic portosystemic shunt in dogs. Veterinary Record, 187(7), e48.

Van den Bossche, L., & van Steenbeek F. G. (2020). Canine congenital portosystemic shunts: Disconnections dissected. The Veterinary Journal, 211, 14–20.

Vlizlo, V., Prystupa, O., Slivinska, L., Gutyj, B., Maksymovych, I., Shcherbatyy, A., Lychuk, M., Partyka, U., Chernushkin, B., Rusyn, V., Leno, M., & Leskiv, K. (2023). Treatment of animals with fatty liver disease using a drug based on the seeds of Silybum marianum. Regulatory Mechanisms in Biosystems, 14(3), 424–431.

White, R. N., & Parry, A. T. (2015). Morphology of congenital portosystemic shunts involving the right gastric vein in dogs. Journal of Small Animal Practice, 56, 430–440.

White, R., Parry, A., & Shales, C. (2018). Implications of shunt morphology for the surgical management of extrahepatic portosystemic shunts. Australian Veterinary Journal, 96, 433–441.

Willems, D. S., Kranenburg, L. C., Ensink, J. M., Kummeling, A., Wijnberg, I. D., & Veraa, S. (2019). Computed tomography angiography of a congenital extrahepatic splenocaval shunt in a foal. Acta Veterinaria Scandinavica, 61(1), 39.

Williams, A., Gow, A., Kilpatrick, S., Tivers, M., Lipscomb, V., Smith, K., Day, M. O., Jeffery, N., & Mellanby, R. J. (2020). Astrocyte lesions in cerebral cortex and cerebellum of dogs with congenital ortosystemic shunting. Journal of Veterinary Science, 21(3), e44.

Winkler, J. T., Bohling, M. W., Tillson, D. M., Wright, J. C., & Ballagas, A. J. (2003). Portosystemic shunts: Diagnosis, prognosis, and treatment of 64 cases (1993–2001). Journal of the American Animal Hospital Association, 39, 169–185.

Zelenina, O., Vlizlo, V., Kozak, M., Ostapiv, D., Samaryk, V., Dron, I., Stetsko, T., Skrypka, M., Tomchuk, V., Danchuk, O., & Levchenko, A. (2022). Antimicrobial activity of the PEGylated antibiotic enrofloxacin and its functional and structural effect on the liver in rats. Journal of Applied Pharmaceutical Science, 12(6), 68–75.