Portosystemic shunts are abnormal blood vessel connections that bypass the liver in dogs, causing neurological and growth problems from birth that require surgical correction for long-term welfare.
Portosystemic shunts cause significant suffering from early life. Puppies with PSS often appear dull, small and neurologically abnormal from the first weeks of life — the hepatic encephalopathy episodes, triggered by feeding, cause confusion, apparent blindness and seizure-like activity that is frightening to observe. The unpredictability of episodes — which can range from mild post-prandial spaciness to severe seizures and collapse — creates a state of chronic uncertainty that itself represents significant welfare impact. Growth failure means affected puppies are smaller than littermates, affecting social hierarchies and physical development. Medical management requires strict dietary protein restriction, which affects palatability and nutritional adequacy. Surgical correction, while requiring general anaesthesia and post-operative care, typically produces dramatic improvements: dogs that were neurologically impaired before surgery often show remarkable functional recovery within weeks. The risk of post-operative portal hypertension (from sudden flow redirection) is a manageable complication with appropriate surgical technique.