Portosystemic shunts are congenital vascular abnormalities that cause toxins to bypass the liver, producing neurological signs and growth failure in young dogs that can be corrected surgically.
Young dogs with PSS often show neurological signs from early life — their failure to thrive and recurring disorientation or seizures represents significant welfare impairment during the most important developmental period. HE episodes cause acute distress and carry the risk of status epilepticus. Surgical correction, when performed early and successfully, is transformative — most dogs return to normal neurological function and grow appropriately. The welfare argument for early surgical referral is strong: medical management controls symptoms but does not address the underlying abnormality, meaning dogs remain at risk of HE episodes throughout their lives. Genetic testing and breed health screening for PSS in predisposed breeds would allow welfare-positive breeding decisions.