Generalized motor seizures after portosystemic shunt ligation in dogs: five cases (1981-1988).

Severe generalized motor seizures developed in 5 dogs between 13 hours and 3 days after surgical attenuation of a single extrahepatic portosystemic shunt. Three dogs died, and a fourth was euthanatized because of poor prognosis for recovery. The fifth dog, although improved, was still not clinically normal 15 months after surgery. An intra-or extracranial cause for the seizures could not be identified in any of these dogs. Postmortem examination results in 3 dogs were similar to findings previously reported in dogs with portosystemic shunts, but which did not undergo surgical shunt ligation. Of the 5 dogs, 4 were greater than 18 months old, which may indicate that older dogs are more likely to develop seizures after shunt ligation than are younger dogs.