Portosystemic shunts are abnormal blood vessel connections that bypass the liver, causing toxin accumulation in the brain and liver failure in affected dogs, with surgical correction offering the best outcomes.
Dogs with portosystemic shunts suffer the neurological consequences of ammonia toxicity. Hepatic encephalopathy causes confusion, disorientation, seizures, and coma - profoundly distressing experiences for affected dogs. Many young dogs with congenital shunts show stunted development and episodic neurological crises from the first months of life. The post-meal worsening as protein is absorbed and ammonia rises can cause dramatic neurological deterioration within hours of eating. Without treatment, dogs experience recurring neurological crises throughout their lives. Surgical correction, when successful, can eliminate these episodes completely - the welfare transformation is dramatic. Congenital shunts in predisposed breeds can be reduced through genetic selection by breeders.