PORTO SYSTEMIC SHUNTS
CAN CAUSE SEIZURES IN DOGS
Systemic Shunts (also known as Portacaval Shunts) are abnormal communications between the
portal vein coming from the gastrointestinal tract and the posterior vena cava, which
carries blood back to the heart. The
communications are normally present during fetal life and then close off shortly after
birth. When the communications fail to close
properly, the vessels serve as shunts so that portal blood flow does not pass through the
liver for detoxification before being delivered to the rest of the body.
Porto Systemic shunts are congenital, that is, present at birth. In some cases, an acquired Porto Systemic shunt
can develop secondary to an underlying liver disease.
Congenital Porto Systemic shunts are most common in Miniature Schnauzers, Yorkshire
Terriers, Irish Wolfhounds, Cairn Terriers, and Old English Sheepdog, but any breed can be
include depression, seizures, ataxia (loss of muscle control), vomiting, excessive thirst
and retarded growth. Signs and symptoms are
usually present by 6 months of age, but congenital Porto-Systemic shunts are occasionally
not recognized until middle age. Diagnosis is
based on blood tests and x-ray imaging study. Medication
is often helpful, but definitive treatment is surgery to close off the shunt.