Disorder - Portosystemic shuntOrgan Systems Involved
Intrahepatic shunt; Extrahepatic shunt; Patent ductus venosus; Congenital portocaval shunt; Hepatic microdysplasia
Portosystemic shunts are caused by an abnormal vessel that diverts blood from the liver into a vein going elsewhere in the body. This allows toxins from the liver to reach other organs. Symptoms are either due to the effect of liver toxins on the brain (hepatic encephalopathy), or from the presence of stones in the urinary tract. Symptoms include excessive salivation, altered consciousness, seizures, wobbliness, tremors and bumping into things. Other signs include not eating or poor appetite, vomiting, diarrhoea, drinking and urinating a lot and delayed recovery from anaesthetics. The presence of stones (urate calculi) in the urinary tract can cause blood in the urine and difficulty urinating. Affected cats are often smaller than their littermates and others cats their age.
Cats at Risk
As the majority of portosystemic shunts are congenital it is generally seen in immature cats – the majority of affected cats show signs by six months of age. Males are affected more commonly than females. Concurrent diseases reported in cats affected by shunts include heart murmurs, undescended testicles in males and abdominal hernias.
Treatment is achieved by surgery to tie off the vessel creating the problem. Medical management can be used to reduce the production and absorption of ammonia and other toxins and reduce the clinical signs. Low-protein, high-carbohydrate diets should be fed and in severe cases the use of intravenous fluid therapy and anti-seizure medication is needed.