Portal-systemic encephalopathy in non-cirrhotic patients: classification of clinical types, diagnosis and treatment.
Hepatic encephalopathy is suspected in non-cirrhotic cases of encephalopathy because the symptoms are accompanied by hyperammonaemia. However, the cause of the large portal-systemic shunt formation observed in these cases is not clear, as cirrhosis and portal hypertension are absent. The frequency of such cases reported in the literature is increasing with progress and spread of abdominal imaging diagnostic techniques. Some cases have been misdiagnosed as psychiatric diseases (dementia, depression and others) and consequently patients have been hospitalized in psychiatric institutions or geriatric facilities. Some paediatric cases have also been misdiagnosed. Therefore, the importance of accurate diagnosis of this disease should be strongly emphasized. Some paediatric cases have also been misdiagnosed. When psychoneurological symptoms are suggestive of hepatic encephalopathy but objective and subjective symptoms or abnormal values of liver function tests are not sufficiently indicative of liver cirrhosis, portal-systemic encephalopathy should be suspected. Abnormal angiograms of the portal vein, superior mesenteric vein or splenic vein are conclusive evidence of portal-systemic encephalopathy. Transrectal portal scintigraphy also provides information useful for detection of shunts and a quantitative estimation of shunt index. We classified the disease into five types based on whether the shunt is formed inside or outside the liver. Type I (intrahepatic type) designates cases in which shunts are located between the portal and systemic veins. Type II designates a type of intra/extrahepatic shunt that originates from the umbilical part of the portal vein and serpentines in the liver, then leaves the liver. Type III (extrahepatic type) occurs most frequently. Type IV (extrahepatic) is accompanied by shunts similar to those in type III, but hepatic pathology presents as idiopathic portal hypertension. Type V (extrahepatic) represents the congenital absence of the portal vein, where the superior mesenteric vein joins the intrahepatic inferior vena cava or the left renal vein. The prevalence of each type in our country was examined by a nationwide investigation. In addition to the conventional diet or drug treatments, obliteration by less invasive interventional radiology using a metallic coil and ethanol has recently been used more frequently than surgical occlusion of shunts. Shunt-preserving disconnection of portal and systemic circulation and partial splenic artery embolization are also performed. International investigation of the disease status and establishment of diagnostic and therapeutic methods for the disease are awaited and investigation of long-term prognosis after therapy is also necessary.
Watanabe
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Third Department of Internal Medicine, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Toyama-ken, Japan. awat@toyama-mpu.ac.jp
D003937:Diagnosis, Differential; D004374:Ductus Arteriosus, Patent / Q000473:pathology; D006501:Hepatic Encephalopathy / Q000145:classification / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D016031:Liver Transplantation; D011169:Portal Vein / Q000002:abnormalities; D011170:Portasystemic Shunt, Surgical; D015995:Prevalence; D011379:Prognosis; D013683:Telangiectasia, Hereditary Hemorrhagic / Q000473:pathology