Acquired hepatocerebral degeneration.

Repeated episodes of liver failure or chronic liver cirrhosis may cause acquired (non-Wilsonian) hepatocerebral degeneration (AHCD). Patients with AHCD may show cognitive deficits, ataxia, dysarthria, movement disorders, including parkinsonism, and sometimes myelopathy. Various parenchymal and cholestatic hepatic disorders may result in AHCD. Most patients with AHCD have evidence of portosystemic shunting without necessarily having abnormal liver function. Recent evidence suggests manganese plays a crucial role in the pathogenesis of AHCD. Excess dietary manganese is rapidly cleared by the liver before reaching the systemic circulation. In patients with cirrhosis and portosystemic shunting, manganese bypasses the liver and accumulates in the internal pallidum, while serum manganese levels may be normal or increased. Magnetic resonance imaging abnormalities mainly consist of a signal hyperintensity on T1-weighted images in the internal pallidum. It may also be seen in the putamen, the caudate nucleus, the capsula interna, the mesencephalon, and the cerebellum, and is believed to reflect local manganese accumulation. No specific treatment of AHCD exists. Controlled studies are lacking, but case reports have stressed the usefulness of branched-chain amino acid therapy, trientine, and liver transplantation for the treatment of movement disorders. Levodopa may be efficacious in the treatment of AHCD parkinsonism.