Reversible Subacute Parkinsonism and Cognitive Decline in a Patient With Acquired Hepatocerebral Degeneration: A Case Report.

Acquired hepatocerebral degeneration (AHD) is a rare neurological disorder associated with chronic liver disease and portosystemic shunting. It is characterized by parkinsonism, cognitive impairment, and bilateral hyperintensities in the globus pallidus on T1-weighted imaging. Although traditionally considered irreversible, recent reports suggest that AHD may be partially reversible with early intervention. We describe the case of a 71-year-old Japanese man with a history of chronic alcohol use and liver dysfunction who developed subacute parkinsonism and cognitive decline, initially preceded by depressive symptoms. He was treated for major depressive disorder before neurological signs emerged. Laboratory testing revealed macrocytic anemia, mild hepatic dysfunction, and hyperammonemia. T1-weighted imaging showed bilateral hyperintensities in the globus pallidus, despite a normal serum manganese level. A diagnosis of AHD was made based on these findings. Conservative treatment with IV branched-chain amino acids and oral lactulose led to rapid and marked clinical improvement. This case highlights the potential reversibility of early-stage AHD and emphasizes the importance of recognizing psychiatric symptoms, such as depression, as possible early manifestations. Recent literature has documented similar cases of AHD initially misdiagnosed as primary psychiatric disorders, underscoring the need for careful diagnostic evaluation when basal ganglia abnormalities are detected on MRI. Early recognition and metabolic correction may help prevent irreversible neurological damage and improve patient outcomes.