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Abstract

Amongst the potential neurotoxins implicated in the pathogenesis of hepatic encephalopathy, manganese emerges as a new candidate. In patients with chronic liver diseases, manganese accumulates in blood and brain leading to pallidal signal hyperintensity on T1-weighted Magnetic Resonance (MR) Imaging. Direct measurements in globus pallidus obtained at autopsy from cirrhotic patients who died in hepatic coma reveal 2 to 7-fold increases of manganese concentration. The intensity of pallidal MR images correlates with blood manganese and with the presence of extrapyramidal symptoms occurring in a majority of cirrhotic patients. Liver transplantation results in normalization of pallidal MR signals and disappearance of extrapyramidal symptoms whereas transjugular intrahepatic portosystemic shunting induces an increase in pallidal hyperintensity with a concomitant deterioration of neurological dysfunction. These findings suggest that the toxic effects of manganese contribute to extrapyramidal symptoms in patients with chronic liver disease. The mechanisms of manganese neurotoxicity are still speculative, but there is evidence to suggest that manganese deposition in the pallidum may lead to dopaminergic dysfunction. Future studies should be aimed at evaluating the effects of manganese chelation and/or of treatment of the dopaminergic deficit on neurological symptomatology in these patients.

Public Health Strategies for Western Bangladesh That Address Arsenic, Manganese, Uranium, and Other Toxic Elements in Drinking Water

“…Mn is required for human nutrition; however, the accumulation of Mn may cause hepatic encephalopathy in humans (Layrargues et al 1998). The chronic ingestion of Mn in drinking water is associated with neurologic damage in humans (Kondakis et al 1989; WHO 1996a, 1996b).…”

Management of Hepatic Encephalopathy

“…Zinc supplementation (600 mg/day) has been studied without obvious benefit though replacement should be considered if the patient is deficient [11]. Autopsy specimens from patients with hepatic coma and pallidal MR images of patients with HE suggest that manganese deposition in the basal ganglia may be a factor [12, 13]. However, as with earlier studies evaluating the role of gut bacterial products like mercaptans, phenols and medium- and short-chain fatty acids [14], there has been little cumulative evidence to support targeted treatment strategies.…”

Identification and quantification of heavy metals in local drinks in Northern Zone of Nigeria

“…The patient suffered nausea, vomiting, fever and severe anemia (Galley et al, 1972). Lead is toxic to Bakare-Odunola and Mustapha 127 such as the nervous, gastrointestinal and genital system (Abou-Arab, 2001) and also a possible human carcinogen (Yakasai et al, 2004) and the accumulation of Mn may cause hepatic encephalopathy (Layrangues et al, 1998). Outbreak of "Minamata" disease caused by Mercury poisoning has been reported in Iraq and Canada.…”