Factors associated to hypermanganesemia in patients receiving home parenteral nutrition

Background: Home parenteral nutrition (HPN) patients often present hypermanganesamia.Aim: To examine which factors may be associated to hypermanganesemia in HPN patients. Methods: Plasma manganese (Mn), liver function tests, C-reactive protein concentrations, erythrocyte sedimentation rate (ESR), tumor necrosis factor-alpha (TNF- α), interleukin-6, soluble receptors of interleukin-2, and blood neopterin concentrations were determined in 21 HPN patients and 10 healthy controls. Brain magnetic resonance imaging (MRI) and carefull neurologic clinical examination were performed in 11 patients. Results: Mn concentration was higher in HPN patients than controls (1.96±1.1 vs 0.81± 0.4μg/L;P<0.001) and positively correlated to the amount of parenteral nutrition (PN) supply, transaminases and alkaline phosphatase (r=0.53, P<0.0001) concentrations, as well as to ESR (r=0.61,P<0.0001), TNF- α and blood neopterin. The amount of calories provided by PN was positively correlated to inflammatory markers and liver parameters. All patients investigated by MRI showed hyperintense basal ganglia on T1-weighted images suggesting brain Mn deposition. Only one had slight clinical extrapyramidal symptoms. Conclusion: In HPN patients, sustained inflammation may facilitate hypermanganesemia through 1. cholestatic liver disease and thereby decreased Mn biliary excretion, 2. high nutritional requirements (responsible for increased Mn supply), and/or 3. modified Mn metabolism or body distribution. Neurologic complications appeared marginal whereas Mn brain deposition seems frequent.