Trace elements and flapping tremors in patients with liver cirrhosis. Is there a relationship?

Objective: To investigate the possible correlation between hepatic flapping tremors and serum manganese Mn, iron Fe, zinc Zn, and copper Cu.
Methods: This case control study was carried out in Assiut University Hospital, Assiut, Egypt from June 2006 to June 2007. It included 100 patients with liver cirrhosis, 78 had flapping tremor, and 22 had not, and 60 healthy controls. All patients were subjected to assessment of serum Mn, total Fe, total iron binding capacity (TIBC), Zn, and Cu. Assessment of hepatic encephalopathy was carried out using a battery of cognitive function tests. All patients had electroencephalography and MRI of the brain.
Results: Compared to healthy controls, patients showed increase in Mn (p<0.0001), Cu (p<0.05) and decrease in TIBC (p<0.000), Zn (p<0.05). Eighty-two percent of patients had minimal hepatic encephalopathy (mHE). In 85%, MRI-brain showed bilateral hyperintense substantia nigra and globus pallidus on T1-weighted images. A significant positive correlation was present between tremors and severity of liver dysfunction, mHE and serum Cu, and negative correlation with total Fe, TIBC, and Zn.
Conclusion: Altered homeostasis of Mn and other minerals could be responsible for the pathophysiology of cognitive deficits associated with liver cirrhosis, but not with flapping tremors. The exact pathogenic role and possibilities for therapeutic implications need further study.