Tacrolimus-associated mutism after orthotopic liver transplantation

Background. Mutism/speech apraxia has been well documented as a toxic effect of cyclosporine after liver transplantation but has been reported only rarely with tacrolimus. Brain imaging with magnetic resonance or computed tomography has failed to demonstrate abnormalities in affected patients. Methods. We present the first example of an acute onset of loss of speech associated with a sudden elevation of serum tacrolimus level after successful orthotopic liver transplantation. We also describe the positron emission tomography (PET) scan of this patients brain. Results. PET scan imaging of the brain was abnormal, demonstrating decreased metabolism in the posterior temporo-parieto-occipital regions. Statistical probability mapping revealed additional areas of hy pometabolism in the cingulate gyrus. Conclusions. PET scan revealed abnormalities of the brain in a patient with tacrolimus-induced mutism. The cingulate gyrus may play a role in the mutism/speech apraxia syndrome seen with cyclosporine/tacrolimus neurotoxicity.