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[Posterior reversible leukoencephalopathy syndrome in a patient with Parkinson's disease and initial psychiatric symptoms: a complex clinical presentation].

INTRODUCTION
The relevance of the immunosuppressive drug tacrolimus in the prevention of rejection and graft-versus-host disease in transplanted patients is beyond all doubt. However, tacrolimus often has neurotoxic effects, including severe conditions such as posterior reversible leukoencephalopathy syndrome.


CASE REPORT
A 75-year-old male who had undergone a kidney transplantation five years earlier, for which he was receiving treatment with tacrolimus and mycophenolate. He also had advanced Parkinson's disease, treated with several dopamine agonists. The patient visited the emergency department after a week-long history of visual hallucinations, delirium, expansive mood, confusion and headache. The focal psychogeriatric examination revealed psychosis secondary to dopaminergic agonists as the first diagnostic option, without excluding other possible iatrogenic causes despite the tacrolimus being within the therapeutic range (8.3 ng/mL). Both cranial computed tomography, which did not show any significant findings, and a magnetic resonance scan, in which a bilateral parietooccipital oedema was observed, were performed, this latter finding being compatible with posterior reversible leukoencephalopathy syndrome. While the patient was in hospital, tacrolimus was replaced by everolimus, and the dopaminergic medication was adjusted, resulting in a swift and full remission of the clinical signs and symptoms.


CONCLUSIONS
The diagnosis of posterior reversible leukoencephalopathy syndrome should be considered in patients with a history of organ transplantation treated with immunosuppressive drugs who have an acute onset condition with neurological or psychiatric symptoms.