Subcortical Structure Disruption in Diffusion Tensor Tractography of the Patient With the Syndrome of Irreversible Lithium-Effectuated Neurotoxicity Combined With Neuroleptic Malignant Syndrome: A Case Report

Lithium can cause not only acute neurotoxicity but also chronic and persistent neurotoxicity known as syndrome of irreversible lithium-effectuated neurotoxicity (SILENT). The combined use of lithium and antipsychotics increases the possibility of SILENT. Neuroleptic malignant syndrome (NMS) is a reversible, idiosyncratic, and potentially life-threatening reaction, which is usually caused by antipsychotics and other agents, such as mood stabilizers (eg, lithium and metoclopramide). Neuroleptic malignant syndrome is characterized by hyperpyrexia, muscle rigidity, and altered mental status. We describe a case of SILENT combined with NMS in this case report. CASE REPORT: A 46-year-old man who had been treated with lithium for bipolar II disorder since 2008 was prescribed lorazepam, lithium, and aripiprazole at his last outpatient visit. The patient experienced financial difficulties (bankruptcy) and suffered severe emotional stress. Subsequently, he overused lorazepam, lithium, and aripiprazole. Two days after the overdose, he experienced a high fever, confused mental status, and rhabdomyolysis and was diagnosed with NMS. However, even after resolution of NMS-related symptoms, quadriplegia, visual field defects, ataxia, and severe dysarthria persisted. A positron emission tomography-computed tomography brain scan showed decreased (15)F-fludeoxyglucose uptake in bilateral primary motor cortices and in the thalamus, midbrain, and cerebellum. Brain magnetic resonance imaging diffusion tensor imaging and diffusion tensor tractography of the subcortical tracts revealed structural disruptions, especially in the corticospinal tract, dentatorubrothalamic tract, and optic radiation, which seemed to be correlated with the clinical symptoms of the patient. CONCLUSION: This case suggests that the clinical use of diffusion tensor tractography could be helpful to explain the clinical features in the case of SILENT combined with NMS.