Cytotoxic Lesion of the Corpus Callosum in a Patient with Acute-on-chronic Lithium Toxicity.

A 30-year-old woman with history of bipolar disorder presented to the emergency department with impaired consciousness and myoclonus following regular lithium treatment. Brain magnetic resonance imaging revealed a hyperintense lesion in the splenium of the corpus callosum, consistent with cytotoxic lesions of the corpus callosum (CLOCCs). Serum lithium levels were markedly elevated (3.54 mmol/L), and acute-on-chronic lithium toxicity was diagnosed. Hemodialysis and supportive care resulted in clinical and radiological recovery. This case highlights that CLOCCs may serve as important neuroimaging evidence of lithium toxicity and may support an early diagnosis and treatment, especially in patients with long-term lithium use.