Reversible splenial lesion syndrome induced by paracetamol and lithium: two case reports

Abstract Background: Reversible splenial lesion syndrome (RESLES) is a rare neurological syndrome characterized by a reversible lesion in the splenium of the corpus callosum (SCC). Various etiologies, such as infection, high-altitude cerebral edema, seizures, antiepileptic drug (AED) withdrawal, and metabolic abnormalities, are involved in the development of RESLES. However, few studies have reported the occurrence of this disorder associated with medications, particularly paracetamol, which has not yet been documented. Case presentation: A 50-year-old man with neuropsychiatric symptoms who was receiving increased doses of paracetamol was referred to our hospital. The patient fully recovered 8 days after treatment. The second case involved a 35-year-old female who received 1500 mg/day lithium and 500 mg/day quetiapine for bipolar disorder (BD). She experienced generalized tremor, rigidity, dysarthria, high fever, hypertension, tachycardia, and tachypnea. Symptoms and brain lesions fully resolved two weeks after discontinuation of lithium. Brain magnetic resonance imaging (MRI) in both patients typically demonstrated a reversible lesion with transiently reduced diffusion in the SCC. Conclusion: RESLES is a rare finding that is usually incidentally detected. Therefore, MRI should be performed to evaluate SCC in patients taking excessive medication who present with neuropsychiatric symptoms.