Metronidazole-induced encephalopathy in a patient with primary Sjögren disease

Primary Sjögren disease is a chronic autoimmune disorder that impairs the peripheral and central nervous systems. No cases of metronidazole (MNZ)-induced encephalopathy (MIE) in patients with primary Sjögren disease have been reported. Herein, we present the case of a patient with primary Sjögren disease who developed MIE. A 74-year-old woman with a history of primary Sjögren disease and interstitial lung disease presented with progressive gait disturbance and dysarthria after prolonged MNZ administration. In addition, the patient had right facial palsy and ataxia of the trunk and extremities. Diffusion-weighted brain magnetic resonance imaging revealed symmetric hyperintense signals in the splenium of the corpus callosum and bilateral dentate nuclei, which were suggestive of MIE. MNZ was immediately discontinued, leading to rapid improvement in neurological impairments. Additionally, improvement in intracranial lesions was observed on brain magnetic resonance imaging. To our knowledge, this is the first reported case of MIE in a patient with primary Sjögren disease. Our case suggests the importance of a comprehensive investigation of the causes of neurological manifestations in patients with primary Sjögren disease, while considering other autoimmune diseases and drug induction.