An Unusual Cause of Ataxia in Patient with Sjogren's Syndrome: Metronidazole Neurotoxicity

Cerebellar ataxia associated with metronidazole is rare. Sjögren's syndrome (SS), a chronic autoimmune disease, can also rarely present with neurological symptoms such as cerebellar ataxia. In this report, we aimed to present a 40-year-old female patient diagnosed with SS who developed acute-onset speech disorder and imbalance. The patient's complaints developed shortly, four days, after taking metronidazole for a vaginal infection. Her neurological examination revealed a broad-based gait, explosive speech, and bilateral dysmetria. Routine blood tests, nerve conduction studies, and cerebrospinal fluid analysis were normal. Brain magnetic resonance imaging showed hyperintensity in the dentate nuclei of the cerebellum, consistent with metronidazole-induced neurotoxicity. The patient's symptoms rapidly improved after discontinuation of the drug, and the lesions had completely resolved on imaging one month later. Apart from neuropathy and cerebellar degeneration, which are the most common etiologies of ataxia in Sjögren's syndrome, rare metronidazole-induced neurotoxicity was observed in our patient. Metronidazole-induced neurotoxicity may be a potentially reversible cause of cerebellar symptoms, and its recognition based on typical radiological features is important for drug withdrawal and complete recovery.