[A Case of Legionella Pneumonia Causing Neurological Symptoms Related to a Reversible Corpus Callosum Lesion].

A 51-year-old man presented at the emergency department with a one-day history of fever, altered mental status, slurred speech, worsening gait instability, nausea, vomiting, and diarrhea. The patient did not have a history of alcoholism or drug abuse. On physical examination, crackles were heard over the right lower lobe. Neurological findings revealed ataxic gait, dysarthria and bilateral dysmetria upon finger-nose testing. The results of laboratory tests revealed leukocytosis, renal failure, and hyponatremia. Chest radiography and lung computed tomography (CT) revealed right lower lobe infiltrates with air bronchograms. The result of a urinary Legionella antigen test was positive. The results of brain CT and cerebrospinal fluid (CSF) analyses did not reveal any signs of infection, but brain magnetic resonance imaging (MRI) revealed a corpus callosum lesion upon admission. The patient's symptoms began to resolve after the administration of intravenous levofloxacin. A subsequent brain MRI examination performed 9 days after admission showed the complete resolution of the lesion. He was discharged 11 days after admission without any neurological sequelae. He was finally diagnosed as having clinically mild encephalitis/ encephalopathy with a reversible splenial lesion (MERS).