A man visited the hospital with fever, myalgia, and vomiting. His systolic blood pressure was below 60 mmHg, and he was admitted to the intensive care unit with the suspicion of septic shock. After admission, Streptococcus pneumonia was found in his blood, and treatment with vancomycin 2 g/day and ceftriaxone 4 g/day was initiated. Following antibiotic treatment for 4 days, his mentation deteriorated to a stupor. Brain magnetic resonance imaging (MRI) indicated hydrocephalus, ventriculitis, and choroid plexitis (Fig. 1). Cerebrospinal fluid (CSF) examination showed normal opening pressure (180 mmHg), pleocytosis (white blood cell count, 280; neutrophils, 55%), high protein level (1,448 mg/dL), and low glucose levels (CSF, 54 mg/dL; serum, 135 mg/dL). Consequently, a high dose of steroids (dexamethasone, 40 mg/day) was prescribed together with antibiotics. After 14 days of antibiotic treatment, his general condition improved.Brain MRI findings depicting pyogenic ventriculitis typically include ependymal thickening and enhancement with T2 prolongation surrounding the ventricle, hydrocephalus, and debris within the dependent aspect of the ventricles [1,2]. In addition, diffusion restriction and swelling of the choroid plexus are suggestive