Explore the latest updates on diagnosing meningitis and encephalitis in this comprehensive physician grand rounds presentation. Delve into essential topics including CNS infection definitions, blood-brain barrier basics, and typical time courses of neurologic disorders. Examine community-acquired meningitis recognition, etiologies, and microbiology based on risk factors and presentation. Compare disease recognition between encephalitis and meningitis, focusing on major pathogens and diagnostic clues. Learn about HSV encephalitis clinical presentation and general principles of diagnostic approaches for CNS infections. Discover time-sensitive strategies for bacterial meningitis diagnosis, including physical examination, lumbar puncture, CSF examination, and neuroimaging techniques. Explore newer molecular diagnostics, including multiplex PCR, and understand their limitations in revolutionizing CNS infection diagnosis.