aseptic meningitis syndrome characterized by headache, neck stiffness, low grade fever, and Cerebro Spinal Fluid lymphocytic pleocytosis in the absence of an acute bacterial pathogen; often used synonymously with viral meningitis, but also incudes meningeal inflammation due to various drugs (e.g., NSAIDs) or diagnostic procedures (e.g., angiography); atypical bacterial, fungal, parasitic, or parameningeal infection; neoplastic processes; and various systemic disorders