Meningitis is an infection of the membranes (meninges) surrounding the brain and spinal cord. It can be caused by bacteria, viruses, or fungi. Bacterial meningitis is the most common and life-threatening type. Symptoms include fever, severe headache, nausea, and neck stiffness. Diagnosis involves spinal fluid analysis to identify the cause. Treatment focuses on antibiotics, steroids, and managing increased intracranial pressure. Complications may include hearing loss, learning difficulties, and seizures. Prevention involves vaccination and prompt treatment of infections.