How do I differentiate between viral and bacterial meningitis in a primary care context?

In a primary care setting, differentiating viral from bacterial meningitis relies primarily on clinical assessment, as definitive diagnostic tests like lumbar puncture and cerebrospinal fluid (CSF) analysis are usually performed in secondary care.

• Suspect bacterial meningitis strongly if the patient presents with the red flag combination of symptoms: fever, headache, neck stiffness, and altered level of consciousness or cognition (including confusion or delirium) NICE NG240.
• Viral meningitis often presents with less severe symptoms and may lack the red flag signs seen in bacterial meningitis. However, early symptoms can overlap, making clinical distinction challenging NICE NG240.
• In primary care, if bacterial meningitis is suspected, urgent hospital referral is essential for further investigations including blood tests and lumbar puncture to confirm diagnosis and differentiate from viral causes NICE NG240.
• Blood tests such as white blood cell count, C-reactive protein (CRP), and procalcitonin (PCT) can support suspicion of bacterial infection but normal results do not exclude bacterial meningitis NICE NG240.
• Viral meningitis typically has a more benign course and does not require immediate antibiotic treatment, unlike bacterial meningitis which requires urgent intravenous antibiotics NICE NG240,NICE CKS.
• In summary, in primary care, the presence of the red flag symptoms should prompt urgent hospital referral for suspected bacterial meningitis, while less severe symptoms may suggest viral meningitis but still require careful assessment and safety netting NICE NG240,NICE CKS.