Microbiology: CNS Infections

Question 1

5-tiers for DDx of viral meningoencephalitis

Answer 1

Group 1 pathogens (always investigate)
• HSV1, 2
• VZV
• Enterovirus
• JEV in patients with encephalitis —> need IgM serology
• Parechovirus in infants (cousin of enterovirus)

Group 2 (always consider in children, young adults)
• Respiratory viruses: Influenza, Adenovirus, etc.
• Other herpesviruses: Primary EBV, Primary CMV, Primary HHV-6

Influenza: acute necrotising encephalitis
• trigger unusual encephalopathy syndrome

Group 3 (consider if there is compatible history)
• Travel: encephalitogenic arboviruses endemic to areas of travel
• Animal contact: Rabies, Herpes B (monkey B), LCMV, Nipah
• Previous residence in UK (80s-90s): variant CJD
• Profound immunosuppression: JC PML, CMV encephalitis, HHV-6 encephalitis, HIV encephalopathy, astroviruses, bornaviruses

Group 4
• Exanthematous disease viruses (Maculopapular rash)
• Mumps
• Hep E

Group 5
• severe arbovirla infections: dengue, Zika, chikungunya, yellow fever
• Viral haemorrhagic fever
• Reye’s syndrome
• Rotavirus