Infectious causes of dementia

Differential Diagnosis

• Bacterial
  • Syphilis, usually as general paralysis with emotional incontinence, irritability, grandiosity, euphoria, poor insight, apathy, delusions, and cognitive impairment
  • Lyme meningoencephalomyelitis, with impaired executive function and reduced attention
  • Sequela of bacterial meningitis
  • Whipple disease
• Viral
  • Viral encephalitis (usually reversible)
    • Herpesviruses, including HSV-1, HSV-2, EBV, HHV-6, HHV-7 (and CMV and VZV, in immunocompromised people)
    • Arboviruses
    • Enteroviruses
  • HIV-associated dementia: motor slowing, depressed mood, impaired recall but not recognition, poor visuospatial skills, and impaired executive function
    • Also, HIV-associated opportunistic infections including toxoplasmosis, cryptococcus, and CMV
  • Hepatitis C virus
  • Measles (subacute sclerosing panencephalitis, SSPE)
• Fungal
  • Cryptococcus
• Parasitic
  • Neurocysticercosis (rarely)
• Prion
  • Creutzfeldt-Jakob disease