Viral CNS infections


CT before LP

• Altered mental status (GCS <12 or drop in GCS of ≥2)
• Immune deficiency
• Papilledema
• Focal neurologic deficit
• CSF shunt
• Hydrocephalus
• CNS trauma
• History of neurosurgery or a space-occupying lesions
• Signs or symptoms of parameningeal infection or tumor
  

Aseptic (Viral) Meningitis

• More common than bacterial meningitis
• Negative bacterial cultures
• May be viral, parasitic, medication-related (NSAID’s, ABX, anti-Sz), vasculitis, neoplasm
• Enteroviruses account for the majority of cases of viral meningitis (85-95%)
  
• Arbovirus
• St. Louis encephalitis and West Nile virus
  
• Eastern equine encephalitis and Western equine encephalitis
  
• California encephalitis
  
• Also parechoviruses, Herpesviruses, Lyme
  

Viral encephalitis

• Fever and signs and symptoms of neurologic dysfunction (cranial nerve palsies, seizures, paralysis, dysarthria) and/or altered state of consciousness indicate parenchymal brain involvement

Viral myelitis

• Myelitis involves spinal cord inflammation and is manifest by flaccid paralysis and reduced or absent reflexes