Viral Infection Of CNS Flashcards
(50 cards)
What are the three main types of viral CNS infections?
Viral meningitis, viral encephalitis, and viral myelitis.
What are the common symptoms of viral meningitis?
Fever, headache, photophobia, neck stiffness, vomiting, and muscle aches.
What are the common symptoms of viral encephalitis?
Fever, headache, seizures, confusion, agitation, hallucinations, and paralysis.
What are the common symptoms of viral myelitis?
Weakness, sensory disturbances, paralysis, and autonomic dysfunction.
What is meningoencephalitis?
A condition where both the meninges and brain parenchyma are inflamed, leading to overlapping symptoms of meningitis and encephalitis.
What are the major risk factors for viral CNS infections?
No or under-immunization, extremes of age, immunosuppressive diseases, chronic medical conditions, pregnancy, and geographic location.
What are the most common viral causes of CNS infections?
Enteroviruses, herpes simplex virus (HSV), varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), and arboviruses.
Which virus is the most common cause of viral meningitis?
Enteroviruses (accounting for 70-90% of cases).
What is the most common cause of viral encephalitis?
Herpes simplex virus (HSV), particularly HSV-1.
Which viral CNS infection is associated with insect bites?
Arboviruses, such as West Nile virus, Japanese encephalitis virus, and Dengue virus.
What is the primary route of transmission for herpes simplex virus CNS infections?
Direct contact with infected bodily fluids or through reactivation of latent virus in the nervous system.
Which viral CNS infection is associated with newborns?
Neonatal herpes simplex virus (HSV) infection acquired during birth.
Which seasonal viral infections can cause CNS infections?
Flaviviruses such as Japanese encephalitis virus (JEV), West Nile virus (WNV), and Dengue virus (DENV).
How does viral meningitis differ from bacterial meningitis?
Viral meningitis usually has a milder course, with lymphocytic predominance in CSF and normal glucose levels.
How does encephalitis differ from meningitis?
Encephalitis affects brain parenchyma and presents with altered mental status, seizures, and neurological deficits, while meningitis primarily causes meningeal irritation.
What is the main diagnostic test for viral CNS infections?
Lumbar puncture with cerebrospinal fluid (CSF) analysis and polymerase chain reaction (PCR) testing.
What are contraindications to lumbar puncture?
Evidence of increased intracranial pressure, brain mass lesion, coagulopathy, or local skin infection.
Which imaging modality is preferred for viral encephalitis?
Magnetic resonance imaging (MRI) due to its higher sensitivity in detecting early cerebral changes.
What are the characteristic MRI findings in herpes simplex encephalitis?
Edematous changes in the orbital surfaces of the frontal lobes and medial temporal lobe.
What is the most sensitive test for diagnosing herpes simplex encephalitis?
CSF polymerase chain reaction (PCR) for HSV DNA.
What CSF findings suggest viral meningitis?
Normal or slightly elevated opening pressure, lymphocytic pleocytosis, normal glucose, and mildly elevated protein.
What CSF findings suggest bacterial meningitis?
Increased opening pressure, high WBC count (predominantly neutrophils), low glucose, and high protein.
What is the first-line antiviral treatment for herpes simplex encephalitis?
Intravenous acyclovir.
How soon should antiviral therapy be started for suspected HSV encephalitis?
Ideally within 6 hours of presentation to improve outcomes.
