Viral Meningitis / Encephalitis (CNS Pathology) Flashcards
What is Meningitis?
Inflammation of the meninges
What is Encephalitis?
Inflammation of the brain
What is Aseptic Meningitis?
Is the inflammtion of the meninges however it is not caused by bacteria. Viruses are usually the cause e.g.syphilis
What is the stucture / components of a virus?
Nucleic Acid:
- DNA or RNA
- Single or double stranded
- circular or linear
Viral Proteins:
-form capsid / membrane projections.
Viral Enzymes:
- replication
- transcription
- protein modification
What is the epidemiology of Viral Meningitis?
-common is children
What are the causes of Viral Meningitis?
1) Enteroviruses
2) Herpes Viruses
3) Mumps
4) HIV
5) Measles
6) Influenza
How do these pathogens cause meningitis?
1) COLONISE on mucosal surfaces
2) ENTER epithelial surface
3) REPLICATE in cells
4) spread and INVADE CNS
What are the clinical features of Meningitis
1) Fever
2) Meningism
- headache
- neck stiffness
- photophobia
***3) bulging anterior fontanelle (top of skull) in infants
What is Kernig’s Sign?
When the hip and knee are both flexed to 90’ the knee cannot be extended further due to pain / stiffness in hamstrings. It is a sign of meningitis.
What is Brudzinki’s sign?
Flexing the neck causes the hips and knees to flex.
What investigations should be done for meningtis?
- Lumbar puncture ASAP alongside blood glucose levels.
- CT scan (raised intracranial pressure)
What are the CSF findings in viral meningitis?
- White Cell count (lymphocytic, neutrophils)
- Protein (0.2 - 0.4 g/L)
- Glucose ratio normal or low.
What is the treatment of meningitis?
-IV antibiotics (if bacterial)
what is the commonest cause of viral meningitis in the uk?
What are the symptoms?
Enteroviral
Symptoms:
-fever, vomiting, anorexia, rash, respiratory tract problems
Which form of Herpes Simplex Virus (HSV) causes meningitis?
HSV2 = meningitis + genital herpes
HSV1 = Encephalitis + cold sores
