Viral meningitis/Encephalitis Flashcards
(51 cards)
What is the definition of Meningitis?
inflammation of the meninges
What is the definition of Encephalitis?
inflammation of the brain
What is the definition of Meningo-encephalitis?
inflammation of brain and meninges
What is the microbiology of Aseptic Meningitis?
White cell count >5x106/L in CSF - allowed to be higher in children Negative bacterial culture of the CSF
What causes Aseptic Meningitis apart from viruses?
Bacteria e.g. TB, Syphilis non infectious agents e.g. malignancy, drugs etc.
What is the name of a Basic infectious virus particle?
virion
What does the Simple virus structure consist of?
Nucleic acid Capsid - protein coat possibly lipid envelope possibly other proteins/enzymes
Who is Viral Meningitis most common in?
neonates Around the age of 5 More common that bacterial meningitis
What is the leading cause of Viral Meningitis?
Enteroviruses e.g. echovirus HSV2
What is important to ask about in Viral Meningitis?
travel history sexual history check if the patient is immunocompromised
How does the virus enter the CNS?
Via cerebral microvascular endothelial cells Via choroid plexus epithelium from blood Spread along the olfactory nerve
What are the general Clinical features of Viral Meningitis in adults?
Fever Headache Neck stiffness Photophobia Sometimes ‘viral’ prodrome (e.g. lethargy, myalgias, arthralgias, sore throat, Diarrhea And Vomiting, rash)
What are the Clinical features of Viral Meningitis in children?
In neonates/infants meningeal signs may be absent Look for nuchal rigidity (neck stiffness) and bulging anterior fontanelle - sign of increased intercranial pressure
What are the two Examination signs for meningitis?
Kernig’s sign - hip and knee flexed to 90 degrees, the knee cannot be extended Brudzinski’s sign Flexing the neck causes the hips and knees to flex
What is the first investigation that should be carried out when suspecting meningitis?
Lumbar Puncture
When is the only time that care should be taken before doing a Lumbar Puncture for meningitis?
suspected raised inter-cranial pressure removing csf = herniation of the brain through the foramen magnum - can cause arrest perform CT head to check suspecting viral encephilitis
What are the CSF findings of Lymphocytes in viral meningitis?
Lymphocytic, usually
What does Pleocytosis stand for?
white cells in CSF
What are the CSF findings of protein in viral meningitis?
Protein (0.2-0.4 g/L) Normal, mildly elevated (0.5-1.0)
What are the CSF findings of Glucose in viral meningitis?
(ratio of CSF:plasma) Normal ratio is 50-66% In viral meningitis it is normal, or slightly low
What are the CSF differences to distinguish between bacterial and viral meningitis?
↑ opening pressure in bacterial ↑↑ WBC in bacterial ↑ protein in bacterial ↑ glucose in viral bacterial = gram stain
When is it useful to do a Throat swab and/or stool sample?
for enterovirus/ anything transmitted by a faecal oral route
What are the treatment options for meningitis?
Start appropriate IV antibiotics (e.g. cefotaxime) if any risk of bacterial meningitis - after LP preferred Mainly supportive therapy NOTIFIABLE - inform local public health dept
What time of the year does the enteroviral epidemic occur?
late summer/autumn
