CP25 - Viral Meningitis Flashcards
what is meningitis?
inflammation of the meninges
what is encephalitis?
inflammation of the brain
what is meningo-encephalitis
inflammation of the brain and meninges
what are some clinical presentation for meningitis?
WCC >5mm3 in CSF
-ve bacterial culture of the CSF
what can cause acute meningitis
Partially treated bacterial meningitis Listeria TB Syphilis Malignancy Autoimmune conditions Drugs
what are some of the common cause of viral meningitis?
enterovirus - leading cause eg echoviruses, coxsakie virus, parecho virus
Herpes Simplex Virus 2 (HSV 2 more than HSV 1)
CMV, EBV (Epstein Barr Virus)
Mumps virus
HIV
influenza
pathogenesis of viral meningitis?
Colonisation of mucosal surfaces
Invasion of epithelial surface
Replication in cells
Dissemination and CNS invasion - via cerebral microvascular endothelial cells, choroid plexus epithelium, spread along the olfactory nerve
what are some clinical presentation of viral meningitis
fever, ‘meningism’, sometimes viral prodrome
what is meninigism?
headache, neck stiffness, photophobia
what are the most prominent clinical features of viral meningitis?
infant/neonates meningeal sings may be absent
look for nuchal rigidity & bulging anterior fontanelle
what are some physiological examinations which can be conducted for viral meningitis?
Kernig’s sign - With hip and knee flexed to 90o, the knee cannot be extended due to pain/stiffness in the hamstrings
Brudzinski’s sign - Flexing the neck causes the hips and knees to flex
Nuchal rigidity =
Resistance to flexion of the neck
what are some of the investigations which can be used to investigate viral meningitis
blood test
CT head - look for evidence of raised intra-cranial pressure and alternative diagnosis
suitable for LP as in certain cases, intracranial pressure present and contraindicated for LP
LP - microscopy, culture, sensitivity, protein, glucose, viral PCR: enteroviruses, HSV, VZV
what are the result for investigation for viral meningitis?
WCC (pleocytosis = WC in CSF), elevated lymphocytes, neutrophils
proteins - normal, mildly elevated
glucose (ration of CSF:plasma) - normal (50-60%), normal or slight low
what are the difference in term of investigation result for viral and bacterial
CSF finding
bacterial - opening pressure increase, viral same
WBC - elevated dramatically in bacterial only mild in viral
protein - elevated dramatically in bacterial only mild in viral
glucose - decrease in bacterial, only slightly decrease in viral
what are other investigation techniques can be used to investigate viral meningitis?
throat swab/stool sample - enterovirus PRC
serology - mumps, EBV/CMV, HIV
what is the treatment for viral meningitis?
Start appropriate IV antibiotics (e.g. cefotaxime) if any risk of bacterial meningitis
No evidence to support use of any specific treatment in viral meningitis (though some treat HSV and VZV with aciclovir)
inform local public health dept
what is commonest cause of viral meningitis
enteroviral meningitis
what are some specific symptoms for enteroviral meningitis
fever, vomiting, anorexia, rash, URT symptoms common
what are the treatment for enteroviral meningitis?
no specific treatment and full recovery normal
what is the 2nd commonest cause of viral meningitis?
HSV 2
is it usual to have viral meningitis from VZV?
not really, but can happen during chickenpox, shingles or after vaccination
what are the specific symptoms for mumps meningitis
abdo pain, orchitis, CNS symptoms might happen 5 days after onset of parotitis
what condition can have viral meningitis as part of their primary infection?
HIV infection
what are some specific symptoms for HIV meningitis ?
fever, lymphadenopathy, pharyngitis, rash (like glandular fever)
