CP25 - Viral Meningitis

Question 1

what is meningitis?

Answer 1

inflammation of the meninges

Question 2

what is encephalitis?

Answer 2

inflammation of the brain

Question 3

what is meningo-encephalitis

Answer 3

inflammation of the brain and meninges

Question 4

what are some clinical presentation for meningitis?

Answer 4

WCC >5mm3 in CSF

-ve bacterial culture of the CSF

Question 5

what can cause acute meningitis

Answer 5

Partially treated bacterial meningitis 
Listeria
TB
Syphilis
Malignancy
Autoimmune conditions 
Drugs

Question 6

what are some of the common cause of viral meningitis?

Answer 6

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

Question 7

pathogenesis of viral meningitis?

Answer 7

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

Question 8

what are some clinical presentation of viral meningitis

Answer 8

fever, ‘meningism’, sometimes viral prodrome

Question 9

what is meninigism?

Answer 9

headache, neck stiffness, photophobia

Question 10

what are the most prominent clinical features of viral meningitis?

Answer 10

infant/neonates meningeal sings may be absent

look for nuchal rigidity & bulging anterior fontanelle

Question 11

what are some physiological examinations which can be conducted for viral meningitis?

Answer 11

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

Question 12

what are some of the investigations which can be used to investigate viral meningitis

Answer 12

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

Question 13

what are the result for investigation for viral meningitis?

Answer 13

WCC (pleocytosis = WC in CSF), elevated lymphocytes, neutrophils

proteins - normal, mildly elevated

glucose (ration of CSF:plasma) - normal (50-60%), normal or slight low

Question 14

what are the difference in term of investigation result for viral and bacterial

Answer 14

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

Question 15

what are other investigation techniques can be used to investigate viral meningitis?

Answer 15

throat swab/stool sample - enterovirus PRC

serology - mumps, EBV/CMV, HIV

Question 16

what is the treatment for viral meningitis?

Answer 16

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

Question 17

what is commonest cause of viral meningitis

Answer 17

enteroviral meningitis

Question 18

what are some specific symptoms for enteroviral meningitis

Answer 18

fever, vomiting, anorexia, rash, URT symptoms common

Question 19

what are the treatment for enteroviral meningitis?

Answer 19

no specific treatment and full recovery normal

Question 20

what is the 2nd commonest cause of viral meningitis?

Answer 20

HSV 2

Question 21

is it usual to have viral meningitis from VZV?

Answer 21

not really, but can happen during chickenpox, shingles or after vaccination

Question 22

what are the specific symptoms for mumps meningitis

Answer 22

abdo pain, orchitis, CNS symptoms might happen 5 days after onset of parotitis

Question 23

what condition can have viral meningitis as part of their primary infection?

Answer 23

HIV infection

Question 24

what are some specific symptoms for HIV meningitis ?

Answer 24

fever, lymphadenopathy, pharyngitis, rash (like glandular fever)

Question 25

what some of the causative agents for viral encephalitis?

Answer 25

HSV (1&2)(90% HSV1), VZV, EBV, CMV, measles, mumps, enteroviruses (including polios)

Question 26

what are some of the major clinical presentation of viral encephalitis

Answer 26

altered mental state (confusion/bizarre behaviour - coma), fever, headache, meningism, seizures

Question 27

how can viral encephalitis be distinguish from hydrocephalitis

Answer 27

hydrocephalitis - low GCS

Question 28

what are some investigation available for viral encephalitis?

Answer 28

blood test, CT (necessary before LP), MRI (see typical changes for HSV encephalitis), LP (microscopy, culture, protein/glucose, viral PCR), EEG (In HSV encephalitis 75% will show abnormal temporal lobe activity)

Question 29

what is the treatment for viral encephalitis

Answer 29

high dose IV aciclovir - start on clinical suspicion

Question 30

what is acute disseminated encephalomyelopathy

Answer 30

immune-mediated CNS demyelination, clinical presentation same as encephalitis with same CSF findings