Viral meningitis and encephalitis Flashcards Preview

Clinical Pathology > Viral meningitis and encephalitis > Flashcards

Flashcards in Viral meningitis and encephalitis Deck (24):
1

What is meningitis?

Inflammation of meninges

2

What is encephalitis?

Inflammation of brain tissue

3

What is meningoencephalitis?

I nflammation of meninges and brain tissue

4

What is aseptic meningitis?

Clinical picture of meningitis observed (i.e. increased lymphocytes, increased protein, normal/reduced glucose)

BUT negative bacterial culture

5

What is the main cause of aseptic meningitis?

Viruses mainly but also..
- listeria
- TB
- Syphilis (can not be grown in culture)

6

What group of people is viral meningitis most common in?

Children/neonates

7

What are the main viruses that cause viral meningitis?

1/3 cases = unknown
Enteroviruses e,g echovirus, coxsackie
- herpes viruses - HSV, EBV, VZV, cytomegalovirus
- Mumps virus
- HIV

- Measles
-Influenza/parainfluenza

8

Which herpes simplex virus is more associated with meningitis?

HSV II

9

What is the pathogenies of viral meningitis (i.e. how does it occur?)

Colonisation of mucosal surfaces

invasion of epithelial cells

Replication in cells

Dissemination and invasion in CNS - blood/nerves

10

What are the clinical features of viral meningitis?

- Very similar to bacterial!
- Fever
- -/+ rash (unusual)
- 'Meningism' i.e. headache, neck stiffness, photophobia

- Sometimes viral prodrome i.e. evidence of previous viral infection

11

What to look out for in infant viral meningitis?

Meningeal signs might be absent
- Nuchal rigidity (neck stiffness)
- Bulging anterior fontanelle (increasing intracranial pressure)

12

what is the Kernigs sign?

With hips and knee flexed at 90 degrees, cannot extend knee due to pain/stiffness in hamstrings

13

What is the Brudzinski's sign?

Flexing the neck (pain) will cause the hips and knees to flex

14

What is nuchal rigidity?

Resistance to flexion of neck

15

What investigations should you perform?

Blood - FBC, U&E, CRP, clotting
CT scan (maybe)
Lumbar puncture
- Microscopy
- Glucose (CSF:Plasma)
- Protein
- PCR

16

What is pleocytosis?

White blood cells in CSF

17

What are the CSF features with viral meningitis?

- Lymphocytes in CSF approx 500 (polymorphs i..e neutrophils maybe in first 24hrs)

- Normal/reduced glucose (CSF:Plasma ratio; usually 50-66%)

- Increased protein (0.5-1.0; normal - 0.2-0.4)

18

What is the treatment for viral meningitis?

Start appropriate IV antibiotics (risk of bacterial meningitis e.g. cefotoxime)

No evidence for use of antivirals (e.g. aciclovir) for viral meningitis - supportive therapy

19

Which HSV, HSVI or II, is more commonly associated with meningitis?

HSVII (genital warts and meningitis) - meningitis can follow genital lesions

HSVI (cold sores and viral ENCEPHALITIS)

20

What are the main cause of viral encephalitis?

Herpes simplex virus I and II (90% are HSV I)

VZV, CMV, EBV
Measles
Mumps
Enterovirus (inc polio)
HIV

Other causes - acute disseminated encephalomyopathy (ADEM)

21

What are the clinical features of viral encephalitis?

**Altered mental state (bizarre/abnormal behaviour)** (Not in meningitis)

Fever
Headache
Meningism (may be absent)

+/- focal neurological symptoms
e.g. seizures**, weakness, dysphagia/asphasgia, CN palsy, ataxia

22

What investigations should be performed for viral encephalitis?

- Blood tests
- CT BEFORE LP
- MRI - see changes typical of HSV
- Lumbar puncture - microscopy, protein, glucose, viral PCR

23

What is the treatment for viral encephalitis?

Focused on HSV encephalitis

Aciclovir

24

What is acute disseminated encephalomyelopathy? (ADEM)

Immune mediated CNS demyelination following viral illness or vaccination

CSF findings are same as viral meningitis

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