3: CNS infections Flashcards Preview

Neurology Week 3 2018/19 > 3: CNS infections > Flashcards

Flashcards in 3: CNS infections Deck (51)
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1
Q

What are consequences of untreated CNS infections?

A

Brain herniation (Monro Kellie)

Cord compression and necrosis

2
Q

What is the difference between meningitis and encephalitis?

A

Meningitis - meninges affected only

Encephalitis - diffuse infection of brain tissue

3
Q

What is the difference between encephalitis and encephalopathy?

A

Encephalopathy - broader term meaning any disease of the brain

4
Q

What does aseptic meningitis mean?

A

No bacteria isolated from culture after two days

Could mean inflammation has viral/other origin

5
Q

Chronic CNS infections are common in people who are ___.

What is an example?

A

immunosuppressed

TB

6
Q

Why are brain abscesses particularly dangerous?

A

Focal area of pus in the brain

causing FOCAL SYMPTOMS

7
Q

What is pyogenic meningitis?

A

Meningitis caused by purulent bacteria

8
Q

What does Strep. pneumoniae look like on a Gram film?

A

Gram positive cocci in chains

9
Q

What does Meningococcus look like on a Gram film?

A

Encapsulated Gram -ve cocci

10
Q

What does Listeria monocytogenes look like on a Gram film?

A

Gram positive bacilli

11
Q

What does H influenzae look like on a Gram film?

A

Gram negative bacillus

12
Q

What is the second most common type of meningitis after bacterial?

A

Viral meningitis

13
Q

When in the year does viral meningitis tend to present?

A

Late summer

14
Q

How is viral meningitis investigated?

A

Pharyngeal swab for viral PCR

Stool sample (for enterococcus)

15
Q

What are the important viruses which cause meningitis?

A

Enterococcus

HSV

Mumps (in countries which aren’t vaccinated for it)

16
Q

How does meningitis tend to present?

A

Fever

Headache

Neck stiffness

+/- meningococcal rash

17
Q

What is the difference between the presentations of meningitis and encephalitis?

A

Meningitis - classic triad of headache, fever and neck stiffness

Encephalitis - diffuse infection, so widespread mental state changes +/- sepsis

18
Q

Neck stiffness tends to be a feature of (meningitis / encephalitis).

A

meningitis

19
Q

What virus should you worry about in people presenting with encephalitis?

A

HSV

20
Q

Which treatment is given for suspected encephalitis?

A

Aciclovir IV

21
Q

Which imaging modality is helpful in diagnosing encephalitis?

A

MRI brain

22
Q

Which organisms should you strongly suspect in patients with bacterial meningitis?

A

Neisseria meningitidis / Meningococcus - most common, accompanied by a rash

Strep. pneumoniae - next most common

Listeria monocytogenes - in those > 60, immunosuppressed

H. influenzae - in children who haven’t been vaccinated

23
Q

How do most cases of bacterial meningitis start?

A

Colonisation of nasopharynx by meningococcus

24
Q

What is the gold standard investigation for bacterial meningitis?

A

Lumbar puncture –> CSF culture

25
Q

In bacterial meningitis, CSF white blood count is raised.

Which value is typical of bacterial meningitis?

A

>2000

26
Q

In bacterial meningitis, CSF glucose conc. will be (more than / less than) that of blood glucose.

A

less than

because the bugs are munching it

27
Q

Which investigation amplifies the amount of bug present and helps you to identify the causal agent of a meningitis?

A

PCR

28
Q

Where does meningococcus colonise?

A

Nasopharynx

29
Q

What is a cutaneous sign of meningococcal septicaemia?

A

Widespread, non-blanching purpuric rash

30
Q

Why is H influenzae meningitis much less common nowadays?

A

Vaccination

31
Q

Who tends to get Strep meningitis?

A

Kids

Hospitalised patients

Patients with cochlear implants

32
Q

Who tends to get Listeria meningitis?

A

Older patients (>60)

Immunosuppressed

33
Q

What is the antibiotic of choice for

a) meningococcal / Strep
b) Listeria

meningitis?

A

a) Ceftriaxone
b) Ceftriaxone + Amoxicilin (latter is the effective one, keep cef until you eliminate the others)

34
Q

What are some causes of aseptic meningitis?

A

Viral infection

Irritation of meninges by infection elsewhere

Amoebic meningitis

Chemical-induced

Behcets syndrome

Drugs

35
Q

What is the antibiotic of choice for bacterial meningitis?

A

Ceftriaxone

(Chloramphenicol if allergic)

36
Q

What is given alongside Ceftriaxone for most cases of bacterial meningitis?

A

Dexamethasone

proven to help in Strep infection, if confirmed not Strep, stop it

37
Q

Which antibiotic is ADDED in suspected Listeria infection?

A

Amoxicillin

38
Q

Meningitis is a ___ disease, meaning any new cases must be reported to ___ ___.

A

notifiable

Public Health

39
Q

What is given as prophylaxis for bacterial meningitis?

A

Vaccination

40
Q

How do bacteria reach the meninges?

A

Direct spread from nasopharynx

Invasion from other sites of trauma/infection e.g sinuses, fractures

Invasion via bloodstream

41
Q

What are the symptoms of meningitis?

A

Fever

Headache

Neck stiffness

(In meningococcal infections there may be a widespread purpuric rash)

42
Q

What is Kernig’s sign?

A

If patient is lying supine and asked to extend knee from 90 degree flexion, they won’t be able to

Physically demonstrable sign of meningitis

43
Q

As meningitis progresses, patients experience ___ symptoms like photophobia and a reduced conscious level.

A

neurological symptoms

44
Q

What biochemical patterns will you see on lumbar puncture of someone with acute bacterial meningitis?

A

Raised WBC and neutrophils

Raised protein

Low CSF glucose

45
Q

What biochemical patterns will you see on lumbar puncture of someone with viral meningitis?

A

No Gram results (not bacteria)

Normal glucose

46
Q

What biochemical patterns would you see on lumbar puncture of a patient with chronic tuberculous meningitis?

A

Raised WBC and lymphocytes (chronic inflammation)

Raised protein

Reduced CSF glucose (because the bugs are using it)

47
Q

Which antibiotic is given first line for bacterial meningitis?

A

Ceftriaxone IV

2g BD

48
Q

Which antibiotic is given first line for suspected bacterial meningitis if a patient is allergic to beta lactams?

A

Chloramphenicol

49
Q

What drug is given to every patient with bacterial meningitis in addition to ceftriaxone?

Why?

A

Dexamethasone

Proven to improve outcomes in Strep. pnuemoniae infection, if another bug cultured you would stop it

50
Q

For bacterial meningitis, which drug is added to ceftriaxone + dexamethasone if a patient is > 60 or immunocompromised?

Why?

A

Amoxicillin

Ceftriaxone isn’t effective on Listeria

51
Q

Which drug is given first line for suspected viral meningitis?

A

Aciclovir IV