CNS Infections Flashcards

1
Q

Define meningitis

A

Infection in sub arachnoid space of the LEPTOmeninges

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2
Q

Clinical features in infant with meningitis

A

Bulging fontanelle, crying, poor feeding

Non blanching rash

Headache, neck stiffness, fever vomiting etc…

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3
Q

CSF findings in viral meningitis (lymphocytes, neutrophils, glucose, protein)

A

Lymphocytes: High

Neutrophils: Low

Glucose: normal

Protein: Slightly elevated

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4
Q

CSF findings in bacterial meningitis (lymphocytes, neutrophils, glucose, protein)

A

Lymphocytes: Slightly raised

Neutrophils: Very raised

Glucose: Very low

Protein :elevated

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5
Q

CSF findings in TB meningitis (lymphocytes, neutrophils, glucose, protein)

A

Similar to virus except glucose is low and ziel neelson is +ve

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6
Q

Cause of intracellular meningitis?

A

Neisseria meningitidis

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7
Q

Cause of intercellular meningitis?

A

Haem. influenzae

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8
Q

How do neisseria men. and H. influenze overcome the immune system to cause meningitis?

A

Polysaccharide capsules are able to evade complement system in blood

Once in CNS, there is no complement system so they grow unimpeded

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9
Q

How is the BBB broken down in meningitis? (recognise)

A

Bacteria replicate and lyse

This causes release of interleukins IL1, IL6 and TNF

Polymorphs are attracted to infection site

THis causes endothelial disruption, albumin leak, and CEREBRAL OEDEMA!!

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10
Q

Most common causes of meningitis in infants?

A

Group B strep

E coli

Listeria

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11
Q

Most common causes of meningitis in toddlers

A

N. meningitis

Strep pneumoniae

H influenzae

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12
Q

Most common cause of meningitis in adults

A

N. meningitidis

S. pneumoniae

(H. influenzae less common)

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13
Q

What are the ‘NHS’ bacteria?

A

Neisseria meningitis

H. influenzae

Strep pneumonia

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14
Q

Who gets neisseria meningitis? What is it sensitive to?

A

Children and YAs

Penacillin

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15
Q

Who gets H. influenzae? What is it resistant to?

A

Young kids

B lactamase +ve, so penicillin resistant

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16
Q

Who gets strep pneumoniae? What is is resistant to?

A

Extremes of age

Starting to see penicillin resistance

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17
Q

What type of organism is strep pneumoniae? What do you see on blood agar?

A

Gram +ve diplococci

Draughtsman colony, green zone of haemolysis

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18
Q

What type of organism is Haemophilis influenzae?

A

Gram negative rod

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19
Q

Culturing requirements for H influenzae?

A

Needs X and V factors

Grows best on enrichment media eg chocolate agar

Smells like semen lol

Invasive strains are often capsulated.

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20
Q

Diseases caused by H influenzae?

A

Pneumonia

Meningitis

Epiglottitis

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21
Q

What type of organism is neisseria meningitidis?

A

Gram -ve diplococcus

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22
Q

Culturing features of neisseria meningitis?

A

Oxidase positive

IDENTIFIED SUGAR FERMENTATION

MeninGos do Maltose and Glucose!

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23
Q

Treatment of meningitis for adults and children

A

Ceftriaxone (/benzylpenicillin)

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24
Q

Treatment of meningitis in infant?

A

Ampicillin + cefotaxime

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25
Q

What immunotherapy can be used for meningitis?

A

Dexamethasone before antibiotic may decrease cerebral oedema in children

26
Q

What does Hib/menC vaccine protect against?

A

H influenzae and meningococcal meningitis group C

27
Q

Describe Hib vaccine components (recognise_

A

PRP polyribosylribitol phosphate

T cell independent (no IgG boost)

28
Q

New meningitis vaccines? (3)

A

New conjugate meningococcal group C

Meningococcal polysaccharide A, C (not B neisseria)

Pneumococcal 7 valent vaccines

29
Q

Which meningitis is not protected against with vaccines?

A

Group B Neisseria meningitis

30
Q

Prophylaxis for meningitis if there is an unimmunised child under 4 in the household?

A

Rifampicin

31
Q

Prophylaxis for menigitis?

A

Ciprofloxacin for all close contacts in past 10 days

32
Q

Viral causes of meningitis?

A

Enteroviruses -80%

Also:
HSV 2 (and 1)
VSV, CMV
Mups
Adenovirus
HIV
33
Q

Examples of enteroviral causing meningitis?

A

Coxsachie or echovirus most common

34
Q

Treatment of viral meningitis?

A

SUPPORTIVE

Anti-HSV not proven

May be preventable by vaccination

35
Q

Prognosis of viral meningitis?

A

Better than bacterial

36
Q

Non-viral causes of aseptic meningitis? (i.e couldn’t culture anything or use PCR identification)

A
Fungi
TB!!!
Syphillis
Brucella
Mycoplasma
Protozoa
Helminths
37
Q

Age group affected by TB meningitis?

A

<6 yrs

38
Q

How does TB meningitis present?

A

3-6 months after initial infection/exposure

Millary TB in 50%

GRADUAL ONSET:

  • personality change, irritability
  • FEVER, drowsiness, neck stiffness
  • decreased LOC
39
Q

**Tests for TB meningitis?

A

+ve TUBERCULIN test

+ve Mantoux

CSF clear and similar to viral CSF except with low glucose

Hard to diagnose under microscope as bacilli are scarce

Can also look at gastric washings

40
Q

Prognosis of TB meningitis?

A

Poor

41
Q

Treatment of TB meningitis?

A

4 drugs, RIPE for 10 months, then cute down to RI

42
Q

Organisms causing meningitis

in immunocompromised host?

A

Listeria in raw mik or soft cheese

Cryptococcus yeast

43
Q

Causes of encephalitis? (8)

A

MAINLY VIRAL

HSV 1 (most common)

Also:

  • Influenza
  • VSV
  • Enteroviruses
  • Rabies
  • Arboviruses
  • Hendra and Nipah viruses
  • Japenese B
44
Q

Non viral causes of encephalitis? (9) (recognise)

A
N. meningitidis
Listeria monocytogenes
Scup typhus
Leptospirosos
Melliodosis

Malaria
TB
Borrelia and Brucella

45
Q

Investigations and management of encephalitis

A

High dose aciclovir and abx if high suspicion

CSF
THroat and stool samples
INeural imaging, EEG

46
Q

Most common cause of encephalitis?

A

HSV 1

Causes 1-4 cases per million per year

80% of those untreated will die

47
Q

Clinical features of HSV1 encephalitis

A
Headache
Fever
Decreased LOC
Confusion
Dysphasia
48
Q

Treatment of HSV 1 encephalitis?

A

Aciclovir 14-21 days

49
Q

CNS complications of measles

A

Post infectious encephalitis (autoimmune)

Measles Inclusion body encephalitis (immunocompromised)

*** SSPE, Subacute sclerosing panencephalitis several years after exposure in children (progressive neurodegenerative condition)

50
Q

3 main types of demyelinating encephalopathies?

A

All are viral

  • Measles, SSPE, MIBE
  • Progressive multifocal encephalopthy by JC virus in AIDS
  • Rubella encephalitis
51
Q

What does the JC virus cause in the CNS of AIDS patients?

A

Progressive multifocal encephalopathy, a demyelinating disease

52
Q

Clinical features of a brain abcsess

A

Varied!

Headache, drowsiness, confusion

Seizures

N + V

Motor/sensory impairments

Papillodema and ataxia

53
Q

Causes of brain abscesses?

A

Contiguous suppurative focus 40-50% (otitis media or another infection crossing into CNS)

Haematogenous spread from distant infection 25%

Trauma 10%

54
Q

Common causes of brain abscess

A

Often polymicrobial

Staph aureus
Streptococci
Bacteriodes
Fusobacterum
Pseudomonas etc

Need to look at infection sourse

55
Q

Tx for abscess with unknown cause?

A

Cover for streptococci with penicillin or cefotaxime or ceftriaxone

56
Q

Tx for brain abscess causesd by staph aureus

A

Vancomycin

57
Q

Tx for brain abcess caused by pseudomonas aeruginoas

A

Cefepime or ceftazidime

58
Q

Tx for brain absess in HIV patient?

A

May need to consider cover for organisms like Toxoplasma

59
Q

3 examples of prion diseases

A

Sporadic CJD (dementia, ataxia, can detect 14-3-3 protein in CSF)

Familial Transmissable Spongiform Encephalopathies TSE (autosomal dominant)

Kuru

60
Q

Another name for bovine spongiform encephalopathy?

A

New variant CJD

mad cow disease, not spordaic

61
Q

Which prion disease has 14-3-3 protein in CSF?

A

New variant CJD

Also see a high T2 signal in post thalamus at MRI

Plaques on the brain

62
Q

Who gets new varieant CJD?

A

Younger patietns

60% have psychiatric symptoms initially