26 - Bacterial and fungal meningitis

Question 1

Brain abscess - clinical presentation

Answer 1

Insidious onset of fever, headache, +/- neck stiffness
+/- altered consciousness level, seizures, focal neurological signs
Usually bacterial may be parasitic

Question 2

Neisseria Meningitidis - treatment

Answer 2

Ceftriaxone, cefotaxime
Penicillin
Early treatment w/ intensive care

Question 3

Neisseria Meningitidis - chemoprophylaxis

Answer 3

Close or kissing contacts

Question 4

Neisseria Meningitidis - vaccination

Answer 4

Active against group A and C and W135

None against group B

Question 5

Haemophilus influenzae - what is it?

Answer 5

‘Blood loving’ - unable to grow in absence of blood or certain constituents of blood.
Thought to cause influenza
Small pleomorphic gram –ve cocco-bacilli or bacilli

Question 6

Haemophilus influenzae - most invasive type

Answer 6

B

Question 7

Haemophilus influenzae - normal carriage

Answer 7

Restricted to humans
25-80% carry non-capsulate strains
5-10% carry capsulate strains
Throat carriage - invasion of submucosa to get to blood stream

Question 8

Haemophilus influenzae - invasive infections

Answer 8

Meningitis
Infections
>2months -> 2 years

Question 9

Haemophilus influenzae - virulence factors

Answer 9

Type B capsule

Fimbriae. IgA proteases, outer membrane proteins/lipopolysaccharide

Question 10

Haemophilus influenzae - Treatment

Answer 10

Ceftriaxone, cefotaxime
Ampicillin
B-lactamase producing strains common

Chemoprophylaxis of contacts of invasive disease - rifampicin

Question 11

Streptococcus pneumoniae - what is it?

Answer 11

Gram +ve cocci
Cells in pairs
Requires blood or serum for growth
a-haemolytic activity on blood agar (green)
Polysaccharide capsule

Question 12

Streptococcus pneumoniae - where does it chill?

Answer 12

Human resp tract

Transmission via droplet

Question 13

Streptococcus pneumoniae - what test for it?

Answer 13

Optochin test

Question 14

Streptococcus pneumoniae - what ages?

Answer 14

All ages
More common and severe in elderly
In immunocompromised

Question 15

Streptococcus pneumoniae - treatment

Answer 15

Ceftriaxone
Cefotaxime
No chemoprophylaxis of contacts of invasive disease

Question 16

Streptococcus pneumoniae - steroids for meningitis in adults

Answer 16

50% reduction in mortality if using dexamethasone.
Given shortly or with first dose of antibiotics
Dexamethasone decreases vanco levels in the CSF, if vancomycin used, add rifampin
Steroid treatment has no benefit in meningococcal meningitis

Question 17

Neonatal meningitis - what is the bacterium?

Answer 17

Group B beta-haemolytic Streptococci
Escheria coli
Listeria monocytogenes

Question 18

Neonatal meningitis - neonatal presentation

Answer 18

Neonatal infection w/ variable onset
Early (5 days)
Cefotaxime
Ampicillin and gentamicin

Question 19

Meningitis - complications

Answer 19

Death
Overwhelming sepsis
Raised intracranial pressure
Longer term problems inc. deafness, delayed development, seizure, stroke, hydrocephalus

Question 20

Lymphocytic meningitis - viral meningitis

Answer 20

Most common meningitis w/ enteroviruses, herpes simplex
Benign outcome
Symptomatic treatment

Question 21

Lymphocytic meningitis - spirochete

Answer 21

Treponemal

Borrelia

Question 22

Lymphocytic meningitis - TB meningitis

Answer 22

Important differential
Insidious onset
Epidemiological risk factor for TB - needs checking

Question 23

Lymphocytic meningitis - TB meningitis diagnosis

Answer 23

Difficult
AFB (acid-fast bacillus testing) often not seen on microscopy
Delay = worse prognosis

Question 24

Lymphocytic meningitis - TB meningitis - treatment

Answer 24

12 months standard TB treatment

Steroids beneficial

Question 25

Brain abscesses - features

Answer 25

Usually bacterial
Spread of organisms from adjacent structures e.g. middle ear, blood stream
Brain imaging needed

Question 26

Cryptococcal meningitis - features

Answer 26

Cryptococcus is a yeast
Common problem in patients with late stage HIV
Insidious onset
Lymphocytic meningitis
Yeast forms seen in CSF in Indian Ink stain
Prolonged course of treatment - amphotericin, flucytosine or fluconazole

Question 27

Encephalitis - features

Answer 27

Usually viral
Involvement of brain tissue
Altered conscious level
In UK, herpes simplex is most common
Tends to affect temporal lobes
Occurs at all ages, 50% in over 50s

Question 28

Encephalitis - diagnosis

Answer 28

Viral nucleic acid in CSF (PCR) may cause severe long term neurological problems

Question 29

Encephalitis - most common virus for it

Answer 29

Japanese encephalitis virus
An arbovirus
Mainly children
1/3 die of acute illness
1/3 severe long term neurological disability
1/3 recover

Question 30

Encephalitis - rabies

Answer 30

Common still in many countries
Dog, fox, bat bites
100% mortality
Preventable by vaccination

Question 31

Clostridium tetani - what type of bacterium?

Answer 31

Gram +ve spore forming bacillus
Terminal round spore (drumstick)
Strict anaerobe

Question 32

Clostridium tetani - spread

Answer 32

Soil into a wound either major or minor

Question 33

Clostridium tetani - name of toxin and what it does

Answer 33

Tetanospasmin
Toxin genes plasmid encoded
Toxin spreads via bloodstream and retrograde transport
Binds to ganglioside receptors and blocks release of inhibitory interneurones
Convulsive contraction of voluntary muscles

Question 34

Clostridium tetani - causes tetanus (clinical presentation)

Answer 34

Lockjaw
Tonic muscle spasms
Trismus
Opisthotonus
Resp. difficulties
CV instability

Question 35

Clostridium tetani - treatment

Answer 35

Antitoxin
Penicillin or metronidazole
Drugs for spasms
Muscle relaxants
Resp. support
Prevention: toxoids