CNS Infections - Bacterial and Fungal Meningitis (27)

Question 1

CNS infections

Answer 1

Meningitis (bacterial, viral, TB, cryptococcus), brain abscess, encephalitis, toxin mediated

Question 2

What is meningitis?

Answer 2

Infection of CSF/meninges

Question 3

How does meningitis present?

Answer 3

Acute fever, headache, neck stiffness, +/- rash, fully conscious, usually viral

Question 4

What is encephalitis?

Answer 4

Infection of brain tissue

Question 5

How does encephalitis present?

Answer 5

Acute fever, headache, neck stiffness, altered conscious level, seizures, focal neurological signs, usually viral

Question 6

What is a brain abscess?

Answer 6

Abscess within brain tissue

Question 7

How does brain abscess present?

Answer 7

Insidious onset of fever, headache, +/- neck stiffness, +/- altered conscious level, seizures, focal neurological signs, usually bacterial (parasitic?)

Question 8

How does invasion via micro-organisms occur?

Answer 8

Blood-borne invasion (blood-brain barrier/blood CSF barrier), peripheral nerves

Question 9

What does normal CSF look like?

Answer 9

Clear

Question 10

Polymorphic nucleoles likely to be

Answer 10

Bacterial

Question 11

Neisseria meningitidis

Answer 11

Gram negative diplococci, require blood for growth, 13 capsular types (A, B, C, W135, Y most common), detected by nucleic acid amplification (PCR)

Question 12

Natural habit of N. meningitidis

Answer 12

Nasopharynx, 5-20% carriers (increased smokers), half strains non-capsulate, increase in Gp A carriage rates before epidemics

Question 13

Factors affecting intravascular survival (N. meningitidis)

Answer 13

Capsule - protects against complement-mediated bacteriolysis and phagocytosis

Acquisition of iron from transferrin

Question 14

N. meningitidis BBB

Answer 14

Cross BBB and multiply in subarachnoid space, can remain in blood stream/not cross BBB

Question 15

N. meningitidis can cause

Answer 15

Fulminant septicaemia, septicaemia with purpuric rash, septicaemia with meningitis, pyogenic/purulent meningitis with no rash, chronic meningococcal bacteraemia with arthralgia, focal sepsis, conjunctivitis, endophthalmitis

Question 16

Is rash blanching or non-blanching?

Answer 16

Can be blanching early in disease and progress to be non-blanching

Question 17

Treatment of N. meningitidis

Answer 17

Ceftriaxone, cefotaxime (Penicillin)

Question 18

Chemoprophylaxis of contacts on invasive disease (N. meningitidis)

Answer 18

Close/kissing contacts, Rifampicin/Ciprofloxacin

Question 19

Vaccination for N. meningitidis

Answer 19

Active against Group A and C and W135 (not against Group B)

Question 20

When is peak of N. meningitidis?

Answer 20

Winter

Question 21

Local outbreaks of N. meningitidis

Answer 21

Population of susceptible individuals, high transmission rate, virulent, capsulate strain

Question 22

Haemophilus influenzae

Answer 22

Unable to grow in the absence of blood/constituents of blood, small, pleomorphic gram negative cocco-bacilli/bacilli, some strains produce a polysaccharide capsule (6 antigenic types a-f, type b causes most invasive disease)

Question 23

Normal carriage of H.influenzae

Answer 23

Restricted to humans, 25-80% carry non-capsulate strains, 5-10% carry capsulate strains

Question 24

Throat carriage of H.influenzae

Answer 24

Invasion of submucosa > blood stream > (invasive infections if meningitis, infants, >2 months - 2 years)

Question 25

Virulence factors of H.influenzae

Answer 25

Type b capsule, Fimbriae, IgA proteases, outer membrane proteins/lipolysaccharide (intercurrent viral infection)

Question 26

Treatment of H.influenzae

Answer 26

Ceftriaxone, cefotaxime (ampicillin, B-lactamase producing strains common)

Question 27

Chemoprophylaxis of H.influenzae

Answer 27

Rifampicin

Question 28

Vaccines for H.influenzae

Answer 28

Type b conjugates vaccines (dramatic reduction in incidence of invasive disease)

Question 29

Streptococcus pneumoniae

Answer 29

Gram positive cocci, cells in pairs, requires blood/serum for growth, a-haemolytic activity on blood agar (green)

Question 30

What test can be done to see if Step pneumoniae is present?

Answer 30

Optochin test (ethyldydrohupreine)

Question 31

Who does Step pneumoniae effect?

Answer 31

All ages, more severe in elderly and immunocompromised

Question 32

Treatment of Step pneumoniae

Answer 32

Ceftriaxone, cefotraxime (Penicillin resistance)

Question 33

Vaccine for Step pneumoniae

Answer 33

Conjugate vaccine available against serotypes

Question 34

Steroids for meningitis in adults

Answer 34

Must be given shortly before/with first dose of antibiotics, should be given if Step pneumoniae suspected

Question 35

Neonatal meningitis usually caused by

Answer 35

Group B beta-haemolytic streptococci, E.coli, Listeria monocytogenes (rare)

Question 36

Neonatal extent of infection (variable onset)

Answer 36

Early 5 days - meningitis

Question 37

Treatment of neonatal meningitis

Answer 37

Cefotaxime (ampicillin and gentamicin)

Question 38

Acute complications of meningitis

Answer 38

Death, overwhelming sepsis, raised ICP

Question 39

Chronic complications of meningitis

Answer 39

Deafness, delayed development, seizures, stroke, hydrocephalus

Question 40

Lymphocytic meningitis

Answer 40

Viral (Enterovirus/HSV 2/polio), benign outcome

Question 41

Consequence of polio meningitis

Answer 41

Paralysis

Question 42

Bacteria causing lymphocytic meningitis

Answer 42

Spirochete - treponemal/borrelia

Question 43

Lymphocytic meningitis - TB

Answer 43

Insidious onset

Question 44

Risk factor for TB

Answer 44

Immunocompromised, alcoholic, endemic area

Question 45

Detection of TB

Answer 45

Ziehl Neelsen/Fluorescent antibody stain

Question 46

Toxoplasma gondii encephalitis

Answer 46

Protozoan, contracted by eating contaminated meat, resembles glandular fever, immunocompromised

Question 47

Cryptococcal meningitis

Answer 47

Lymphocytic meningitis, yeast, common with late HIV, insidious onset

Question 48

Where are yeast forms of Cryptococcal meningitis seen?

Answer 48

In CSF in Indian Ink stain

Question 49

Cryptococcal meningitis treatment

Answer 49

Prolonged course - amphotericin, flucytosine, fluconazole

Question 50

Encephalitis

Answer 50

Altered conscious level, HSV 1 most common, affects temporal lobes, 50% over 50s

Question 51

Diagnosis of encephalitis

Answer 51

Detecting viral nuclei acid in CSF (PCR)

Question 52

Rabies encephalitis

Answer 52

Common, dog, fox, bat bites, 100% mortality, preventable by vaccination

Question 53

Clostridium tetani

Answer 53

Gram positive spore forming bacillus, terminal round spore (drumstick), strict anaerobe

Question 54

How is Clostridium tetani spread?

Answer 54

Contaminated soil > wound (major/minor)

Question 55

Clostridium tetani's toxin

Answer 55

Non-invasive, produces tetanospasmin, toxin genes plasmid encoded, spreads via bloodstream and retrograde transport, binds to ganglioside receptors and blocks release of inhibitory interneurones convulsive contractor of voluntary muscles

Question 56

Tetanus/lock jaw

Answer 56

Tonic muscle spasms, trismus (jaw), opisthotonus (spine bent), respiratory difficulties, cardiovascular instability (sympathetic nervous system), increased muscle tone

Question 57

Most common entry site of Clostridium tetani

Answer 57

Via feet

Question 58

Clostridium tetani treatment

Answer 58

Antitoxin (horse/human), Penicillin/metronidazole, drugs for spasms, muscle relaxants, respiratory support

Question 59

Prevention of Clostridium tetani

Answer 59

Toxoid

Question 60

Epidemiology of Clostridium tetani

Answer 60

1 millon required hospital treatment each year