CNS infections

Question 1

Name the different routes of CNS infection?

Answer 1

1. blood-borne
2. parameningeal supparation (otitis media)
3. defect in dura (direct spread)

Question 2

Which are the main organisms causing meningitis and which age group do they affect most?

Answer 2

1. N. meningitidis (meningococcus) : children/young adults
2. S. pneumoniae (pneumococcus): elderly/children <2/immunocompromised (e.g. splenectomy)
3. Hib - rare - young under 5
4. E.coli/listeria/group b strep: babies

Question 3

What are the signs of meningitis in children?

Answer 3

Flaccid
Lack of feeding
bulging fontanelle
febrile fit

Question 4

What are the two signs of meningeal irritation of the motor roots?

Answer 4

Kernig’s sign (spasm when bending leg)

Brudzinski’s sign (flexion of neck, flexion of hips and knees)

Question 5

What is menigococcal disease?

Answer 5

Meningitis + septicaemia

Question 6

What are some of the risk factors for poorer outcome with meningitis?

Answer 6

Older age
Otitis media
Lower GCS
Absence of rash

Question 7

How would you diagnose meningitis?

Answer 7

Lumber puncture - CSF sample

increased WCC, low glucose level

Question 8

What is important for antibiotics treating meningitis?

Answer 8

bactericidal!

shorter treatment course

Question 9

Treatment strategy for meningitis?

Answer 9

1. Antibiotics
2. Anti-convulsants
3. Adequate oxygenation
4. Prevention of hypoglycaemia
5. reduce ICP

Question 10

Name the different antibiotics used to treat meningitis?

Answer 10

Benzylpenicillin
Ceftriaxone/Cefotaxime
Chloramphenicol

Question 11

Which antibiotic forms the first line treatment for meningitis?

Answer 11

Ceftriaxome - longer half life, dose less often

Cefotaxime

Question 12

Advantages and diasdvantages of chloramphenicol?

When is likely to be used?

Answer 12

Advantage: best penetration into the CNS
Disadvantage: bacteriostatic, resistance has emerged amongst Hib, pneumococci

likely to be used when patient is allergic to other treatment options

Question 13

Empirical treatment for meningitis of unknown cause?

Answer 13

Ceftriaxone/Cefotaxime

+ amoxicillin: if over 60 or immunocompromised

Question 14

Most common organism cause of brain abscess?

Answer 14

streptococcus milleri

Question 15

Treatment for brain abscess?

Answer 15

(dental or sinus source) Ceftriaxome + Metronidazole

Question 16

Which antibiotics are recommended to treat meningitis caused by n. meningitidis?

Answer 16

Benzylpenicillin

C or C

Question 17

If a patient presents with meningitis but is allergic to penicillin, what are the treatment options?

Answer 17

Dependent on the severity of the allergy, some patients with a penicillin allergy will also react to cephalosporins - in which cases, we can no longer use Ceftriaxone or Cefotaxime

but: Chloramphenicol is then an option

Question 18

What would you expect to see from a CSF sample of a patient with bacterial vs viral meningitis?

Answer 18

Bacterial:
low glucose
WCC: high neutrophil
increased protein

Viral:
normal glucose
WCC: high lymphocyte
increased/normal protein

Question 19

What is the usual duration of antibiotic treatment for meningococcus vs pneumococcus?

Answer 19

meningococcus: 7 days
pneumococcus: 14 days

Question 20

What is the advantage of using Ceftriaxone?

Answer 20

longer half-life

shorter dosing