Infections in the CNS

Question 1

Primary CNS infection

Answer 1

Meningococcal meningitis

Question 2

Systemic infection with secondary CNS infection

Answer 2

Endocarditis and brain abscess, sequestered parasites in cerebral malaria

Question 3

Systemic infection with secondary CNS complications

Answer 3

(non infectious) acute confusional state with sepsis, CAP, meningism in urosepsis

Question 4

Presentation of CNS infection

Answer 4

CNS symptoms

systemic features of illness

Question 5

Investigations of CNS infection

Answer 5

Lumbar puncture, blood cultures, Imaging (CT and MRI)

EEG (viral causes)

Question 6

Bacterial infections of the CNS

Answer 6

Meningitis (encephalitis) 
-community acquired 
(acute - bacterial meningicocus, subacute - TB) 
- Healthcare associated 
(post neurosurgery, shunt related) 

brain abscess

Other

• Neurosyphillis
• Neuroborreliosis

Question 7

Viral causes

Answer 7

Encephalitis meningitis (HSV, HIV, Mumps, enterovirus, CMV) 1

Question 8

Fungal

Answer 8

Meningo-encepahlitis Mass lesion (cryptococcosis )

Question 9

Protozoal

Answer 9

Toxoplasmosis

Question 10

Signs and symptoms

Answer 10

headache
neck stiffness
fever

Question 11

Aetiology

Answer 11

Pneumococcal

• 70% underlying disorder
• middle ear disease
• head injury
• neurosurgery

Listeria

• immunosuppresion
• pregnancy

Question 12

Pneumoccoal meningitis Presentation

Answer 12

Focal signs
24% seizures
VII nerve palsy

Question 13

Mengococal disease

Answer 13

Can cause meningitis and bacteraemia only

Question 14

CT before LP

Answer 14

• not as a rule

- yes if risk factor (Age >60, CNS signs , Seizures) Blood cultures + antibiotic + therapy before CT scan

Question 15

Interpreting CSF

Answer 15

All have raised protein
Reduced glucose in Bacterial, TN and fungal infection
Normal glucose in Viral infection
Lymphocytes are seen in TB, Viral, bacterial and fungal

Question 16

Empirical antibiotic therapy for bacterial meningitis

Answer 16

Age 50 yrs of immunocompromised

• 3rd generation cephalosporin
• • ampicillin/amoxicillin

Question 17

Length of antibiotic therapy

Answer 17

relapse with listeria and pneumococcal infection if under Rx

• 14 days pneumococcal (increase if infection related complications)
• 21/7 listeriosis (ampicillin +/- gentamicin +/- Cotrimoxazole, rifampicin

Question 18

Timing of in-hospital antibiotic therapy in adults with bacterial meningitis

Answer 18

Do not delay IV antibiotics 
menigococcal disease 
-2 doses oily CMP 48hrs (in meningitis belt) 
-multiple studies of varying duration 
-usually 5-7 days