CNS Infections

Question 1

What are the most common causative agents of viral meningitis?

Answer 1

Enterovirus

HSV

Question 2

What are the most common causative agents of bacterial meningitis?

Answer 2

Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae type b

Question 3

4 symptoms of meningitis

Answer 3

Severe headache
Neck stiffness
N+V
Lethargy

Question 4

5 signs of meningitis

Answer 4

Photophobia
Non-blanching rash

Fever
Kernig’s Sign: hips flexed, pain/ resistance on passive knee extension
Brudzinski’s Sign: flexion of the hips when neck is flexed

Question 5

4 risk factors for meningitis

Answer 5

Young/ Elderly
Immune suppression.
Crowding (college students) .
Close contact

Question 6

What would a lumbar puncture of bacterial meningitis show?

Answer 6

Cloudy CSF
High neutrophils
High protein
Low glucose

Question 7

What would a lumbar puncture of viral meningitis show?

Answer 7

High lymphocytes
High protein
Normal glucose

Question 8

What would a lumbar puncture of TB meningitis show?

Answer 8

Fibrinous CSF
High lymphocytes
High protein
Low glucose

Question 9

Ix for meningitis

Answer 9

Bloods: culture, inflammatory markers, CBC, metabolites
CSF: cell count, protein, glucose, gram stain

Question 10

Initial tx for suspected bacterial meningitis presenting in hospital

Answer 10

Support- O2, fluids, airway
Dexamethasone IV
Ceftriaxone IV

Question 11

Initial tx for suspected bacterial meningitis presenting in community

Answer 11

Emergency transfer

Benzylpenicillin sodium IM/ IV

Question 12

Tx for confirmed bacterial meningitis

Answer 12

Targeted abx
Analgesia
Antipyretics
Nutritional support
Hydration
Metabolic monitoring

Question 13

Tx for viral meningitis

Answer 13

Supportive:
Analgesia
Antipyretics
Nutritional support
Hydration.

Question 14

Most common cause of encephalitis in the UK

Answer 14

HSV 1

Question 15

What is encephalitis?

Answer 15

Inflammation of brain parenchyma associated with neurological dysfunction

Question 16

What is meningoencephalitis?

Answer 16

Inflammatory process, often due to viral infection, involving both brain + meninges

Question 17

5 features of presentation of encephalitis

Answer 17

Altered mental status
Fever
Altered consciousness
Seizures
Headache

Question 18

4 common neurological defects in encephalitis

Answer 18

Personality changes
CN palsies
Speech problems
Motor + sensory deficits

Question 19

Ix for encephalitis

Answer 19

Bloods: leukocytosis

LP + CSF analysis: cell count, protein, glucose, PCR, serology

Question 20

Tx for encephalitis with suspected viral aetiology

Answer 20

Acyclovir IV

Question 21

Pathogenesis of meningoencephilitis

Answer 21

Infection starts in meninges then spreads to brain parenchyma

Question 22

Aetiology of brain abscesses

Answer 22

Infection with bacterial, fungal, or parasitic organisms
Direct spread of sinus, ear or dental infection/ inoculation following open skull fracture or haematogenous spread from infective foci
Single or multi-focal

Question 23

Most common pathogens causing brain abscesses

Answer 23

Streptococci viridans (often 2 to sinusitis)
Staph aureus
Coagulase -ve staph

Question 24

Pathogenesis of brain abscesses

Answer 24

Early cerebritis: infiltration of neutrophils + oedema
Late cerebritis: Necrosis, liquefaction + macrophage infiltration
Formation of fibrotic capsule around the lesion

Question 25

5 Sx of brain abscess

Answer 25

Dull persistent headache
Focal neurological deficits- CN 3/6 palsy
Sx of raised ICP: N+V, AMS
Fever
Seizures

Question 26

Ix for brain abscess

Answer 26

Raised CRP + ESR
Leukocytosis
CT: faster - >,1 ring enhancing lesion
MRI: detailed - >,1 ring enhancing lesion
Biopsy
Needle aspiration/ surgical drainage

Question 27

Tx for suspected brain abscess

Answer 27

Vancomycin IV
Metronidazole/ Clindamycin IV
Ceftriaxone IV
Anticonvulsant: Phenytoin/ Carbamezapine/ Sodium valproate PO
Dexamethasone IV (reduces ICP)

Question 28

Tx for confirmed brain abscess

Answer 28

Surgical drainage + biopsy