CNS Infections

Question 1

What is meningitis?

Answer 1

Infection of CSF

Question 2

What are the clinical features of meningitis?

Answer 2

• Usually viral but can be bacterial

ACUTE fever, headache, neckstiffness, +/- rash, conscious (no focal neurological signs)

Question 3

What is encephalitis?

Answer 3

Infection of brain tissue

Question 4

What are the clinical features of encephalitis?

Answer 4

• Usually viral
  ACUTE fever, headache, neck stiffness
• altered conscious level, focal neurological signs, seizures

Question 5

What is a brain access?

Answer 5

Access in the brain (usually bacterial but can be parasitic)

Question 6

What are the clinical features of a brain access?

Answer 6

+/- altered consciousness, focal neurological signs, insidious (gradual) fever, neck stiffness, headache

Question 7

What routes can microorganisms invasion occur via?

Answer 7

• Direct spread from adjacent focus e.g. paranasal sinus, middle ear
• Blood borne spread e.g. septicaemia, septic emboli (endocarditis)
• Iatrogenic spread e.g. via lumbar puncture

Question 8

What is pachymeningitis?

Answer 8

Spread of infection from skull

Question 9

What is leptomeningitis?

Answer 9

Spread of infection from blood

Question 10

What are the characteristics of CSF with bacterial infection?

Answer 10

• Increased cells in CSF (polymorphs)
• Reduced/absent glucose
• Increased protein
• Opaque/turbid appearance

Question 11

What are the characteristics of CSF with fungal infection (e.g. cryptococcus)?

Answer 11

Increased number of cells (lymphocytes)

• Normal or reduced glucose
• Increased protein

Question 12

What are the most important organisms in bacterial meningitis?

Answer 12

Neonates: E. Coli, listeria monocytogenes, Group B Strep (e.g. agalactiae), H influenzae

2-18yrs: Neisseria meningitides

Over 30yrs/immunocompromised: Strep Pneumoniae

Question 13

What are the clinical complications of bacterial meningitis?

Answer 13

• Cerebral infarction
• Obstructive hydrocephalus
• Cerebral abscess
• Epilepsy
• Long term problems e.g. deafness, seizures,, delayed development

Question 14

What are the CSF characteristics of TB meningitis infection?

Answer 14

Increased Lymphocyte cells
Reduced glucose
Increased proteins
Subacute meningitis (mild inflammation)

Question 15

What are the clinical features of TB meningitis? What is the treatment?

Answer 15

Thick gelatinous exudate
Non specific symptoms
Anti-TB chemotherapy

Question 16

What are the main fungal infections that cause meningitis? What type of patients are suavely affected?

Answer 16

Immunocompromised patients

• Cryptococcus neoformins
• Candida albicans
• Aspergillus fumigatus