CNS Infections

Question 1

Define: Meningitis

Answer 1

inflammation of the meninges and cerebral spinal fluid caused by the invasion of a pathogen into the subarachnoid space

Question 2

Define: Encephalitis

Answer 2

inflammation of the brain tissue itself with clinical evidence of neurologic dysfunction

Question 3

Define: Brain abscess

Answer 3

focal infection of the brain with develops into a collection of pus surrounded by well-vascularized capsule

Question 4

Define: Shunt infections

Answer 4

infections of surgically implanted CNS shunts

Question 5

What are the pathways for CNS infection?

Answer 5

1. hematogenous spread= pathogen colonize nasopharyngeal mucosa, then enter the bloodstream, and invade the CSF in subarachnoid space
2. contiguous spread= direct pathway into meninges from nearby infected area (sinusitis, otitis, mastoiditis)
3. direct inoculation= trauma, surgery

Question 6

What are the risk factors for CNS infections?

Answer 6

• upper respiratory tract infections, otitis media, mastoiditis
• splenectomy or functional asplenia
• immunocompromised patients
• head trauma, recent neurosurgery
• intrathecal medication pump
• close contact with others with meningitis
• newborn infants
• recent travel

Question 7

What are the signs/symptoms of a CNS infection?

Answer 7

1. fever
2. nuchal rigidity (neck stiffness with up and down movement)
3. altered mental status

chills, vomiting, photophobia, severe headache

Question 8

What is the empiric therapy for CNS infection in an infant <1 month?

Answer 8

• ampicilin + cefotaxime
  OR
• ampicillin + aminoglycoside

Question 9

What is the empiric therapy for CNS infection in patients 1-23 months?

Answer 9

vancomycin + 3rd generation cephalosporin (cefotaxime or ceftriaxone)

Question 10

What is the empiric therapy for CNS infection in patients 2-50 years old?

Answer 10

vancomycin + 3rd generation cephalosporin (cefotaxime or ceftriaxone)

Question 11

What is the empiric therapy for CNS infection in patients > 50 years old?

Answer 11

vancomycin + ampilillin + 3rd generation cephalosporin (cefotaxime or ceftriaxone)

Question 12

What is empiric therapy for CNS infection with head trauma?

Answer 12

vancomycin + anti-pseudomonal beta-lactam (cefepime or meropenem or ceftazidime)

Question 13

What is empiric therapy for CNS infection post neurosurgery?

Answer 13

vancomycin + anti-pseudomonal beta-lactam (cefepime or meropenem or ceftazidime)

Question 14

What is empiric therapy for CNS infection with CSF shunt?

Answer 14

vancomycin + anti-pseudomonal beta-lactam (cefepime or meropenem or ceftazidime)

Question 15

Which antipseudomomal beta-lactams may be used for empiric treatment for CNS infections with predisposing factors?

such as: head trauma, post neurosurgery, CSF shunt

Answer 15

• cefepime
• meropenem
• ceftazidime

Question 16

What is the treatment duration of streptococcus pneumoniae?

Answer 16

10-14 days

Question 17

What is the duration of therapy for neisseria meningitis?

Answer 17

7 days

Question 18

What is the duration of therapy for haemophilus influenzae?

Answer 18

7 days

Question 19

What is the duration of therapy for listeria monocytogenes?

Answer 19

3-6 weeks

Question 20

What is the preferred treatment for strep. pneumoniae infection with MIC <0.1 mcg/mL?

Answer 20

• penicillin G
• ampicillin