CNS infections

Question 1

Time course = diffuse and acute

Answer 1

meningitis (bacterial) or toxic/metabolic cause

Question 2

Time course = focal and subacute

Answer 2

brain abscess, spinal abscess, venous vascular, trauma

Question 3

Time course = diffuse and subacute

Answer 3

meningitis (bacterial or viral), encephalitis, AI, T/M

Question 4

Time course = focal and chronic

Answer 4

brain abscess or tumor

Question 5

Three major locations of the BBB:

Answer 5

1) arachnoid epithelium
2) meninges surface
3) choroid plexus

Question 6

The medications which can cross the BBB ONLY in the presence of inflammation include:

Answer 6

penicillins
3/4th gen cephalosporins
vanco

Question 7

Pathogens that cause CNS infections:

Answer 7

1) encapsulated organisms (N. meningitidis, S. pneumoniae, H. influenzae, C. neoformans)
2) intracellular organisms (L.monocytogenes, enterovirus or arbovirus)
3) if trauma = normal flora of site
4) some organisms if systemic (S. aureus, GBS, TB, HIV)

Question 8

(3) DO NOT MISS findings on PE

Answer 8

1) meningeal irritation
2) intracranial HTN signs
3) focal neurologic sign

Question 9

The single most important diagnostic test for Meningitis_____?

Answer 9

the lumbar puncture, but not if contraindications!

Question 10

(4) Contraindications for LP:

Answer 10

1) intracranial mass lesion
2) intracranial HTN
3) severe thrombocytopenia or coagulopathy
4) agitated pt.

Question 11

(T/F) Attempts to safely perform LP should NEVER delay the administration of Abx for possible bacterial meningitis.

Answer 11

TRUE!!!

-start empiric treatment and don’t forget the blood culture!

Question 12

classic triad of sxs for meningitis

Answer 12

fever, nuchal rigidity, altered mental status (most have 2/3)

-also HA and vomiting

Question 13

Ways in which neonatal meningitis is different from non-neonatal?

Answer 13

• clinically indistinguishable from other sepsis syndromes

- must be considered in any febrile illness of a newborn

Question 14

CSF findings in bacterial meningitis

Answer 14

WBC: 1000-5000
primary cell: PMN
Glucose:

Question 15

How do I treat meningitis?

Answer 15

most often: vanco + 3rd gen cephalosporin

+ adjunctive steroid therapy to suppress inflammation (S. pneumoniae, H. influenzae, TB)

Question 16

(T/F) The most common etiology of encephalitis is bacteria?

Answer 16

False! >80% is idiopathic, otherwise is viral (HSV, VZV)

Question 17

HSV Encephalitis

Answer 17

treatable!

• involves the temporal lobe
• sxs: fever and personality change, also: seizure, aphagia, motor deficit

Question 18

Gold standard for HSV encephalitis diagnosis =

Answer 18

HSV PCR on CSF

-CSF will also often show elevated RBCs, but may also be normal

Question 19

How do I treat HSV encephalitis?

Answer 19

Acyclovir at a high dose!

• should be started immediately if suspected, do not wait for results.
• consider HSV in all pts w/ encephalitis

Question 20

(3) pathogenesis of the signs and sxs of meningitis:

Answer 20

1) inflammation (of meninges and surrounding tissue)
2) increase intracranial pressue
3) direct injury to nerve tissues