CNS Infections

Question 1

types of aseptic meningitis (neg bacterial cultures)

Answer 1

viral meningitis, fungal infections, bacterial infections

Question 2

clinical signs and symptoms - meningitis

Answer 2

petechiae rash first 3 days; purpuric lesions; severe headache, fever, pos Brudzinski’s sign (cervical rigidity), hamstring spasm, pos blood culture may be seen

Question 3

describe Brudzinski’s sign and Kernig’s sign

Answer 3

Brudzinski’s: cervical rigidity causing knees to pop up; Kernig’s sign: unable to straighten leg in 90 degree angle without pain

Question 4

signs and symptoms of bacteremia

Answer 4

upper RTI, pos blood culture but not much replication, transient with fever, resolves in 1-2 days

Question 5

signs and symptoms of meningococcemia

Answer 5

pos blood culture, replication in the blood, malaise, rash, may resolve or proceed

Question 6

*signs and symptoms of meningitis

Answer 6

sudden onset fever, nausea, vomiting, headache, decreased ability to concentrate, myalgias; may have disseminated intravascular coagulation, shock; will have pos Brudzinski’s and Kernig’s signs

Question 7

what causes disseminated intravascular coagulation?

Answer 7

activation of extrinsic and intrinsic clotting cascade by macrophage production of procoagulant tissue factor

Question 8

what are the symptoms and signs of DIC?

Answer 8

widespread ischemic changes and bleeding due to using up of clotting factors; septic shock; increased vascular permeability, fluid loss

Question 9

what is Waterhouse-Friderichsen syndrome?

Answer 9

adrenal infarction leading to acute adrenal insufficiency (associated with DIC, not meningitis)

Question 10

highest incidence of meningitis in this age group

Answer 10

children 6-12 months

Question 11

morphology of Neisseria meningitidis

Answer 11

gram-neg, diplococcic, lipooligosaccharide to form effective capsule, has serogroups

Question 12

metabolism of Neisseria meningitidis

Answer 12

aerobic but can grow anaerobic, cyt c oxidase positive, ideally grown in increased CO2, grows on blood agar, choc agar

Question 13

Neisseria meningitides pathogenesis- function of capsule, pili, and LOS

Answer 13

capsule resistance to phagocytosis, pili for adherence, LOS production of cytokines esp. TNF (may result in septic shock)

Question 14

major cause of N. meningitides pathology

Answer 14

LOS (TNF, inflammation)- activates macrophages through the Toll pathway, which leads to production of procoagulant TF, subsequent bleeding

Question 15

physical findings on path slides for N. meningitidis

Answer 15

PMN’s, gram neg diplococcic on gram stain of CSF

Question 16

diagnosis procedures for N. meningitidis

Answer 16

culture of CSF on blood and choc agars (gold standard), blood cultures when meningococcemia suspected.

Question 17

treatment of suspected meningitis needs to cover..// what ABs should be used?

Answer 17

meningococcus, pneumococcus, hemophilus (cefotaxime, vancomycin); rif and ciprofloxacin for contacts

Question 18

methods of immunity to meningitis

Answer 18

antibodies directed against the CAPSULE, vaccines available

Question 19

life cycle of toxoplasma gondii

Answer 19

oocyst in cat feces, ingested, sporozoites hatch into tachyzoites in the gut of the animal, goes through asexual repro, infects primarily macrophages (liver, lungs)

Question 20

the definitive host (cat) houses which stages of the organism?

Answer 20

sexual and asexual stages (psuedocysts form containing bradyzoites)

Question 21

toxo is asymptomatic in what percentage of cases?

Answer 21

80-90%

Question 22

picture of toxo resembles..

Answer 22

infectious mono or CMV infection

Question 23

how severe toxo manigefests

Answer 23

CNS disease: encephalopathy, meningoencephalitis

Question 24

describe infection of congenital toxo

Answer 24

newly acquired in mother during pregnancy; systemic spread to the fetus

Question 25

what is the outcome of toxo infection during 1st trimester?

Answer 25

spontaneous abortion, stillbirth, severe disease

Question 26

what is the outcome/signs of toxo infection in 2nd/3rd trimester?

Answer 26

chorioretinitis (25% of cases), epilepsy, encephalitis, hydrocephaly, retardation

Question 27

diagnosis of toxo

Answer 27

serology: determination of 4-fold increase in titer essential to diagnosis of acute infection (1/3 of pop. is seropositive); brain imaging

Question 28

treatment for HIV-associated toxo

Answer 28

sulfadiazine and pyrimethamine; maintain to prevent recurrence

Question 29

bugs that cause primary amoebic meningoencephalitis

Answer 29

Naegleria fowleri, Acanthamoeba sp.

Question 30

where Naegleria fowleri is found

Answer 30

amoeba-flagellate in soil, water; found in 50% of fresh (WARM) water

Question 31

how is Naegleria fowleri acquired by humans?

Answer 31

getting water in nose; amoeba penetrates the cribriform plate

Question 32

signs of meningoencephalitis caused by Naegleria fowleri

Answer 32

headache, stiff neck, fever, lethargy, rapid progression to confusion, convulsions, coma

Question 33

naegleria fowleri infection is fatal in how much time?

Answer 33

6-`7 days (mean=10)

Question 34

blood work picture for diagnosis of meningitis

Answer 34

high protein, low glucose, a few WBC’s; gram stain is NEGATIVE (why?)

Question 35

describe the detection methods of amoeba in purulent CSF

Answer 35

wet mount; gram stain is difficult to recognize, use Wright stain because its distinctive

Question 36

treatment of meningitis caused by naegleria fowleri

Answer 36

all: amphotericin (IV and intrathecally), fluconazole, azithromycin, rifampin, miltefosine, dexamethasone

Question 37

Acanthamoeba is acquired by

Answer 37

water in nose, penetration of cribriform plate

Question 38

infections associated with Acanthamoeba

Answer 38

CNS infection (longer, chronic granulomatoud encephalitis); ocular infection (bruised eye contaminated with dirt, contaminated contacts, results in keratitis)