Nervous system infections

Question 1

which people have a higher risk of developing infectious meningoencephalitis

Answer 1

⭡risk in neonates, elderly, immunocompromised, pregnancy, crowded enviroments

Question 2

what are the mechanisms of infection that can cause a meningoencephalitis

Answer 2

hematogeneous dissemination

direct trauma

contagious spread

Question 3

pathophysiology of hematogeneous dissemination for meningoencephalitis

Answer 3

hematogeneous dissemination → specially from the nasopharynx (most commonly Neisseria)

Question 4

pathophysiology of direct trauma for meningoencephalitis

Answer 4

direct trauma → fractured skull, VP shunts, neurosurgical procedures, etc. (think about staph aureus and staph epidermidis)

Question 5

pathophysiology of contagious spread for meningoencephalitis

Answer 5

contagious spread → otitis media, sinusitis (strep pneumo)
- remember that otitis media in children is commonly caused by the non typeable H.influenza, type B is uncommon because of vaccination

Question 6

how do you distinguish meningitis and encephalitis

Answer 6

meningitis → Kerning and Brudzinski sign

encephalitis → focal neurological deficits

Question 7

typical triad of bacterial meningoencephalitis

Answer 7

rapid onset fever, nuchal rigidity, headache or altered mentation

Question 8

what’s the clinical presentation of meningoencephalitis

Answer 8

typical triad = rapid onset fever, nuchal rigidity, headache or altered mentation

hypotension, tachycardia, photophobia, emesis, altered mentation, seizures

Kerning and Brudzinski sign, papilledema, Cushing reflex

Question 9

what do you expect to find in a lumbar puncture of a bacterial meningitis

Answer 9

⭡opening presure

cloudy fluid

pleocytosis (>1,000 mm^3, granulocytosis = neutrofiles)

⭡protein, ⭣glucose

Question 10

what are the typical pathogens of a bacterial meningitis

Answer 10

S.pneumonia
N.meningitis
H. influenzae type B
Listeria

Question 11

meningococcemia is caused by which pathogen

Answer 11

Neisseria meningitis

Question 12

what’s the presentation of meningococcemia ? how does it work?

Answer 12

respiratory droplets (crowded environments) → colonizes nasopharynx → jumps to the CSF (hematogeneous dissemination)

endotoxin (LOS) → septic shock

presentation → purpura/petechiae

complication: waterhouse-friderichsen syndrome = acute adrenal insufficiency

Question 13

do you give prophylaxis for someone that was closed with someone that now has meningococcemia?

Answer 13

prophylaxis is necessary for people with close contact !!

Question 14

is there a vaccine for neisseria meningitis?

Answer 14

there is a vaccine = MenACWY

• you can still get the B serotype because we can’t vaccine against it since it’s fairly similar to humans
• even though it’s a risk people in the military get it (risk populations can get it → including people without their spleen)

Question 15

most common cause of adult meningitis

Answer 15

strep penumonia

Question 16

meningitis caused by strep penumo and neisseria are more common in people with ….

Answer 16

a prior splenectomy → no spleen = no antibodies = no opsonization

Question 17

which pathogen that causes meningitis leaves the most sequels, including future trombosis

Answer 17

strep penumonia

Question 18

which population is susceptible to an infection with listeria

Answer 18

Listeria happens in the old (elderly) and the young (neonates)

Question 19

what’s the most common atypical bacteria that causes meningitis?

Answer 19

S. aureus (direct trauma, VP shunt)

Question 20

what’s the clinical presentation of a viral meningitis

Answer 20

non specific signs/symptoms: low grade fever, malaise, myalgia, maculopapular rash +/- less severe meningeal signs

Question 21

what do you expect to find in a lumbar puncture of someone with viral meningitis

Answer 21

⭡/- opening pressure

clear fluid

pleocytosis (10-500/mm^3, lymphocytosis)

⭡/- protein

normal glucose

Question 22

what typical viruses cause viral meningitis

Answer 22

enteroviruses (MCC)
HSV
VZV
West Nile virus
St. Louis encephalitis virus
HIV

Question 23

when is meningitis caused by enteroviruses more commonly found

Answer 23

most common in summer months

Question 24

which are the most common enteroviruses that cause meningitis

Answer 24

• coxsackie virus → hand, foot, mouth disease
  
  • echovirus
  • poliovirus → myelitis
  • adenovirus → least high-yield

Question 25

which is the most important enterovirus that causes meningitis

Answer 25

coxsackie virus

Question 26

HSV normally causes -----------, their lesions are normally in the -------- --------

Answer 26

encephalitis temporal lobe

Question 27

characteristics of a HSV encephalitis

Answer 27

normally a temporal lobe encephalitis Kluver-Bucy syndrome: bilateral temporal lobe lesions → HSV-1 encephalitis damage to the amigdala = loss of the fear response, hyper-orality, hyper-sexuality, impulsive behaviour damage to hippocampus = amnesia (typically anterograde)

Question 28

West Nile virus is associated with ....

Answer 28

dead birds

Question 29

subacute sclerosing panencephalitis:

Answer 29

persistent measles infection → inflammatory demyelinating, ⭡anti-measles IgG in CSF

Question 30

what pathogenes cause the most common atypical meningoencephalitis

Answer 30

tuberculosis: mycobacterium tuberculosis, immunocompromised, insidious onset, AFB, ADA activity - most common form of chronic meningitis Lyme: Borrelia burgdoferi, late stage neuroborreliosis, CN VII palsy (bilateral), nocturnal parasthesias, mononeuritis multiplex Cryptococcal: cryptococcus neoformans, immunocompromised (CD4+ <100), India ink, Latex agglutination test, narrow-based budding yeast Rickettsial: Rickettsia spp., petechiae, tick exposure, non-classic bacterial LP results primary amebic: naegleria fowleri, warm freshwater ponds, rapid onset fulminant disease, hemorrhagic (RBC in LP), fatal - contiguous spread

Question 31

what do you expect to see in a lumbar puncture of a patient with atypical meningitis

Answer 31

⭡opening pressure pleocytosis (lymphocytes) ⭡protein ⭣glucose

Question 32

characteristics of a patient with neonatal meningitis

Answer 32

- 0-3 months old - lethargy, emesis, hypotonia, fever (or hypothermia), bulging fontanelle, high pitch crying, seizures

Question 33

which pathogens typically cause neonatal meningitis

Answer 33

streptococcus agalactiae (group B) - main one E.coli Listeria enteroviruses (coxsackie virus)

Question 34

how does a baby get infected with strep. agalactiae

Answer 34

streptococcus agalactiae (group B) → vaginal colonization → can ascend to the uterus → chorioamnionitis → fetus swallows it and gets into the lungs mom has to be tested 25-27 GWs = vaginal swap → if positive give Gentamicin + Ampicillin

Question 35

what do you expect to see in a MacConkey agar depending on the pathogen that causes neonatal meningitis

Answer 35

if you test a sample in MacConkey agar and: - it doesn’t grow anything = gram (+) = strep, listeria - if it grow something = gram (-) = e.coli (pink color)

Question 36

which findings in a patient suggest an elevated ICP?

Answer 36

papilledema altered mentation hipotension irregular respirations focal neurological deficits

Question 37

do you always do a lumbar puncture if you suspect the patient has an encefalitis?

Answer 37

only if the px doesn't have any sings of an elevated ICP

Question 38

what's the pharmacological management for adult meningitis

Answer 38

- empiric: ceftriaxone + vancomycin + dexamethasone +/- ampicillin - fungal: amphotericin B - tuberculous: RIPE variants (ethambutol has poor CNS penetration) - cryptococcal: amphotericin B + flucytosine - lyme: ceftriaxone - HSV: acyclovir

Question 39

what's the pharmacological management for neonatal meningitis

Answer 39

empiric = cefotaxime + ampicillin + gentamicin

Question 40

general principles of infectious cerebral lesions

Answer 40

focal neurological deficits (eg. hemiparesis, aphasia), ⭡risk of seizures avoid LP if suspect mass lesions of ⭡ ICP → risk of brain herniation

Question 41

typical abscess pathogens

Answer 41

commonly polymicrobial (oral anaerobes → bacteroides) - dental infections Viridans streptococci (MCC) → subacute endocarditis - mitral valve→ septic emboli staph aureus staph epidermidis → VP shunts, neurosurgical equipment

Question 42

Atypical abscess/cyst-forming pathogens

Answer 42

nocardia → immunocompromised patient, partial acid fast, initial pulmonary disease - inhaled cryptococcus neoformans → pigeons/bird droppings, immunicompromised (CD4+ <100), india ink, latex agglutination test → “soap bubble” lesions (pseudocystitis) toxoplasma gondii → cat feces, immunocompromised (CD4+ <100), multiple “ring-enchancing” lesions, microscopy with tachyzoites - oral infection taenia solium → consumption of raw pork, eosinophilia, cystic lesion(s) +/- invaginated scolex

Question 43

Neurotoxic pathogens

Answer 43

JC virus → reactivation → PML, immunocompromised (CD4+ <200), asymethric T2-hyperintense lesions primary CNS lymphoma → viral associations (EBV), immunocompromised (CD4+ <100), solitary variable (homogenous vs ring) enhancing lesions on CT with contrast HIV encephalotogy → diffuse atrophy, immunocompromised, symmetric T2-hyperintense lesions spongiform encephalopathy → misfolded proteins (PRPsc), startling myoclonus, rapidly progressing dementia, ⭡14-3-3 protein (CSF), triphasic periodic sharp waves (EEG) - Creutzfeldt-Jakob disease (CJD)