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Flashcards in LRT infections Deck (95)
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1
Q

primary agent of viral croup (laryngotracheobronchitis)

A

hPIV (hum. parainfluenza v)

pk: 2-6yo

2
Q

PIV

A

paramyxovirus, types: 1–>4, no grp. sp. Ag

Hamagglutinin and neuraminidase activity

3
Q

causes of peds bronchitis and pneumonia

A
  1. RSV 2. PIV 3. Adenovirus 4. hMPV
4
Q

agents of viral croup

A

PIV, influenza A/B, RSV, hMPB, Ad, non-polio enteroviruses, measles

5
Q

viral croup is the most common cause of what in 6mo to 6 yo children

A

RT obstruction

6
Q

croup presents with this..

in contrast to acute epiglottitis

A

SUBglottal edema vs. AE: SUPRAglottal edema

7
Q

in croup..symptoms first manifest here, then migrate here

A

in URT 1st then larynx, trachea, bronchi

8
Q

croup clin. manifest: Laryngotracheitis

A

rhinitis first, then sudden onset sore throat, hoarse/bark, stridor, SOB
steeple sign (not pathog.)
apprehension, rhonchi, crep, wheeze, dim. BS
*symps vary in intens. last 3-4d if mild

9
Q

other croup clin. manifest:

A

bronchiolitis-bronchopneumonia

10
Q

major complications of croup

A
  1. Secondary bac laryngotracheitis:
    as recov. from viral croup; px w. high fever, toxicity, RD
  2. OM
11
Q

viral croup dx

A

DFA/EIA, viral Cx, direct exam/endoscopy (be careful), NXR (“steeple sign”) to ddx from virus-like, bac., AE, airway obstr, asthma

12
Q

viral croup tx

A

supportive
oral/IM dexamethasone (better than neb. budesonide) or racemic epinephrine (bronchodilate)
NO VACCINE for viral croup

13
Q

this is the most common infection of LRT in infants & leading cause of hosp. in childhood…
and the #1 agent is..

A

bronchiolitis

RSV

14
Q

is chronic bronchitis an infectious disease?

A

no (inflamm), but low #s may be present

def: dyspnea, airflow limit, sputum production, chronic prod. cough (3mo/year for 2 yrs)

15
Q

is COPD an infectious disease?

A

no (inflamm), but low #s may be present

reduction in FEV1:FVC

16
Q

AE-CB or AE-COPD

A

acute exacerbation; frequently causes by viral/bacterial inf. disease

17
Q

neonate acute inf. bronchiolitis (AIB) agents

A

Strep agalactiae, E. coli, Klebsiella pneumoniae, Ureaplasma urealyticum, and U. parvum, Chlamydia trachomatis

18
Q

infants/young kids: inf. bronchiolitis (AIB) agents

A

primarily VIRAL:
RSV, hMPV, influenza v, PIV, Ad, HBoV, Rhinovirus, coronavirus
much less bac: B. pertussis, Mycoplasma pneumo, Chlamydia pneumo

19
Q

sig. manifest. of AIB

A

tachypnea, wheezing

NO PNEUMONIA: only scattered wheezing at lung base, but clear lung field

20
Q

bronchitis and bronchiolitis: infectious diseases?

A

may or may not be

21
Q

bronchitis common etiology: viral or bac?

A

viral more common: (RSV, influenza, etc)

bac: Mycoplasma pneumo, Chlamydia pneumo, Bordetella pertussis

22
Q

bronchitis prodrome

A

URT s/s: ha, sore throat, coryza then LRT symps: cough (if prod: sloughing of tracheobronch. epi) +/- bronchospasms, SOB, etc

23
Q

distinct bronchitis negatives

A

NO FEVER (typically, or low)
NO tachycardia, tachypnea
NO pneumonia: clear CXR, no rales, no egophony, *scattered wheezing @ base

24
Q

bronchitis tx: abx?

A

NO! not for immuncomp pts, also NO antivirals
*if Dr. decides on abx: macrolide, may decided on antivirals for susp. influenza otherwise tx: bed, fluids, cough suppressants, expectorants

25
Q

AE-CB and AE-COPD bac pathogens:

A

NTHi**, Moraxella catarrhalis, Strep pneumo

26
Q

AE-CB, AE-COPD: more commonly exacerbated by bacteria or virus?

A

bacteria! freq. a new strain
if virus: influenza*, RSV
other cause: allergies, immpath

27
Q

how to dx AE-CB/COPD

A

bronchoscopy spec. collection: Cx, sens.

>10^3 CFU/mL of agent needs to be det.

28
Q

AE-CB/COPD: abx?

A

no evidence that can prevent, complex decision

29
Q

the most important agent of LRT infections in infants?

characteristics…

A

RSV:
paramyxovirus, F and G surface glycoproteins
strain A* and B (A is the more virulent strain)
danger!: high attack rate (95%), no vaccine

30
Q

ped. pneumonia, bac or viral more common?

A

90% viral (50% of that is RSV)

all kids have been inf. w/ RSV by 2-3 yrs

31
Q

RSV is #1 cause of these in infants

A

LRT diseases: bronchitis, bronchiolitis, pneumo

RSV bronchiolitis can lead to asthma

32
Q

these kids are especially at risk for RSV-caused pulm disease

A

premature and underlying disease(cardiac, resp, cong: pulm HTN, CLD edt.), American Indian infants
and disease will be more severe

33
Q

RSV affects adults as

A

reinfection: common cold, minor URT disease

34
Q

RSV affects elderly w/

A

COPD/CB, immune comp. (organ transplant), LRT disease

*cause bronchopneumonia

35
Q

LBW
VLBW
ELBW

A
36
Q

RSV patho. (bronchiolitis)

A

virus replicates in resp. epi (nasal, throat, bronchi)–>syncytia formation–>necrosis–>sloughing of epi–>inflammation, edema–>inc. sec. or mucus from epi–>obstr. airflow
*immpath exacerbations:
type 1 hypersent. to viral AG (IgE) and rel. of mediators

37
Q

RSV bronchiolitis manifestations (infant)

A

rhinorrhea, cough, NO/LOW GRADE FEVER( + suggests 2 bac inf), dyspnea, cyanosis +/- exp. wheezing/emphysema, hyperinflation, atelectasis
-inc. AP chest diameter, tachy x2, wheezing (whistling), retraction, hepatosplenomegaly

38
Q

RSV bronchiolitis CXR findings

A

inc. AP diameter

loose floppy diaphragm

39
Q

RSV bronchiolitis: self-lim? tx?

A

is self-limited, but do tx

40
Q

reinfect. pres

A

children: sev. rhinitis and pharyngitis (lim. bronchi)
adults: afebrile rhinitis, viral pharyngitis
elderly: ARDS–>viral pneumo

41
Q

RSV bronchiolitis lab collections

A

nasopharyngeal sec, resp asp. w/ epi cells–>DFA/IF/ELISA

42
Q

RSV bronchiolitis tx: antiviral?

A

YES: Ribavirin: broad-spec. antiviral (inhib capping and elong. of viral RNA): improv. O2
also: aeorosolized bronchodil. w/ IV theophylline
corticosteriods, mucolytics (Dornase alpha)
MAINTAIN AIRWAYS keep air moist`

43
Q

give passive immunization therapy to pt. presenting w/ RSV bronchiolitis?

A

NO! it only works for prevention
RSV-IGIV, Anti-RSV MoAb (Palivizumab, Motavizumab)*to replace the IGIV
-give ev. mo. to premie infants/infants w. CLD
*NO VACCINE CANDIDATES

44
Q

hMPV (hum. Metapneumovirus)

A

paramyxovirus

causes dis. sim to RSV, but more mild

45
Q

HBoV (hum. Boca virus)

A

family: Parvoviridae (B19)
causes both URT/LRT inf.
pk incidence MARCH-MAY no inf. Aug-Sept.
-pertussis-like syndrome, diarrhea

46
Q

causes of whooping cough..
where affected?
when?

A

Bordetella pertussis (“pertussis”)
tracheobronchial tree
LATE SUMMER/EARLY FALL
high attack rate! affects infants
/y. kids

47
Q

Bordetella pertussis

A

sm. aerobic G-rod, ox +
Pertussis TOXIN (PT)–>ADP ribosylation of GTP BP–>LYMPHOCYTOSIS–>PT induces prot. Ab
(7-16 d incubation) non-invasive and exotoxin (exc. PT) remain localized

48
Q

hallmark of pertussis

A

LYMPHOCYTOSIS (entrapment in vasc/lymph compartments): 12-20,000 per mm3

49
Q

other factors of pertussis: FHA, Pertactin, TCT

A

FHA (filamentous hemagglytinin): adherence factor, acts w/ PT to induce leukocytosis/ prot. Abs
Pertactin (69 kDa protein): adhesion, ind. Ab
TCT: (Tracheal cytotoxin) + endotoxin induce NO production–>kills ciliated epi cells

50
Q

pertussis epidemics occur every 2-5 yrs despite vaccinations! main reason:

A

circulating strains w. INCREASED VIRULENCE (“breakthru” strains)
other reasons: vaccine failure, failure to comply w/ immun., waning adult immunity

51
Q

the most commonly rep. vaccine-prev. dx in kids

A

Pertussis

52
Q

damage by pertussis exotoxin

A

to ciliated epithelium:
aggr bac in cilia, sticky mucus, PMN accum.
dec. act/loss of cil. epi, prod. of fluid/mucus/eduma

53
Q

does pertussis vaccination/disease confer immunity?

A

YES: prolonged (7-20 yrs) but not permanent

54
Q

Pertussis stages: Cartarrhal

A

highly inf., URT cold-like disease (cough, slight fever, etc) 1-2 wks
Cx/abx effective here but NOT INDICATED
Cx would be done via aspiration > Dacron nasopharyngeal swab, DFA

55
Q

Pertussis stages: Paroxysmal/spasmodic

A

classic, 4-6 wks, 5-10 coughs + mucus then inspirational “whoooop”!, +/- vomiting, apnea, lymphocytosis* in kids, NO FEVER** (unique for bac inf) few syt. signs–> need hosp.

56
Q

Pertussis stages: Convalescent

A

gradual, cough dec. (may continue 2-6 wks)

superimposed viral resp inf. can trigger recurrence

57
Q

differences in adult pertussis

A

paroxysmal cough (>14d), NON-PRODUCTIVE, worse at night, PERIPH. LYMPHOCYTOSIS IS RARE

58
Q

breakthrough pertussis infections in vaccinated children due to

A

high virulence of B. pertussis

59
Q

complications of pertussis

A

secondary bac. pneumo (main cause of mort)
toxic enceph. or anoxia
substn. weight loss/sleeping problems

60
Q

pertussis tx: abx?

A

YES, but only effective @ catarrhal stage

eryth, clarith, azithromycin or TMP-SMZ

61
Q

pertussis: vaccine?

A

YES:
DTP: P: whole cell (SE: fever, NOT rec. for kids w. seizure/neuro risk), 5 doses, last 4-12 yrs
DTaP/dTaP: aP: acellular, 5 doses: 2,4,6 mos then 12-15 mos and 4-6 yrs, 6 yr duration (need adult booster)
protective by 1 wk post vaccine

62
Q

pertussis close contacts: vaccine or abx?

A

abx ppx

63
Q

influenza virus

+ typing

A

orthomyxovirus, 3 types: A, B, C : all have both envelope glycoproteins (H and N), but stereotyping only done for A
(Hemagglutinin: attachment, Neuraminidase: entry into uninf. cells, del of new virus from infected cells)
H1,2,3 and N1,2 (so 6 variants total)

64
Q

antigenic drift

A

minor change: point mutation for H or N genes, occurs in both A and B types
may cause epidemics

65
Q

antigenic shift

A

MAJOR change due to recombin. event for H genes
ONLY in type A (mult. animal hosts–>new viruses for which humans have no herd immunity)
may cause pandemics

66
Q

influenza deaths occur most in…

A

the young and the old (65)

and medically compromised

67
Q

variant viruses

A

typ. circulate in swine but cause sporadic human infection
H1N1v, H3N2v*, H1N2v
*most do not result in human to human spread

68
Q

influenza and kiddos

A

2-10x more susc. than adults BUT typ. less ill and rarely die, so not vaccinated
-serve as reservoirs–>infect adults/elderly (higher mortality)

69
Q

other influenza risk factors (besides age)

A

pulm/CV disease (COPD, CD, CHF), pregnancy, neurological, neumomuscular disorders (aspiration)

70
Q

influenza comprimesse this imp. defense mech of RT

A

destruction of ciliated columnar resp. epi (esp. lg airways)

71
Q

immunity in influenza

A

CMI (CTLs+ IFN prod)–>recovery

Humoral (IgA2 to HA and NA)–>protects against reinfection

72
Q

influenza distinct manifestations

A

ABRUPT onset (no prodrome) (vs. M/C pneumo)
infants 1: URT dis
HALLMARK: PERSISTENT HIGH FEVER (>100)
-non-prod cough, chest discomfort, ha, myalgias, prol. convalescence (1-2 wks)

73
Q

major cause of mortality in influenza

A

secondary bac. pneumonia: asp. of throat flora
orgs: Strep pneumo, Staph aureus, Hib
another complication: primary influenza viral pneumonia

74
Q

influenza: abx?

A

NO! will predispose pt to sec. bac pneumo!!

75
Q

influenza complication in kids admin. ASA

A

Reye’s syndrome : hepatitis, encephalopathy

76
Q

DO NOT give ASA to tx

A

influenza virus A or B, VZV

use acetaminophen instead

77
Q

other complications of influenza

A

CNS (enceph.) or PNS (Guillain-Barre’s)

cerebrovascular, cardiac, OM*, sinusitis

78
Q

influenza lab dx

A

EIA/DFA, Cx, Hemagglutination inhibition

79
Q

vaccination will not end outbreak if..

A

incubation period is LESS than time needed for primary immune response (7-10 days for flu)
ALSO antiviral tx is NOT effective for vaccination (resistance may occur)

80
Q

no longer recommended antivirals for influenza

A

Amantadine, Rimantadine (against A, block m2 protein)

81
Q

influenza antivirals against which types?

inhibit what?

A

A and B (7yo, ppx>5 yrs
(less resistance to Zanamivir)
Oseltamivir (Tamiflu): tx/ppx >1yo

82
Q

influenza: vaccine?

A

YES: “good fit” vaccines, Oct-mid Nov (wanes by summer, Feb for elderly)
heterosubtypic immunity is poor; vacc. ind. can still get flu (diff subtype then vacc. for)

83
Q

influenza vaccine types

A

-killed/inactivated: trivalent (BAA) quad (BBAA)
double strength for oldies, prod. in eggs
-split virus (subvirion): for egg hypersn
-LAIV: intranasal (BA) approv. for 2-49 yo

84
Q

if incubation period is less than time req for primary immune response (7-10d) then..

A

OUTBREAK
1st defense: anti-infective therapy
2nd: vaccination (so ppx can be stopped in about 14 d)
3rd: barrier

85
Q

how to tx influenza preggos

A

if confirmed: Oseltamivir x5 (w/in 2 d onset)

if exposed: ppx Zanamivir or Oseltamivir x 10

86
Q

Bacillus anthracis

A
G+ boxcar, spore forming, non-motile rod
aerobic, catalase +, encapsulated
gamma hemolysis
facultative IC pathogen of *MACROPHAGES*
(member of Bacillus cereus complex) B. cereus gen. non-encaps
87
Q

B. anthracis potency

A

produces exotoxins: cause edema and death

88
Q

anthrax common in US?

A

NO; disease of herbivores, humans dir. contact spores in soil, animals, an. prod
contact w/ sick/dying animals

89
Q

3 types of anthrax

A

cutaneous
GI
pulm(inhal): spores in alv. spaces–>phago by macros–>migr. to mediastinal and peribronchial LNs where spores germinate–>lyse macro
veg. cells prod. exotoxins–>toxemia, hem. LM and massive septicemia (local and syst.)

90
Q

length of anthrax course

A

(10d incubation)

fulminant 3-6 days!

91
Q

anthrax prodrome: specific?

A

no: FEVER, myalgia, N/V
* no rhinitis or pharyngitis (unlike flu)
- ->rapid prog. to alt. ment stat (conf/coma), seizures, resp distr, cyanosis (pulm. consol. may be absent)–>death

92
Q

anthrax hallmark on CXR

A
WIDENING mediastinum and pleural effusions +/- pulmonary involvement
ACUTE onset (unlike influenza, TB, syst. mycoses)
93
Q

other anthrax sp. s/s

A

raised HCT

diaphoresis

94
Q

anthrax tx: abx?

A

YES: oral cipro, doxy for 60 DAYS

95
Q

anthrax: vaccine?

A

YES: for ppx after potential exposure (3 dose)
LAV for animals
AVA (BioThrax): subunit purified Ag (induction of Ab to B. anthracis proteins: PA*, EF, LF)

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