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PHRM 865 > Lower Respiratory Tract Infections > Flashcards

Lower Respiratory Tract Infections Flashcards

(63 cards)

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1
Q

What are the host defense mechanisms?

A

nasopharynx, trachea/bronchi, oropharynx, alveoli/terminal airways

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2
Q

Host defense mechanisms - nasopharnyx

A

nasal hair (net to capture bacteria), anatomy of upper airways, IgA secretion, mucociliary apparatus, fibronectin (bind to bacteria to prevent binding to host cells)

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3
Q

Host defense mechanisms - trachea/bronchi

A

cough, epiglottic reflex, anatomy of conducting airways, mucociliary apparatus, immunoglobulin
these reflexes decrease bacteria load

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4
Q

Host defense mechanisms - oropharynx

A

saliva, slough epithelial cells, complement production
get rid of attached bacteria

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5
Q

Host defense mechanisms - alveoli/terminal airways

A

alveolar lining fluid, cytokines, macrophages + PMNs, cell-mediated immunity
increase binding of bacteria to host cells

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6
Q

What happens when the body does not do its job?

A

pathogen-mediated
host interventions
defenses gone wrong
host disease states

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7
Q

Pathogen-mediated

A

surface adhesions, pili, exotoxins, enzymes (fight immune cells)
most significant

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8
Q

Host interventions

A

smoking, alcohol, altered level of consciousness, endotracheal tubes
alcochol and altered level of consciousness decrease the epiglottic reflex

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9
Q

Defenses gone wrong

A

alveolar macrophages: phagocytosis + cytokine release –> recruit neutrophils –> acidic and hypoxic environment –> reduced phagocytosis

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10
Q

Host disease states

A

immunosuppression, diabetes, asplenia, elderly

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11
Q

What is community acquired pneumonia?

A

pneumonia that developed outside of the hospital or within the first 48 hours of hospital admission

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12
Q

Community-acquired pneumonia pathogenesis

A

aspiration, aerosolization, bloodborne

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13
Q

Community-acquired pneumonia pathogenesis - aspiration

A

most common pathway for bacterial pneumonia; organisms usually cleared if host defenses functioning properly
disorders that impair consciousness and depress gag reflex results in increased inoculum

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14
Q

Community-acquired pneumonia pathogenesis - aerosolization

A

direct inhalation of pathogen
droplet nuclei = particles containing pathogen

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15
Q

Community-acquired pneumonia pathogenesis - bloodborne

A

translocate to pulmonary site; extremely unlikely

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16
Q

Which microorganism is the most common pathogen organism for CAP?

A

virus

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17
Q

What are the common bacterial pathogens for CAP?

A

streptococcus pneumoniae (most common) - GP
haemophilus influenzae - GN
atypical pathogens: mycoplasma pneumoniae, legionella pneumophila, chlamydia pneumonieae
staphylococcus aureus - GP

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18
Q

Streptococcus pneumoniae in CAP

A

increased prevalence and severity in certain patients: asplenia, DM, immunocompromised, HIV, chronic cardiopulmonary/renal disease
risk factors for drug resistance: age (<6 or >65), prior antibiotic therapy, co-morbid conditions, day care, recent hospitalization, and close quarters - penicillin resistance ~3%, macrolide ~40-50%

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19
Q

Mycoplasma pneumoniae in CAP

A

atypical bacteria - lacks cell wall
spread by person-to-person contact; 2-3 week incubation period followed by slow onset of sx: persistent, non-productive cough, fever, HA, sore throat, rhinorrhea, N/V, arthralgia
imaging: patchy, interstitial infiltrates

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20
Q

Legionella pneumophila in CAP

A

atypical pathogen - found in water + soil
spread by aerosolization
increased risk: older males, chronic bronchitis, smokers, and immunocompromised
multisystem involvement: high fevers, relative bradycardia, multi-lobar involvement, mental status change, increased LFTs + SCr

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21
Q

Staphylococcus aureus in CAP

A

low prevalence
risk factors for MRSA: ~2-14 days post-influenza, previous MRSA infection/isolation, previous hospitalization, previous use of IV antibiotics
important to get MRSA nasal PCR!!! - has 95-99% NEGATIVE predictive value for MRSA in CAP! - tells you we don’t have MRSA

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22
Q

Risk factors for certain pathogens - alcoholism

A

s. pneumoniae, anaerobes, k. pneumoniae

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23
Q

Risk factors for certain pathogens - COPD/smoker

A

s. pneumoniae, h. influenzae, moraxella cattarhalis, legionella spp

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24
Q

Risk factors for certain pathogens - post influenza pneumonia

A

s. pneumoniae, s. aureus, h. influenzae

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25
Risk factors for certain pathogens - structural lung disease
p. aeruginosa, s. aureus
26
Risk factors for certain pathogens - recent antibiotic exposure
s. aureus, p. aeruginosa
27
Clinical presentation of CAP
sudden onset of fever, chills, pleuritic chest pain, dyspnea, productive cough; gradual onset with lower severity for mycoplasma and clamydia pneumoniae in elderly pts: classic sx may be absent (afebrile, mild leukocytosis) and more likely to have decrease in functional status, weakness, and mental status changes vitals: febrile, tachycardia (HR > 100), hypotensive (SBP < 90), tachypnea (RR > 30)
28
Chest radiography in CAP
recommended for all pts with suspicion for CAP dense lobar consolidation or infiltrates = suspicion for bacterial origin patchy, diffuse, intersitial infiltrates = atypical or viral pathogens
29
Sputum characteristics in CAP
color, amount, consistency, and odor observed
30
Microbiology testing and other markers for CAP
respiratory culture: controversial blood culture: get 2 sets! WBC with differential, SCr, BUN, electrolytes, LFTs, pulse oximetry, oxygen saturation (less than 90), urinary antigen tests (s. pneumoniae, legionella pneumophila), nasopharyngeal PCR swabs (MRSA)
31
Severe CAP
septic shock requiring vasopressors - resp rate >/=30 bpm, multilobal infiltrates, confusion/disorientation respiratory failure requiring mechanical ventilation - uremia (BUN >/=20 mg/dL), leukopenia (WBC < 4000 cell/uL), thrombocytopenia (Plt < 100,000/uL), hypothermia, hypotension requiring aggressive fluids
32
Other tools for CAP
procalcitonin: biomarker typically elevated in presence of bacterial infection should NOT be used to determine need for antibiotics for CAP clinical prediction tools: pneumonia severity index, CURB-65
33
CAP treatment - supportive measures
humidified oxygen (need O2 in blood), bronchodilators (open pathways), fluids, chest physiotherapy (beating on someone's back)
34
CAP empiric therapy - outpatient with no comorbidities
health outpatient adults WITHOUT comorbidities or risk factors for antibiotic resistance: amoxicillin, doxycycline, macrolide resistance (<25%) - azithromycin (do NOT use macrolide monotherapy)
35
CAP empiric therapy - outpatient with comorbidities
outpatient adults with comorbidities: chronic heart, lung, or renal disease, DM, alcoholism, malignancy, asplenia, or immunosuppression monotherapy: respiratory fluoroquinolone - levofloxacin or moxifloxacin combo therapy: beta lactam + macrolide or doxycycline (more preferred due to resistance) (beta lactams recommended: amoxicillin clavulanate, cefpodoxime, or cefuroxime)
36
CAP empiric therapy - inpatient non-severe
no MRSA/pseudomonas aeruginosa risk factors monotherapy: respiratory fluoroquinolone - levofloxacin, moxifloxacin combo therapy: beta-lactam + macrolide (beta-lactams recommended: ampicillin/sulbactam, ceftriaxone)
37
CAP empiric therapy - inpatient severe
no MRSA/pseudomonas aeruginosa risk factors combo therapy: respiratory fluoroquinolone + beta-lactam or beta-lactam + macrolide (recommend this one) (beta-lactams recommended: ampicillin/sulbactam, ceftriaxone)
38
CAP empiric therapy - inpatient if MRSA risk factors are present
risk factors: ~2-14 days post-influenza; previous MRSA respiratory infection/isolation; previous hospitalization and use of IV antibiotics within last 90 days MRSA coverage: vancomycin or linezolid
39
CAP empiric therapy - inpatient if pseudomonas aeruginosa risk factors are present
risk factors: previous pseudomonas aeruginosa respiratory infection; previous hospitalization and use of IV antibiotics within last 90 days pseudomonas coverage: piperacillin/tazobactam, cefepime, meropenem
40
What about corticosteroids in CAP?
not recommended with non-severe CAP, suggest not to use with severe CAP, suggest not to use for severe influenza pneumonia only recommended when patient has CAP AND septic shock!
41
Duration of CAP therapy
continue antibiotics until clinically stable for a min of 5 total days
42
What is clinical stability?
temp /= 90 mmHg, arterial )2 saturation >/= 90%, baseline mental status
43
Aspiration pneumonia
no definition to differentiate aspiration pneumonia vs pneumonia recommend against anaerobic coverage unless lung abscess or empyema present
44
What is hospital acquired pneumonia?
pneumonia occurring >/= 48 hrs after hospital admission
45
What is ventilator-associated pneumonia?
pneumonia occurring >/= 48 hrs after endotracheal intubation
46
HAP/VAP epidemiology and impact
HAP: one of the most common hospital-acquired infections VAP: increases utilization of healthcare resources from prolonged length of mechanical ventilation and hospitalization
47
HAP/VAP pathogenesis
micro-aspiration of oropharyngeal secretions that are colonized with bacteria aspiration of esophageal/gastric contents hemaogenous spread from another source direct inoculation into airways via intubation mechanical ventilation - endotracheal tube bypasses all host defenses and decreases LRT defenses
48
Risk factors for HAP/VAP
advanced age, severity of comorbid diseases (uncontrolled A1c, asthma, COPD), duration of hospitalization, endotracheal intubation, nasogastric tube, altered mental status, surgery, previous antimicrobial therapy
49
Diagnosis of HAP/VAP
no gold standard for diagnosis timing: important for defining hospital-acquired infection, impacts choice of antibiotic (48hrs from admission) typical presentation: new lung infiltrate + clinical signs/sx: new onset fever, purulent sputum, leukocytosis, decline in oxygenation
50
Common pathogens for HAP/VAP
aerobic gram-negative bacilli: pseudomonas aeruginosa, enteric gram-negative bacilli, aceintobacter baumannii staphylococcus aureus: MRSA great concern in this population
51
Microbiology testing for HAP/VAP
respiratory cultures: obtain for all pts, non-invasive > invasive blood cultures: obtain from all pts
52
Risk factors for multi-drug resistant HAP
prior IV antibiotic use within 90 days
53
Risk factors for multi-drug resistant VAP
prior IV antibiotic use within 90 days, septic shock at time of diagnosis, acute respiratory distress syndrome, acute renal replacement therapy, >/= 5 days hospitalization prior to diagnosis
54
Risk factors for MDR in HAP/VAP - MRSA and pseudomonas aeruginosa
MRSA: prior IV antibiotic use within 90 days pseudomonas: prior IV antibiotic use within 90 days; carbapenems, broad-spectrum beta-lactams, fluoroquinolones
55
Empiric therapy principles for HAP/VAP
should be based on locacl distribution of pathogens and susceptibility (utilize yearly antibiogram) goal: provide broad spectrum antibiotics while avoiding unnecessary harms of inappropriate coverage
56
Empiric therapy - antibiotic choice for HAP/VAP - MRSA coverage
risk factors: typical risk factors for MRSA, ICUs where > 10-20% MRSA isolates, treatment where prevalence is unknown vancomycin or linezolid
57
Empiric therapy - antibiotic choice for HAP/VAP - pseudomonas aeruginosa coverage
risk factors for resistance: ICUs where >10% of isolates resistant, treatment where resistance rates are unknown piperacillin-tazobactam, cefepime, imipenem, meropenem, or levofloxacin
58
Empiric therapy - HAP - not at high risk for mortality
not at high risk for mortality: not on ventilatory support or septic shock goal: provide coverage for MSSA + pseudomonas aeruginosa piperacillin-tazobactam, cefepime, imipenem, meropenem, or levofloxacin
59
Empiric therapy - HAP - not at high risk for mortality but MRSA risk
goal: provide coverage for MRSA + pseudomonas aeruginosa piperacillin-tazobactam, cefepime, imipenem, meropenem, or levofloxacin PLUS vancomycin or linezolid
60
Empiric therapy - HAP - high risk for mortality and MRSA risk
goal: provide coverage for MRSA + MDR pseudomonas aeruginosa pick 2 different classes: piperacillin-tazobactam, cefepime, imipenem, meropenem, levofloxacin, or tobramycin/amikacin (should be 1 beta-lactam and 1 non-beta-lactam) PLUS vancomycin or linezolid
61
Empiric therapy - VAP
goal: provide coverage for MRSA + pseudomonas aeruginosa when to choose 2 anti-pseudomonals: risk factors for resistance piperacillin-tazobactam, cefepime, imipenem, meropenem, levofloxacin, or tobramycin/amikacin PLUS vancomycin or linezolid
62
Non-beta lactam considerations
NEVER use daptomycin for LRTIs aminoglycosides recommended against as monotherapy tigecycline associated with increased mortality
63
Duration for HAP/VAP
recommend 7-day duration if clinically stable

PHRM 865 (61 decks)

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