Exam 3- Lower Respiratory Tract infections (pneumonia) Flashcards by TheOneandOnly Ash

Where does the split occur that divides upper respiratory tract infections from lower respiratory tract infections?

The split occurs at the neck

Anything above the neck is an URTI
Anything below the neck is a LRTI

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Where does pneumonia typically occur?

The alveoli of the lungs

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What are the 4 mechanisms of host defense against respiratory tract infections?

Nasopharynx
Trachea/Bronchi
Oropharynx
Alveoli/Terminal Airways

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What are examples of nasopharynx host defense mechanisms?

These are defenses associated with the nose and areas around the nose

*Nasal hair
-Anatomy of upper airways
-IgA secretion
-Mucociliary Apparatus
-Fibronectin

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What are examples of trachea/bronchi host defense mechanisms?

These are defenses of the trachea and bronchi found in the lungs, they are used to DECREASE BACTERIAL LOAD

*Cough
*Epiglottic reflex (epiglottic closes to prevent aspiration of particles down the trachea)
-Anatomy of conducting airways
-Mucociliary apparatus
-Immunoglobulin

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What are examples of oropharynx host defense mechanisms?

These are associated with the mouth

*Saliva
*Slough epithelial cells (shedding, helps get rid of attached bacteria to be removed by the saliva)
-Complement production

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What are examples of alveoli/terminal airway host defense mechanisms?

Found in the lung, these are sites associated with gas exchange. Most defenses are immune-mediated

-Alveolar lining fluid
-Cytokines
-Macrophages +PMNs
-Cell-mediated immunity (B and T cells)

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What are the 4 reasons why host defense mechanisms against a pathogen may not work?

-*Pathogen-mediated
(mutations increase ability to infect)

-Host Interventions
(smoking, alcohol)

-Defenses gone wrong
(alveolar amcrophages)

Host disease states
(immunosuppression, etc)

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What host interventions may reduce innate defense mechanisms against pathogens and how do they do this?

Smoking- decreases mucociliary apparatus (cilia), increases mucus

Alcohol- decreases epiglottic reflux, increasing likelihood of aspiration

Altered level of consciousness

Endotracheal tubes

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What host disease states may decrease innate defense mechanisms against pathogens?

*Immunosuppression
-Diabetes
-Asplenia
-Elderly

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What is the definition of “Community-Acquired Pneumonia”?

Pneumonia that developed outside of the hospital OR within 48 hours of hospital admission

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What is the most common cause of infection-related hospitalization and mortality?

Community Acquired Pneumonia

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What are the 3 mechanisms of pathogenesis of Community-Acquired Pneumonia?

Aspiration
-most common
-common during sleep or in disorders that impair consciousness and depress gag reflex resulting in increased inoculum

Aerosolization
-Direct inhalation of pathogen (virus)
-Droplet nuclei= particles containing pathogen

Bloodborne
-Translocate to pulmonary site
-Uncommon

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I-Clicker: Which microorganism class is the most common pathogenic organism for CAP?
A. Fungus
B. Bacteria
C. Virus
D. Protozoa

C. Virus

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True or False: Viruses normally resolve by themselves and do not require antibiotics

True
-although viruses are the most common cause of CAP, we are going to be focusing on the bacterial causes

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What are the common bacterial pathogens of CAP?

Streptococcus pneumonia (G+)

Haemophilus influenzae (G-)

*Atypical Pathogens:
-Mycoplasma pneumoniae
-Legionella pneumophila
-Chlamydia pneumoniae

Staph aureus (in more serious infections)

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What are the atypical pathogens that are common in CAP?

Mycoplasma pneumonia
Legionella pneumophila
Chlamydia pneumoniae

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What 3 drug classes cover atypical pathogens?

Fluoroquinolones (“flox”)

Macrolides (“Eryth, Clarith, Azith”)

Tetracyclines (“Tetra, Doxy, Mino”)

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What are the typical characteristics of Streptococcus pneumoniae?

Increased prevalence + severity in patients with medical condition risk factors (asplenia, diabetes, immunocompromised, etc)

Resistance to penicillins + macrolides is concerning. Risks include:
-Old (>65) or young (<6)
-Prior abx use
-Co-morbid conditions
-Day care
-Recent hospitalization
-Close quarter living

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What are the typical characteristics of Mycoplasma pneumoniae?

Atypical bacteria (not identified on gram stain)

Spread by person-to-person contact (higher risk in close-quarter living)

2-3 week incubation with slow symptom onset

Imaging is more pronounced with patchy, interstitial infiltrates

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What are the typical characteristics of Legionella pneumophila?

Atypical pathogen

*Found in soil + water

Spread by aerosolization

Risk factors: older males, bronchitis, smokers, immunocompromised

Multisystem involvement is common, leads to more severe symptoms

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When it is believed that a CAP patient has a Staph aureus infection, what test needs to be done?

MRSA nasal PCR

95-99% negative predictive value for MRSA in CAP
But only 56.8% positive predictive value

*Does a great job of telling you that you do NOT have MRSA

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What is the common symptom presentation of CAP?

Sudden onset of:
-Fever
-Chills
-Pleuritic chest pain
-Dyspnea
-Productive cough

*Note that Mycoplasma and Chlamydia pneumoniae have a gradual onset and lower severity

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What is the symptom presentation of elderly patients with CAP?

Classic symptoms may be absent

*More likely to have decreased functional status, weakness, mental status changes

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What are the common vitals of someone with CAP?

Febrile Tachycardic **Hypotensive** Tachypnea (rapid breathing)

What diagnostic tests may we run on a patient with CAP?

Chest Radiography (Chest X-ray) *all patients Sputum Characteristics (Gram stain) Blood Culture (*2 sets*) Respiratory cultures are controversial, only used for severe patients

The appearance of dense lobar consolidation or infiltrates on a Chest x-ray done on a patient with CAP is suspicious for what?

Bacterial origin

The appearance of patchy, diffuse, interstitial infiltrates on a Chest X-ray done on a patient with CAP is suspicious for what?

Atypical or viral pathogens

When doing a gram stain, we only evaluate samples that have what?

>25 PMNs <10 epithelial cells

What kind of organism is S. pneumoniae (aka what result on a Gram stain would make us suspicious of this organism)?

Gram + Diplococci (pairs/chains)

What kind of organism is H. influenzae (aka what result on a Gram stain would make us suspicious of this organism)?

Gram - Coccobacilli (note that Haemophilus species are the only organisms that are classified as coccobacilli)

When are respiratory cultures used in CAP?

ONLY in severe patients -note that use is controversial because false negatives are common

What are the criteria for diagnosing Severe CAP?

Major Criteria (Need 1): -Septic shock requiring vasopressors -Respiratory failure requiring mechanical ventilation Minor Criteria (Need 3 or more): -Resp Rate >/= 30bpm -Pa/Fl /= 20) -Leukopenia (WBC < 4000) -Thrombocytopenia (Plt < 100,000) -Hypothermia (<36C) -Hypotension requiring aggressive fluids

How can getting procalcitonin levels help us in CAP?

It is a biomarker typically elevated in bacterial infections *DO NOT USE to determine if antibiotics are needed* **Useful to help guide duration of therapy**

What are the 2 Clinical Prediction Tools that can be used in CAP?

Pneumonia Severity Index (PSI) CURB-65

What are the 4 supportive treatment options that can be given to CAP pts?

Humidified Oxygen Bronchodilators Fluids Chest Physiotherapy

What is the treatment for Empiric Therapy: Outpatient: No Comorbidities?

Pick 1: Amoxicillin (strep pneumo) Doxycycline (atypical) Azithromycin (not monotherapy)

What is the treatment for Empiric Therapy: Outpatient: With Comorbidities?

Monotherapy: Respiratory Fluoroquinolone (Levofloxacin, Moxifloxacin) *Combo Therapy: Beta-Lactam + Macrolide/Doxycycline preferred beta-lactams: -Amox/Clav -Cefpodoxime -Cefuroxime

What is the treatment for Empiric Therapy: Inpatient: Non-Severe CAP: No MRSA/Pseudomonas risks

Monotherapy: Respiratory Fluoroquinolone (Levofloxacin, Moxifloxacin) Combo Therapy: Beta-Lactam + Macrolide preferred beta-lactams: -Ampicillin/Sulbactam -Ceftriaxone *note that doxycycline may be used if FQ or macrolide contraindicated

What is the treatment for Empiric Therapy: Inpatient: Severe CAP: No MRSA/Pseudomonas risk factors

Combination therapy only: Respiratory FQ + Beta-lactam or Beta-Lactam + Macrolide* *beta-lactams recommended: -Ampicillin/Sulbactam -Ceftriaxone *note that doxycycline may be used if FQ or macrolide contraindicated

What are the Comorbidities that need to be take into consideration for CAP outpatient empiric therapy?

Chronic Heart, Lung, or Renal disease Diabetes Alcoholism Malignancy Asplenia/Immunosuppression

What are the risk factors for MRSA?

2-14 days post-influenza Previous MRSA respiratory infection Previous hospitalization and use of IV abx in last 90 days

If a CAP patient needs MRSA coverage, what should we add to their regimen?

Vancomycin or Linezolid

What are the risk factors for Pseudomonas?

Previous Pseudomonas respiratory infection Previous hospitalization and use of IV abx within last 90 days

If a CAP patient needs pseudomonas coverage, what should we add to their regimen?

Piperacillin/Tazobactam or Cefepime or Meropenem

What is the preferred CAP therapy for Streptococcus pneumoniae?

Pen-susc: Penicillin G; Amoxicillin Pen-resist: Ceftriaxone, Resp FQ

What is the preferred CAP therapy for Haemophilus influenzae?

2nd/3rd gen cephalosporin Unasyn Augmentin

What is the preferred CAP therapy for the atypicals: Mycoplasma pneumoniae and Chlamydia pneumoniae?

Macrolide Doxycycline

What is the preferred CAP therapy for Legionella pneumophila?

FQ Azithromycin

What drug class is not recommended for adults with CAP?

Corticosteroids

What is the recommended duration of CAP therapy?

*Need to ensure clinical stability first* Minimum of 5 days

How is aspiration pneumonia different than other forms of pneumonia?

It is not -there is no definition to differentiate it against pneumonia

If a patient has aspiration pneumonia, what consideration should we make with their treatment?

Anaerobic coverage is NOT NEEDED (recommended against) *unless a lung abscess or empyema (pus development in plural space) is present

In what case would both Macrolide and Fluoroquinolone therapy for a CAP patient be contraindicated, pushing the use of Doxycycline instead?

Prolonged QTc interval (>460 ish)

What is the definition of hospital acquired pneumonia (HAP)?

Pneumonia occurring >/= 48 hours after hospital admission

What is the definition of ventilator associated pneumonia (VAP)?

Pneumonia occurring >/= 48 hours after endotracheal intubation

What are the common pathogens in HAP/VAP?

Aerobic Gram - Bacilli -Pseudomonas Acinetobacter baumannii Staphylococcus aureus *MRSA is a greater concern in this population

What testing should be conducted in HAP/VAP patients?

Respiratory Cultures* -all patients -note that this is different from CAP Blood cultures -all patients

In a respiratory culture for HAP, how many organisms need to be present for it to be considered an infection?

10,000 (>/= 10^3)

What is the risk factor for developing multi-drug resistant HAP?

Prior IV antibiotic use within 90 days

What are the risk factors for developing multi-drug resistant VAP?

Prior IV antibiotic use within 90 days Septic shock at time of diagnosis Acute respiratory distress syndrome prior to diagnosis Acute renal replacement therapy prior to onset >/= 5 days of hospitalization prior to diagnosis

What is the risk factor for MRSA and Pseudomonas with HAP/VAP?

Prior IV antibiotic use within 90 days

If a HAP/VAP patient has Pseudomonas, what treatment options could they receive?

Carbapenems Broad-spectrum beta-lactams Fluoroquinolones

What are the risk factors for MRSA with HAP that requires Empiric MRSA Therapy?

Prior IV antibiotic use within 90 days ICUs with > 10-20% MRSA isolates Treatment where prevalence is unknown

What drug choices do we have for MRSA Empiric Therapy in HAP?

Vancomycin Linezolid

What are the risk factors for Pseudomonas with HAP that requires Empiric Therapy?

Prior IV antibiotic use within 90 days ICUs with >10% of isolates resistant Treatment where resistance rates are unknown

What drug choices do we have for BOTH Pseudomonas Empiric Therapy AND Patients not at high risk for mortality (no ventilation/ no septic shock) in HAP?

Piperacillin-Tazobactam Cefepime Imipenem Meropenem Levofloxacin (therapy is the same for both)

What drug choices do we have for treatment of High Risk for Mortality (ventilated or have septic shock) with MRSA Risk in HAP?

Pick 2 from Different Categories: Piperacillin-Tazobactam Cefepime Imipenem Meropenem Levofloxacin **Tobramycin/Amikacin (note that this is the same as Pseudomonas and non-high risk except for addition of tobramycin/amikacin and you have to pick 2)

What are the therapy options for Empiric VAP Therapy?

*Note: choose 2 anti-pseudomonals is risk factors for resistance are present Otherwise choose one: -Piperacillin-Tazobactam Cefepime -Imipenem -Meropenem -Levofloxacin -Tobramycin/Amikacin

What antibiotic should never be used in lower respiratory tract infections (pneumonia)?

Daptomycin -it is inactivated by surfactants

What is the typical duration of HAP/VAP therapy?

7-day duration if clinically stable

Exam 3- Lower Respiratory Tract infections (pneumonia) Flashcards

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