Pneumonia: Causes and Types
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Questions and Answers

Which of the following is the strongest predisposing factor for pneumonia?

  • Age
  • Obesity
  • Smoking
  • Mechanical ventilation or intubation (correct)

    • What percentage of cases of pneumonia caused by S.aureus range from?

    20% to 30%

    Mortality rate for pneumonia can be as high as 50%.

    True

    What are the two categories of pneumonia based on acquisition?

    <p>Community-acquired and hospital-acquired</p> Signup and view all the answers

    Which of the following is a common cause of hospital-acquired pneumonia?

    <p>S.aureus</p> Signup and view all the answers

    The risk for developing pneumonia in the hospital increases by ________ times after a patient is intubated.

    <p>6 to 21</p> Signup and view all the answers

    What can exacerbate the risk of pneumonia in hospitalized patients?

    <p>Wide use of acid-suppressing drugs</p> Signup and view all the answers

    Patients with chronic illnesses are less likely to experience severe manifestations of pneumonia.

    <p>False</p> Signup and view all the answers

    What symptoms are indicative of a more severe clinical presentation in pneumonia when TNF-α and interleukins are released?

    <p>Hypotension and organ dysfunction</p> Signup and view all the answers

    Which of the following symptoms is NOT typically associated with pneumonia?

    <p>Severe abdominal pain</p> Signup and view all the answers

    What test is recommended for hospitalized children suspected of having pneumonia?

    <p>Sputum Gram stain and culture</p> Signup and view all the answers

    What is a characteristic of urinary antigen tests for detecting S.pneumoniae and L.pneumophila in adults with severe CAP?

    <p>Low sensitivity but high specificity</p> Signup and view all the answers

    How soon can urinary antigen tests detect pathogen antigens after initiation of antibiotic therapy for S.pneumoniae?

    <p>Days to weeks</p> Signup and view all the answers

    What is the primary purpose of continually monitoring a patient's clinical status and diagnostic data?

    <p>To support decision-making regarding therapy continuation or adjustment</p> Signup and view all the answers

    Which of the following is NOT a criterion used in the CURB-65 assessment?

    <p>Respiratory distress</p> Signup and view all the answers

    What is indicated for hospitalized patients with severe community-acquired pneumonia regarding MRSA?

    <p>Empiric therapy for MRSA</p> Signup and view all the answers

    What might occur if appropriate therapies are not narrowed or adjusted after evaluating infection status?

    <p>Increased likelihood of drug toxicity or resistance</p> Signup and view all the answers

    Among patients at risk of aspiration, which pathogen is particularly important to consider?

    <p>Staphylococcus aureus</p> Signup and view all the answers

    What is a defining characteristic of community-acquired pneumonia (CAP)?

    <p>Onset outside of the hospital or within 48 hours of hospital admission</p> Signup and view all the answers

    Which group of individuals is more likely to have inadequate respiratory defense mechanisms?

    <p>Immunocompromised individuals such as those with cystic fibrosis</p> Signup and view all the answers

    What effect can lung infections have on the alveolar macrophages?

    <p>Impair their function, leading to potential bacterial pneumonia</p> Signup and view all the answers

    How does alteration of the lung microbiome relate to pneumonia?

    <p>It can evolve to pneumonia, necessitating antimicrobial treatment.</p> Signup and view all the answers

    What is a common feature of multidrug-resistant pathogens in pneumonia?

    <p>Their prevalence is generally higher in hospital-acquired pneumonia.</p> Signup and view all the answers

    Which factor does NOT contribute to the local host defenses of the lower respiratory tract?

    <p>Acid secretion</p> Signup and view all the answers

    What can lead to a secondary bacterial pneumonia following a lung infection?

    <p>Impairment of the antibacterial activity of the lung</p> Signup and view all the answers

    What is a characteristic of atypical pneumonia caused by Mycoplasma pneumoniae?

    <p>Patchy infiltrates on chest x-ray</p> Signup and view all the answers

    Which of the following best describes the respiratory host defenses?

    <p>They comprise both innate and adaptive immunity pathways.</p> Signup and view all the answers

    Which statement about aspiration is correct?

    <p>It can result in aspiration pneumonia or chemical pneumonitis.</p> Signup and view all the answers

    What is the role of mucociliary clearance in respiratory defense mechanisms?

    <p>It helps in the efficient removal of pathogens from the respiratory tract.</p> Signup and view all the answers

    Which of the following correctly describes the effect of mucous in the respiratory tract?

    <p>It minimizes organism attachment and protects the cells.</p> Signup and view all the answers

    What is the primary role of cilia in the lower respiratory tract?

    <p>To move particles upward and out of the tract.</p> Signup and view all the answers

    Which antibiotic is preferred for treating methicillin-susceptible Staphylococcus aureus (MSSA) infections in community-acquired pneumonia?

    <p>Cefazolin</p> Signup and view all the answers

    What additional antibiotic coverage should patients in a hospital with an MRSA prevalence of 20% or greater receive?

    <p>Vancomycin or Linezolid</p> Signup and view all the answers

    Which antibiotic is categorized as an alternative for methicillin-susceptible strains but is less preferred for pneumonia treatment?

    <p>Clindamycin</p> Signup and view all the answers

    In patients at risk for multi-drug resistant (MDR) HAP, what type of coverage should they also receive?

    <p>MRSA coverage and a second antipseudomonal agent</p> Signup and view all the answers

    What is the most common gram-negative cause of pneumonia?

    <p>H.influenzae</p> Signup and view all the answers

    Which of the following is an acceptable treatment alternative for MRSA pneumonia?

    <p>Quinupristin-dalfopristin</p> Signup and view all the answers

    What type of antibiotic regimens should empiric treatment for hospital-acquired pneumonia include?

    <p>At least one antibiotic with coverage against gram-negative and specific pathogens</p> Signup and view all the answers

    What is the significance of a high MIC value in penicillin-intermediate strains when considering amoxicillin treatment?

    <p>It warrants the use of high-dose amoxicillin.</p> Signup and view all the answers

    Study Notes

    Pneumonia

    • Inflammation of one or both lungs that affects the air sacs, or alveoli, which fill with fluid or pus.
    • Leading infectious cause of death in children and adults in the United States.
    • Affects people of all ages, with the most severe clinical manifestations in the very young, elderly, and chronically ill.
    • Occurs throughout the year, with seasonal variations in the relative incidence of disease.
    • Caused by various viral and bacterial pathogens.
    • Classified as either community-acquired or hospital-acquired.

    Hospital-acquired Pneumonia (HAP)

    • Occurs after 48 or more hours of endotracheal intubation.
    • Risk of developing HAP increases by 6 to 21 times after intubation.
    • Strongest predisposing factor is mechanical ventilation or intubation.
    • Often caused by gram-negative aerobic bacilli or Staphylococcus aureus.
    • Patients with longer hospital admissions or IV antibiotic use within 90 days preceding HAP are more likely to have multidrug-resistant (MDR) organisms.
    • Mortality rate can be as high as 50%.

    Ventilator-associated Pneumonia (VAP)

    • A subtype of hospital-acquired pneumonia.
    • Exacerbated by acid-suppressing drugs like H2-receptor blocking agents and proton pump inhibitors.
    • More commonly caused by Staphylococcus aureus (20-30%) with a higher incidence of multidrug resistance.

    Pathogenesis

    • In healthy individuals, the respiratory host defenses effectively remove respiratory pathogens before infection occurs.
    • These defense mechanisms include both innate and adaptive immunity pathways.
    • Immunocompromised individuals lack robust defense mechanisms and are more susceptible to pneumonia, such as those with cystic fibrosis or prolonged neutropenia.
    • Lung infections can suppress antibacterial activity by impairing alveolar macrophage function and mucociliary clearance, making the lung more vulnerable to secondary bacterial pneumonia.
    • Any alteration of the normal lung microbiome by infection or disease can evolve to pneumonia requiring antimicrobial treatment.

    Community Acquired Pneumonia (CAP)

    • Majority of cases caused by Streptococcus pneumoniae (20-30%)
    • Community-acquired or hospital acquired
    • Can be caused by bacteria, atypical organisms, or viruses

    Pathogenesis

    • Respiratory defenses include both innate and adaptive immunity
    • Defenses are preserved in healthy individuals
    • Immunocompromised people have weakened defenses (e.g., cystic fibrosis, prolonged neutropenia)
    • Lung infections can suppress antibacterial activity by:
      • Impairing alveolar macrophage function
      • Decreasing mucociliary clearance

    Pathophysiology

    • CAP: Onset is outside the hospital or within 48 hours of hospital admission
    • Local host defenses of the lower respiratory tract:
      • Mucus lining
      • Cilia
      • Antibodies (IgA, IgM, IgG)
      • Complement
      • Alveolar macrophages
    • Aspiration can lead to aspiration pneumonia or chemical (acid) pneumonitis
    • Systemic release of TNF-α and interleukins (ILs)-1 and -6 can lead to severe symptoms:
      • Hypotension
      • Organ dysfunction
      • Septic or septic-shock

    Clinical Presentation

    • Fever, chills, malaise (constitutional symptoms)
    • Cough, increased sputum production, dyspnea (respiratory symptoms)
    • Abrupt onset
    • Rust-colored sputum or hemoptysis
    • Pleuritic chest pain
    • Dyspnea

    Diagnostics

    • Sputum Gram stain and culture recommended for hospitalized children who can produce a sample
    • Blood cultures recommended for moderate/severe CAP
    • Urinary antigen tests available for S. pneumoniae and L. pneumophila, recommended in adults with severe CAP
    • High specificity (90-99%) but lower sensitivity (50-80%)
    • Can detect pathogen antigen days to weeks after starting antibiotic therapy

    Treatment

    • Continued monitoring of patient's clinical status and diagnostic data
    • Decision to continue, narrow, alter, or discontinue therapy based on data
    • CURB-65 and CRB-65 are commonly used severity assessments

    Risk Factors for CAP

    • Previous hospitalization within the past month
    • Use of broad-spectrum antibiotics in the past 7 days
    • Severe underlying bronchopulmonary disease
    • Malnutrition
    • Chronic use of steroids >15 mg/day for at least 2 weeks

    Empiric Therapy

    • Based on likely pathogens
    • No P. aeruginosa risk:
      • Ceftriaxone 2g IV q24h OR Ertapenem 1g IV q24h PLUS Azithromycin 500mg IV daily OR Levofloxacin 750mg IV daily
    • Risk for P. aeruginosa:
      • Piperacillin-tazobactam OR Cefepime PLUS Azithromycin 500mg IV daily OR Levofloxacin 750mg IV daily
    • High-dose amoxicillin (3 g/day) may be used for penicillin-intermediate strains (MIC = 4 mg/L)

    MRSA Coverage for Hospitalized Patients with Severe CAP

    • Consider MRSA coverage in the following cases:
      • Requirement for intensive care unit (ICU) admission
      • MRSA prevalence of 20% or greater in the hospital or unit

    Specific MRSA Regimen

    • Vancomycin or Linezolid are the preferred treatments
    • Alternatives include:
      • Quinupristin-dalfopristin
      • Ceftaroline
      • Sulfamethoxazole-trimethoprim
      • Clindamycin

    Gram-Negative Pathogens

    • Haemophilus influenzae is the most common gram-negative cause of HAP.

    Hospital Acquired Pneumonia (HAP)

    • Most HAP cases are caused by gram-negative bacilli:
      • P. aeruginosa
      • Enterobacteriaceae
      • S. aureus
    • Empiric regimens should include at least one antibiotic with coverage against these pathogens:
      • An antipseudomonal, antistaphylococcal β-lactam (e.g., piperacillin/tazobactam or cefepime)
      • An antipseudomonal, antistaphylococcal fluoroquinolone (e.g., levofloxacin)
    • Patients with MDR HAP risk factors (e.g., recent IV antibiotics, structural lung disease) should receive coverage for MDR gram-negative bacilli.

    Methicillin-Susceptible Staphylococcus aureus (MSSA)

    • Empiric therapy:
      • Nafcillin or oxacillin are the preferred agents
      • Dicloxacillin is preferred in the community setting
      • Cefazolin is an alternative
      • Clindamycin or vancomycin can also be used, but are not preferred

    Directed Therapy for Important Gram-Negative Pathogens

    • Haemophilus influenzae is the most common gram-negative cause of CAP.
    • Targeted therapy based on culture and sensitivity testing.

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    Pneumonia PDF

    Description

    This quiz covers the essential aspects of pneumonia, including its definition, causes, and classifications. Learn about pneumonia's impact on various age groups and the specifics of hospital-acquired pneumonia. Test your knowledge on this critical health issue affecting millions worldwide.

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