Pneumonia: CAP vs HAP Overview

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Questions and Answers

Which of the following is a criterion for the CURB-65 assessment?

Presence of chest pain

Elevated blood glucose levels

Respiratory rate ≥30 breaths/min (correct)

Body temperature above 102°F

What is the main goal of balancing therapy in patient treatment?

To ensure the maximum dosage of antibiotics is administered

To eliminate all pathogens regardless of toxicity

To prevent unnecessary drug toxicity and resistance (correct)

To prioritize rapid treatment over thorough monitoring

For patients at risk of P. aeruginosa, what antibiotic regimen is suggested?

Ceftriaxone 2g IV q24h

Piperacillin-tazobactam 4.5g IV q8h (correct)

Ertapenem 1g IV q24h

Meropenem 1g IV q8h

Which of the following conditions would indicate the need for empiric therapy for MRSA in hospitalized patients with severe CAP?

Requirement for intensive care unit Signup and view all the answers

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

To support decisions on whether to continue or alter therapy Signup and view all the answers

Which antibiotic regimen is recommended for the treatment of Pseudomonas aeruginosa in patients with pneumonia?

Cefepime 2g IV every 8-12 hours Signup and view all the answers

What is the maximum duration recommended for treating S.aureus or P.aeruginosa with concomitant bacteremia?

28 days Signup and view all the answers

In cases of suspected MRSA pneumonia, which additional treatment is recommended?

Vancomycin loading dose followed by a maintenance dose Signup and view all the answers

What does CLSI recommend for isolates of S.pneumonia suspected to be susceptible to intravenous penicillin?

Narrow-spectrum penicillin or cephalosporin antibiotic Signup and view all the answers

Which of the following is NOT recommended for treating MRSA bacteremia associated with a pulmonary source?

Linezolid or Clindamycin monotherapy Signup and view all the answers

Which antibiotic should be considered in cases where there is a severe beta-lactam allergy?

Clindamycin Signup and view all the answers

Which symptom is NOT typically associated with necrotizing or cavitary infiltrates in pneumonia?

Euphoria Signup and view all the answers

What dosage of Levofloxacin IV is recommended in pneumonia treatment?

750mg daily Signup and view all the answers

What is one characteristic that may indicate pneumonia during a physical examination?

Diminished breath sounds over the affected area Signup and view all the answers

What does a leukocytosis with predominance of polymorphonuclear cells indicate in a patient suspected of pneumonia?

Bacterial infection Signup and view all the answers

Which of the following is a goal of pneumonia management?

Eradication of the offending organism Signup and view all the answers

Which finding on a chest radiograph is indicative of pneumonia?

Dense lobar or segmental infiltrate Signup and view all the answers

What best describes the concept of antimicrobial treatment in pneumonia management?

Providing the right antimicrobial at the right time and dose Signup and view all the answers

What is a potential unintended consequence of antibiotic therapy in pneumonia treatment?

Selection for secondary infections like C. difficile Signup and view all the answers

What symptom may accompany a patient experiencing tachypnea in pneumonia?

Increased tactile fremitus Signup and view all the answers

What is a common laboratory finding in patients with pneumonia?

Hypoxemia on pulse oximetry Signup and view all the answers

Which antibiotic is preferred for treating methicillin-susceptible strains in community-acquired pneumonia?

Cefazolin Signup and view all the answers

What is the treatment of choice for MRSA pneumonia?

Vancomycin Signup and view all the answers

In patients with a hospital-acquired pneumonia prevalence of 20% or greater for MRSA, what coverage should they receive?

MRSA coverage with either vancomycin or linezolid Signup and view all the answers

Which alternative for MRSA pneumonia has limited clinical evidence?

Sulfamethoxazole-trimethoprim Signup and view all the answers

Which antibiotic is recommended for treating penicillin-intermediate strains?

3 g/day of amoxicillin Signup and view all the answers

What should all empiric hospital-acquired pneumonia regimens include?

An antipseudomonal, antistaphylococcal β-lactam Signup and view all the answers

Which pathogen is predominantly responsible for most cases of hospital-acquired pneumonia?

Pseudomonas aeruginosa Signup and view all the answers

What should be included for patients at risk of multidrug-resistant strains of hospital-acquired pneumonia?

MRSA coverage and a second antipseudomonal agent Signup and view all the answers

What characterizes community-acquired pneumonia (CAP)?

Infection occurs outside of the hospital or within 48 hours of admission Signup and view all the answers

Which individuals are most likely to experience impaired lung defenses leading to pneumonia?

Immunocompromised individuals, such as those with cystic fibrosis Signup and view all the answers

How can lung infections lead to further complications?

By suppressing antimicrobacteria activity in the lung Signup and view all the answers

What is a potential consequence of alterations in the normal lung microbiome?

Pneumonia that may require antimicrobial treatment Signup and view all the answers

What role do innate and adaptive immunity pathways play in respiratory defenses?

They are preserved in healthy individuals and remove pathogens before infection occurs Signup and view all the answers

What is the incidence of multidrug resistance in relation to aureus in pneumonia?

It is more common than in community-acquired infections Signup and view all the answers

What can lead to the suppression of antibacterial activity in the lungs?

Lung infections impairing lung function Signup and view all the answers

Which of the following statements about pneumonia is incorrect?

Pneumonia requires antimicrobial treatment in all cases. Signup and view all the answers

Study Notes

CAP and HAP

Community-acquired pneumonia (CAP) occurs outside the hospital or within 48 hours of hospital admission.
Hospital-acquired pneumonia (HAP) occurs 48 hours or more after hospital admission.
Multidrug resistance is more common in HAP.
CAP can be caused by S. pneumoniae, H. influenzae, C. pneumoniae, M. pneumoniae, M. catarrhalis, Enteric Gram-negative bacilli, L. pneumophila, Anaerobes, S. aureus, and P. aeruginosa.
HAP is most commonly caused by gram-negative bacilli, predominantly P. aeruginosa and the Enterobacteriaceae, or S. aureus.

Pathogenesis

Respiratory host defenses are comprised of innate and adaptive immunity pathways.
Healthy individuals have robust defense mechanisms, efficiently removing pathogens before infection.
Immunocompromised individuals lack robust defense mechanisms, increasing susceptibility to infection.
Lung infections can suppress antibacterial activity, impairing alveolar macrophage function and mucociliary clearance, leading to secondary bacterial pneumonia.

### Pathophysiology

Urinary antigen tests detect S. pneumoniae in urine and are more rapid than traditional microbiological methods.

Physical Examination

Tachypnea and tachycardia are common symptoms of pneumonia.
Dullness to percussion, increased tactile fremitus, whisper pectoriloquy, and egophony are signs of pneumonia.
Chest wall retractions and grunting respirations indicate respiratory distress.
Diminished breath sounds over the affected area and inspiratory crackles suggest lung consolidation.

Chest Radiograph

A dense lobar or segmental infiltrate is characteristic of pneumonia.

Laboratory Tests

Leukocytosis with predominance of polymorphonuclear cells, elevated white blood cell count, is a common finding.
Low oxygen saturation on arterial blood gas or pulse oximetry indicates respiratory compromise.

Management of Pneumonia

Treatment goals: Eradication of the offending organism, minimization of unintended consequences of therapy, and minimizing costs.

General Approach to Treatment

Antimicrobial treatment involves selecting the right antibiotic at the right time, dose, and duration.
Continual monitoring of patient clinical status and diagnostic data guides therapy decisions, adjusting or discontinuing treatment as needed.
CURB-65 and CRB-65 are commonly used severity assessment tools for CAP.

CURB-65

The CURB-65 score assigns 1 point for each criterion present:
- Confusion
- Uremia (BUN >20 mg/dL or 7.1 mmol/L)
- Respiratory rate ≥30 breaths/min
- Blood pressure (systolic <90 mmHg or diastolic <60 mmHg)
- Age ≥65 years

### Empiric Therapy for CAP

Low risk of MRSA:
- Ceftriaxone 2 g IV q24h OR Ertapenem 1g IV q24h PLUS Azithromycin 500mg IV daily OR Levofloxacin 750mg IV daily
**Risk of MRSA: **
- Piperacillin-tazobactam 4.5g IV q6h OR Cefepime 2g IV q8-12h OR Meropenem 1g IV q8h PLUS Azithromycin 500mg IV daily PLUS (Gentamicin 5-7mg/kg IV daily OR Amikacin 15mg/kg IV daily) OR (Piperacillin-tazobactam 4.5g IV q6h OR Cefepime 2g IV q8-12h OR Meropenem 1g IV q8h) PLUS (Levofloxacin 750mg IV daily OR Ciprofloxacin 400mg IV q8-12h)
Suspected MRSA pneumonia:
- ADD Vancomycin 25-30mg/kg loading dose then 15-20mg/kg IV q8-12h OR Linezolid 600mg IV q12h

### Duration of Treatment

7-10 days is usually adequate for most pneumonia cases.
28 days is possible for S. aureus or P. aeruginosa with concomitant.

Directed Antimicrobial Therapy for Common Pneumonia Pathogens

S. pneumoniae: The most common bacterial cause of CAP.
- Narrow-spectrum penicillin (penicillin, ampicillin, or amoxicillin) is preferred for susceptible strains (MIC ≤ 2 mg/L).
- Cephalosporin, macrolides, or anti-pneumococcal fluoroquinolones are alternative options.
- Third-generation cephalosporin or fluoroquinolone is preferred for resistant strains.
- High-dose amoxicillin (3 g/day) may be used for intermediate strains (MIC = 4 mg/L).

### Empiric Therapy for HAP

All empiric HAP regimens should cover gram-negative bacilli with at least one antibiotic, typically an antipseudomonal, antistaphylococcal β-lactam or an antipseudomonal, antistaphylococcal fluoroquinolone.
MRSA coverage: If the hospital MRSA prevalence is ≥ 20%, or the patient has risk factors like IV antibiotics in the past 90 days or structural lung disease, vancomycin or linezolid should be added.
MDR gram-negative coverage: Consider adding a second antipseudomonal agent for patients with MDR risk factors.

Directed Therapy for Important Gram-Negative Pathogens

H. influenzae: The most common gram-negative cause of CAP.
- For susceptible strains, oral amoxicillin is commonly used.
- For resistant strains, oral or intravenous cefuroxime, intravenous ceftriaxone, or oral levofloxacin are options.

### Directed Therapy for MRSA Pneumonia

Methicillin-susceptible strains:
- Dicloxacillin is preferred.
- Cefazolin is an alternative option with less clinical data.
- Clindamycin or vancomycin may be used but are not preferred.
Methicillin-resistant strains (MRSA):
- Vancomycin or linezolid are the treatment of choice.
- Alternatives with limited evidence:
  - Quinupristin-dalfopristin
  - Ceftaroline
  - Sulfamethoxazole-trimethoprim
  - Clindamycin

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Description

Explore the key differences between community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP), including their common causes and associated risks. Understand the role of host defenses in the pathogenesis of pneumonia and how they impact infection susceptibility.