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Chapter 22 Pulmonary Infections Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973,...
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Transcript of Chapter 22 Pulmonary Infections Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973,...
Chapter 22
Pulmonary Infections
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 2
Learning Objectives
State the incidence of pneumonia in the United States and its economic impact.
Discuss the current classification scheme for pneumonia and be able to define hospital-acquired pneumonia, health care–acquired pneumonia, and ventilator-associated pneumonia.
Recognize the pathophysiology and common causes of lower respiratory tract infections in specific clinical settings.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 3
Learning Objectives (cont.)
List the common microbiological organisms responsible for community acquired and nosocomial pneumonias.
Describe the clinical findings seen in patients with pneumonia.
State the radiographic findings seen in patients with pneumonia; state why some patients with pneumonia may have a normal chest radiograph.
Describe the risk factors associated with increased morbidity and mortality in patients with pneumonia.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 4
Learning Objectives (cont.)
State the criteria used to identify an adequate sputum sample for Gram stain and culture.
Describe the techniques used to identify the organism responsible for a nosocomial pneumonia.
List the latest recommendations regarding the antibiotic regimens used to treat various types of pneumonia, both empiric and pathogen specific.
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 5
Learning Objectives (cont.)
Discuss strategies that can be used to prevent pneumonia.
Describe how the respiratory therapist aids in diagnosis and management of patients with suspected pneumonia.
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Introduction
Infection involving lungs is called “pneumonia” or “lower respiratory tract infection”
Major cause of morbidity & mortality in U.S. & the world
In U.S., about 4 million cases of pneumonia occur each year
Eighth leading cause of death in U.S.
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Classification
Community-acquired pneumonia (CAP) Acute Chronic
Health care–associated pneumonia (HCAP) Pneumonia occurring in any patient hospitalized
for 2 or more days in past 90 days or: Any patient with pneumonia who, in past 30 days,
has resided in a long-term care facility
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Classification (cont.)
Hospital-acquired pneumonia (HAP) Acute lower respiratory tract infection that occurs
in hospitalized patients more than 48 hours after admission
Second most common nosocomial infection
Ventilator-associated pneumonia (VAP) Pneumonia that develops more than 48 to 72
hours after intubation
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Ms. Jones, a 70 year-old female patient has been admitted to the hospital with a diagnosis of acute right lower lobe pneumonia. Her last hospital admission was 120 days before. Her pneumonia should be classified as:
A. HAPB. HCAPC. CAPD. VAP
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Pathogenesis
Inhalation of aerosolized infectious particles Aspiration of organisms Direct inoculation of organisms into lower
airways Spread of infection to lung from adjacent
structures
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Pathogenesis (cont.)
Spread of infection to lung from bloodReactivation of latent infection, usually
resulting from immunosuppression - e.g., Pneumocystis carinii, reactivation tuberculosis, cytomegalovirus
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Ms. Jones was diagnosed with a CAP. Which of the following microorganisms is most likely to have caused Ms. Jones’ pneumonia?
A. M. tuberculosis
B. C. difficile
C. S. aureus
D. S. pneumoniae
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Clinical Manifestations
Patients with CAP typically have fever, cough, sputum production, pleuritic chest pain, & dyspnea
In elderly, pneumonia may not cause fever or cough; it may simply present as dyspnea, confusion, worsening of CHF, or failure to thrive
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 14
Clinical Manifestations (cont.)
VAP traditionally presents with new onset of fever, purulent endotracheal secretions, & new infiltrate
Diagnosis of HAP can be difficult in patient with preexisting pulmonary abnormalities on chest radiograph
Copyright © 2013, 2009, 2003, 1999, 1995, 1990, 1982, 1977, 1973, 1969 by Mosby, an imprint of Elsevier Inc. 15
Ms. Jones, our previous patient, was admitted due to a community acquired pneumonia. She presented with gradual onset of fever, headache, diarrhea, and cough, often with minimal sputum production. Coughing was often a relatively minor symptom at the outset. This pneumonia can be classified as:
A. Atypical pneumoniaB. Anaerobic pneumoniaC. Typical pneumoniaD. Bacterial pneumonia
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Chest Radiograph
Diagnosis of pneumonia is established by presence of new infiltrate on chest film. However: Not all outpatients require chest radiograph Normal chest x-ray does not exclude diagnosis of
pneumonia• Early pneumonia
• Dehydration
• P. jiroveci infection
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Chest Radiograph (cont.)
Consolidation of entire lobe is called “lobar pneumonia”
“Bronchopneumonia” refers to presence of patchy infiltrate surrounding one or more bronchi
Both patterns suggest bacterial pathogenPleural effusions are common in bacterial
pneumonia
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Chest Radiograph (cont.)
Interstitial infiltrates (if diffuse) suggest viral disease, P. jiroveci, or miliary tuberculosis
Cavitary infiltrates (pneumatoceles) are seen in reactivation tuberculosis & some fungal infections
Chest radiograph is less helpful in diagnosis of VAP because patient often has other causes of pulmonary infiltrates
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Clinical Diagnosis of VAP
FeverPurulent sputumLeukocytosisNew pulmonary infiltrates
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Risk Factors for Mortality/Assessing Need for Hospitalization
Many cases of CAP can be treated on outpatient basis
Challenge is to identify those patients at higher risk who need hospitalization
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Risk Factors for Mortality/Assessing Need for Hospitalization (cont.)
Risk of death in pneumonia is increased in: Male patients Hypotension Tachypnea Diabetes Cancer Neurologic disease Bacteremia Leukopenia Multiple lobe involvement
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All of the following are considered risk factors for the development of HAP and VAP, except:
A. Use of an endotracheal tube
B. Foley catheter insertion
C. Prior antibiotic therapy
D. Contaminated ventilator equipment
Diagnostic Studies
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Diagnostic Studies (cont.)
CAP Respiratory therapists play key role in collecting
sputum samples for microbiological examination Satisfactory specimen contains >25 leukocytes
and <10 squamous epithelial cells per hpf Presence of acid-fast bacilli in stain sputum
samples suggests tuberculosis Blood cultures should be obtained in severe cases
of pneumonia
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Diagnostic Studies (cont.)
Nosocomial Pneumonias: HAP, HCAP, VAP Accurate diagnosis
is very difficult
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A positive acid-fast bacilli in stained specimens of sputum is an indication of the presence of which of the following microorganisms?
A. P. jiroveci
B. S. pneumoniae
C. Legionella
D. M. tuberculosis
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TherapyChoice of antibiotic for patient with CAP
depends on: Age of patient Severity of illness Risk factors for specific organisms Results of initial diagnostic tests
For hospitalized patients who are not critically ill: Empirical regimen of advanced macrolide plus
second- or third-generation cephalosporin or beta-lactam/beta-lactamase inhibitor is recommended
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Therapy (cont.)
Therapy should be started within 4 hours of hospital admission
Duration of therapy for CAP is generally for minimum of 5 days
Legionnaires’ disease requires minimum of 2 weeks
Elderly & those with comorbidities may also require longer therapy
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Prevention
Prevention of CAP centers around immunization
Immunization is indicated for individuals: Over age 60 years With chronic lung or heart disease
Prevention (cont.)
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Tuberculosis (TB)
Incidence of TB steadily declined after introduction of effective antibiotics (1950s)
From 1985 to 1992, incidence increased due to emergence of AIDS
Since 1992, incidence of TB has declined again but remains problem for selected groups of patients (e.g., immunocompromised, those living in crowded conditions, those with poor access to health care, etc.)
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Tuberculosis (cont.)
TB is acquired by inhalation of airborne droplets containing M. tuberculosis
Most people exposed to TB do not develop active infection as TB is controlled by an intact immune system
People who are positive for TB but asymptomatic are said to have “latent TB” If they subsequently become debilitated, it may
develop into reactivation TB
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Tuberculosis (cont.)
People who acquire infection upon initial exposure have “primary TB”
Primary TB is most likely to occur in HIV patients
Primary TB causes fevers in 70% of patients, persisting for 14 to 21 days, in most cases
Cough is less common
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Tuberculosis (cont.)
Chest x-ray usually shows lymphadenopathy, while an infiltrate is seen in 25% of cases
In those without HIV infection, reactivation disease accounts for 90% of cases
Most common symptoms in reactivation TB include fever, cough, night sweats, & weight loss
Chest radiograph shows upper lobe infiltrates in 80% to 90% of reactivation TB cases
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Tuberculosis (cont.)
Extrapulmonary TB is defined as spread of organism beyond lung & may involve any organ Most often occurs in CNS, musculoskeletal
system, GI tract, & lymph nodes
History is vitally important in diagnosis of patients with TB Clinician should ask about symptoms, exposure,
travel, prior history of TB, risk factors, etc…
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Tuberculosis (cont.)
Patients diagnosed or suspected of having TB should be placed in respiratory isolation
Gold standard for diagnosis of TB is culture isolation of organism Culture may take 4 to 6 weeks
Acid-fast staining of expectorated sputum may be used in diagnosis
Positive PPD skin test supports diagnosis in appropriate clinical setting
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Tuberculosis (cont.)
Negative skin test may occur in patients with HIV who are infected with TB
Goals of treatment are to cure patient & prevent further transmission
Daily observation therapy should be usedIsoniazid, rifampin, pyrazinamide, & ethambutol
are first-line antibuberculous medicationsRoutine treatment should be given for 6 to 9
months
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Role of Respiratory Therapist in Pulmonary Infections
Collection of sputum samples as indicatedAssist with bronchoscopyAdminister chest physical therapy in selected
casesCounsel patients in sputum clearance
techniques such as PEP & autogenic drainage
Model optimal infection control practices