Transcript Chapter 22 Pulmonary Infections

Chapter 22
Pulmonary Infections
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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 hospitalacquired pneumonia, health care–acquired
pneumonia, and ventilator-associated
pneumonia.
 Recognize the pathophysiology and common
causes of lower respiratory tract infections in
specific clinical settings.
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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.
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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.
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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.
B.
C.
D.
HAP
HCAP
CAP
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 blood
 Reactivation 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
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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
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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.
B.
C.
D.
Atypical pneumonia
Anaerobic pneumonia
Typical pneumonia
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 pathogen
 Pleural 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




Fever
Purulent sputum
Leukocytosis
New 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.
B.
C.
D.
Use of an endotracheal tube
Foley catheter insertion
Prior antibiotic therapy
Contaminated ventilator equipment
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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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Therapy
 Choice 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 betalactam/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
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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 used
 Isoniazid, rifampin, pyrazinamide, & ethambutol
are first-line antibuberculous medications
 Routine 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 indicated
 Assist with bronchoscopy
 Administer chest physical therapy in selected
cases
 Counsel patients in sputum clearance
techniques such as PEP & autogenic
drainage
 Model optimal infection control practices
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