30
Lower Respiratory Problems
Eugene E. Mondor
http://evolve.elsevier.com/Lewis/medsurg/
CONCEPTUAL FOCUS
Cellular Regulation Gas Exchange
Clotting Infection
Functional Ability
LEARNING OUTCOMES
1. Compare and contrast the clinical manifestations and 7. Compare and contrast the pathophysiology, clinical
nursing and interprofessional management of patients manifestations, and nursing and interprofessional
with acute bronchitis and pertussis. management of fractured ribs, flail chest, and
2. Distinguish among the types of pneumonia and their pneumothorax.
etiology. 8. Describe the pathophysiology, clinical manifestations,
3. Describe the pathophysiology, clinical manifestations, and nursing and interprofessional management of
diagnostic studies, and interprofessional and nursing pulmonary embolism, pulmonary hypertension, and
management of patients with pneumonia. cor pulmonale.
4. Explain the pathophysiology, classification, clinical 9. Identify the causative factors, clinical manifestations, and
manifestations, complications, diagnostic abnormalities, nursing and interprofessional management of patients
and interprofessional and nursing management of patients with environmental lung diseases.
with tuberculosis. 10. State lung disorders in which lung transplantation
5. Describe the pathophysiology, clinical manifestations, and may be a treatment option, explaining the nursing and
nursing and interprofessional management of a patient interprofessional management of the transplant patient.
with a lung abscess. 11. Describe the etiology, risk factors, pathophysiology,
6. Identify the etiology, clinical manifestations, and nursing clinical manifestations, and interprofessional and nursing
and interprofessional management of a patient with a management of the patient with lung cancer.
pleural effusion.
KEY TERMS
acute bronchitis pleurisy (pleuritis)
community-acquired pneumonia (CAP) pneumoconiosis
cor pulmonale pneumonia
empyema pneumothorax
flail chest pulmonary edema
hemothorax pulmonary embolism (PE)
hospital-acquired pneumonia (HAP) pulmonary hypertension
lung abscess tension pneumothorax
pertussis tuberculosis (TB)
pleural effusion
A variety of problems affect the lower respiratory system. This that have the potential to impair gas exchange. Left untreated,
chapter discusses lower respiratory tract diseases that influ- many of these conditions will have profound consequences for
ence gas exchange. We will focus on infectious, restrictive, the patient, as adequate oxygenation and ventilation are both
traumatic, vascular, environmental, and oncologic problems essential for life.
596
, CHAPTER 30 Lower Respiratory Problems 597
LOWER RESPIRATORY TRACT INFECTIONS PERTUSSIS
Lower respiratory tract infection is a common and serious Pertussis is a highly contagious respiratory tract infection. It is
problem. It is the reason for thousands of clinic and emergency caused by the gram-negative bacillus Bordetella pertussis. The
department (ED) visits and hospital admissions each year. In bacteria attach to the cilia of the respiratory tract and release
the United States, pneumonia and influenza cause around toxins that damage the cilia, causing inflammation and swelling.
50,000 deaths each year.1 Cases of pertussis have been steadily increasing in the United
States since the 1980s.2 The largest increase is in teens and
adults. We think that immunity from childhood tetanus, diph-
ACUTE BRONCHITIS theria, and pertussis vaccine (Tdap) vaccination may decrease
Acute bronchitis is a self-limiting inflammation of the bron- over time, allowing a milder (but still contagious) infection to
chi in the lower respiratory tract. It is the reason for 2.7 million occur. The Centers for Disease Control and Prevention (CDC)
outpatient clinic visits and 4 million ED visits per year. Viruses currently recommends that all adolescents (11 years and older)
cause most acute bronchial infections. Air pollution, dust, inha- and adults who have not received a dose of Tdap receive a one-
lation of chemicals, smoking, chronic sinusitis, and asthma are time vaccination as soon as possible.3
other triggers. Manifestations of pertussis occur in stages. The 1st stage,
Cough is the most common symptom. It may last for up lasting 1 to 2 weeks, manifests as a mild upper respiratory
to 3 weeks and is the main reason for seeking medical care. tract infection (URI) with a low-grade or no fever, runny nose,
Coughing is more frequent at night. When present, sputum watery eyes, malaise, and mild, nonproductive cough. The 2nd
is often clear, although some patients have purulent sputum. stage, from the 2nd to 10th weeks of infection, is characterized
Other symptoms may include headache, fever, malaise, hoarse- by paroxysms of cough. The last stage lasts 2 to 3 weeks. The
ness, myalgias, dyspnea, and chest pain. cough is less severe. The patient may still be weak.
Diagnosis is based on the assessment. Assessment may reveal The hallmark characteristic of pertussis is uncontrollable, vio-
normal breath sounds or crackles or wheezes, usually on expira- lent coughing. Inspiration after each cough produces the typical
tion and with exertion. Consolidation (when fluid accumulates “whooping” sound as the patient tries to breathe in air against an
in the lungs), suggestive of pneumonia, is absent with bronchi- obstructed glottis. The “whoop” is often not present in teens and
tis. Chest x-rays are normal and not needed unless we suspect adults (especially those who are vaccinated). Coughing is more fre-
pneumonia or some other lung problem. quent at night. Vomiting may occur with coughing. Unlike acute
The goal of treatment is to relieve symptoms and prevent bronchitis, the cough with pertussis may last from 6 to 10 weeks.
pneumonia. Treatment is supportive. It includes cough suppres- In the community, diagnosis is mainly by history and
sants (e.g., dextromethorphan), encouraging oral fluid intake, assessment. In the acute care setting, the CDC recommends
and using a humidifier. Throat lozenges, hot tea, and honey may nasopharyngeal cultures, polymerase chain reaction (PCR) of
help relieve cough. β2-agonist (bronchodilator) inhalers are use- nasopharyngeal secretions, or serology testing.4 The treatment
ful for patients with wheezes or underlying lung problems. We is macrolide (erythromycin, azithromycin) antibiotics to mini-
do not prescribe antibiotics for viral infections because they are mize symptoms and prevent disease spread (see Table 15.8). For
not effective against viruses and giving them promotes antibi- the patient who cannot take macrolides, trimethoprim/sulfa-
otic resistance. Antibiotics may be given to patients with under- methoxazole is used.
lying chronic conditions who are at risk for or have a prolonged The patient is infectious from the beginning of the 1st stage
infection with systemic symptoms. through the 3rd week after onset of symptoms or until 5 days
Encourage patients to not smoke, avoid secondhand smoke, after starting antibiotic therapy. Place hospitalized patients on
and wash their hands often (Box 30.1). If acute bronchitis is droplet precautions. Patients should not use cough suppressants
due to influenza, we may start treatment with antiviral drugs. and antihistamines as they are ineffective and may cause cough-
If patients with acute bronchitis develop a fever, have trouble ing. Corticosteroids and bronchodilators are also not helpful.
breathing, or have symptoms last longer than 4 weeks, they The CDC recommends antibiotic therapy for those who had
should see their HCP. close contact with the patient.
PNEUMONIA
BOX 30.1 PROMOTING POPULATION
HEALTH Pneumonia is an acute infection of the lung parenchyma.
Preventing Respiratory Diseases Despite progress in antibiotic therapy to treat pneumonia, pneu-
monia still has significant morbidity and mortality. Pneumonia
• ash hands often to prevent and avoid spreading infections.
W and lower respiratory tract infections were the 4th leading cause
• Get a Tdap, pneumococcal, COVID, and flu vaccines as directed by the HCP. of death worldwide in 2019.5
• Avoid smoking and exposure to environmental smoke.
• Wear proper personal protective equipment (PPE) when working in an occu- Etiology
pation with prolonged exposure to dust, fumes, or gases.
Normally, various defense mechanisms protect the airway
• Avoid exposure to allergens, indoor pollutants, and ambient air pollutants.
distal to the larynx from infection. Mechanisms that create a
,598 SECTION 6 Problems of Oxygenation: Ventilation
mechanical barrier to microorganisms entering the tracheo- identify the most likely cause (Table 30.2) and the choice of anti-
bronchial tree include air filtration, epiglottis closure over the microbial therapy.
trachea, cough reflex, mucociliary escalator mechanism, and
reflex bronchoconstriction. Immune defense mechanisms Community-Acquired Pneumonia
include secretion of immunoglobulins A and G and alveolar Community-acquired pneumonia (CAP) is an acute lung
macrophages. infection that occurs in patients who have not been hospitalized
Pneumonia is more likely to occur when defense mecha- or lived in a long-term care facility within 14 days of symptom
nisms become incompetent or are overwhelmed by the vir- onset. The decision to treat the patient at home or admit to a
ulence or quantity of infectious agents. A weakened cough or hospital is based on several factors. These include the patient’s
epiglottal reflex may allow aspiration of oropharyngeal contents age, vital signs, mental status, presence of co-morbid condi-
into the lungs. Tracheal intubation bypasses normal filtration tions, and condition. We can use various tools (Table 30.3) to
processes and interferes with the cough reflex and mucociliary support clinical judgment.
escalator mechanism. Air pollution, smoking, viral URIs, and
normal changes that occur with aging can impair the mucocil- Hospital-Acquired Pneumonia
iary mechanism. Chronic diseases can suppress the immune Hospital-acquired pneumonia (HAP), or nosocomial pneu-
system’s ability to inhibit bacterial growth. Risk factors for monia, is pneumonia in a non-intubated patient that begins 48
pneumonia are listed in Table 30.1. hours or longer after admission to hospital and was not pres-
Pathogens that cause pneumonia reach the lung in 3 ways: ent when they were admitted. Ventilator-associated pneumonia
1. Aspiration of normal flora from the nasopharynx or oro-
pharynx. Many organisms that cause pneumonia are normal
TABLE 30.2 Organisms Causing Pneumonia
inhabitants of the mouth and pharynx in healthy adults.
2. Inhalation of microbes present in the air. Examples include Community-Acquired Pneumonia (CAP)
Typical
Mycoplasma pneumoniae and fungal pneumonias.
• Escherichia coli
3. Hematogenous spread from a primary infection elsewhere in
• Haemophilus influenzaea
the body. One example is Staphylococcus aureus from infec- • Klebsiella pneumoniaea
tive endocarditis. • Methicillin resistant staphylococcus aureus (MRSA)
• Moraxella catarrhalis
Classifications of Pneumonia • Pseudomonas
There is no universally accepted classification system for pneu- • Staphylococcus aureusa
monia. Some classify pneumonia by the causative pathogens • Streptococcus pneumoniaea
(e.g., bacterial, viral, fungal), disease characteristics, or appear-
Atypical
ance on chest x-ray. The most widely recognized and effective
• Chlamydophila pneumoniae
way to classify pneumonia is as either community-acquired or
• Coxiella burnettii
hospital-acquired pneumonia. This classification helps the HCP • Influenza A and B
• Legionella pneumophilia
• Mycoplasma pneumoniae
TABLE 30.1 Risk Factors for Pneumonia • Mycobacterium tuberculosis
• Abdominal or chest surgery
Respiratory Viruses
• Age >65 years
• Parainfluenza virus
• Air pollution
• Respiratory syncytial virus
• Altered level of consciousness (e.g., head injury, seizures, anesthesia,
• Rhinovirus
drug overdose, stroke)
• Bed rest and prolonged immobility Other Causes of CAP
• Chronic diseases: chronic lung and liver disease, diabetes, heart disease, • Fungi
cancer, chronic kidney disease • Oral anaerobes
• Debilitating illness
• Enteral feedings via naso- or orogastric or intestinal tubes Hospital-Acquired Pneumonia (HAP)
• Exposure to bats, birds, rabbits, and farm animal feces • Escherichia colib
• Immunosuppressive conditions and/or therapy (e.g., corticosteroids, can- • Haemophilus influenzae
cer chemotherapy, HIV infection, immunosuppressive therapy after organ • Klebsiella pneumoniaeb
transplant) • Microaspiration of bacteria that colonize the mouth, oropharynx
• Inhalation or aspiration of noxious substances • Pseudomonas aeruginosab
• IV drug use • Proteus species
• Malnutrition • Serratia marcescens
• Resident of a long-term care facility • Staphylococcus aureus
• Smoking • Streptococcus pneumoniaea
• Tracheal intubation (endotracheal intubation, tracheostomy) aMost common cause of CAP.
• URI bMost common causes of HAP.
, CHAPTER 30 Lower Respiratory Problems 599
TABLE 30.3 Pneumonia Severity Index (PSI) pneumonia, which has traits of both bacteria and viruses, is
often called “atypical” pneumonia. It is mild and occurs in per-
The PSI can supplement clinical judgment to determine the severity of
sons younger than 40 years of age.
pneumonia and if patients need to be hospitalized.
Factor Points Aspiration Pneumonia
Demographics
Aspiration pneumonia results from the abnormal entry of
Age in years material from the mouth or stomach into the trachea and
Women – 10 lungs. Conditions that increase the risk for aspiration include
Extended care resident +10 decreased level of consciousness (e.g., seizure, anesthesia, head
injury, stroke, alcohol use), swallowing problems, and having
Other Conditions a nasogastric (NG) tube with or without enteral feeding. With
Stroke, kidney disease, heart failure +10 each loss of consciousness, the gag and cough reflexes are depressed,
Active cancer +30
making aspiration more likely.
Liver disease +20
The aspirated material (food, water, vomitus, oropharyngeal
Assessment secretions) triggers an inflammatory response. The most com-
Respiratory rate ≥30/min, BP < 90, altered mon form of aspiration pneumonia is a primary bacterial infec-
mental status +20 each tion. Typically, the sputum culture shows more than 1 organism,
Pulse 125/min +10 including aerobes and anaerobes, since they both make up the
Temperature <95°F (35°C) or ≥104°F (4O°C) +15 flora of the oropharynx.
Pleural effusion +10 Until cultures are done and results obtained, initial antibiotic
Laboratory Results
therapy is based on an assessment of probable cause, severity
pH < 7.35 +30 of illness, and patient factors (e.g., malnutrition, current use
BUN ≥30 mg/dL, Sodium <130 mEq/L +20 each of antibiotic therapy). For patients who aspirate in hospitals,
Glucose 250 mg/dL, Hematocrit < 30%, +10 each antibiotic coverage should include both gram-negative organ-
pAO2 <60 mm Hg or O2 <90 percent isms and methicillin-resistant Staphylococcus aureus (MRSA).
Scoring: Aspiration of acidic gastric contents can cause chemical (non-
<70 points Outpatient infectious) pneumonitis, which may not need antibiotic ther-
71-90 points Outpatient vs. apy. However, secondary bacterial infection can occur in these
Observation patients 48 to 72 hours later.
>91 points Inpatient
Necrotizing Pneumonia
Source: Community-acquired pneumonia severity index (PSI) for
adults. Retrieved from https://www.clinicalkey.com/#!/tools/calcula- Necrotizing pneumonia is a rare complication of bacterial lung
tors/calculator/77-s2.0-99. infection. It causes the lung tissue to turn into a thick, liquid
mass. Cavitation and lung abscesses can occur. This sometimes
(VAP), a type of HAP, refers to pneumonia that occurs more happens with CAP. We do not know the exact mechanisms
than 48 hours after endotracheal intubation.6 VAP is discussed involved. Common causative organisms include Staphylococcus,
in Chapter 28. Both HAP and VAP are associated with longer Klebsiella, and Streptococcus. Signs and symptoms include respi-
hospital stays, increased associated costs, sicker patients, and ratory insufficiency and/or failure, leukocytosis, and abnormal-
increased mortality. ities on chest imaging.7 Treatment includes long-term antibiotic
Once the diagnosis of CAP, HAP, or VAP is made, treatment therapy and possible surgery.
is started based on risk factors, speed of onset, clinical presen-
tation, underlying medical conditions, hemodynamic stability, Opportunistic Pneumonia
and the most likely causative pathogen. Empiric antibiotic ther- Opportunistic pneumonia is inflammation and infection of
apy, the initiation of treatment before a definitive diagnosis or the lower respiratory tract in immunocompromised patients.
causative agent is made, should be started as soon as pneumonia Persons at risk include those with altered immune responses.
is suspected. Empiric antibiotic therapy is based on the drugs This can include people with severe protein-calorie malnutri-
known to be effective for the most likely cause. Antibiotic ther- tion or immunodeficiencies (e.g., human immunodeficiency
apy is adjusted once the results of sputum cultures identify the virus [HIV] infection) and those receiving radiation therapy,
exact pathogen causing the infection. chemotherapy, and any immunosuppressive therapy, including
long-term corticosteroid therapy. In addition to the risk for bac-
Types of Pneumonia terial and viral pneumonia, the immunocompromised person
There are several types of pneumonia. Viral pneumonia is the may develop an infection from organisms that do not normally
most common type. It occurs in one third of all pneumonia cause disease, such as Pneumocystis jiroveci pneumonia (PJP) or
cases. It may be mild and self-limiting or cause potentially cytomegalovirus (CMV).8
life-threatening problems, such as acute respiratory failure PJP is occurring with greater frequency in HIV-negative,
(ARF) in influenza. Patients with bacterial pneumonia may be immunocompromised persons.8 The onset is slow and sub-
extremely unwell and need hospital admission. Mycoplasma tle. Symptoms include fever, tachypnea, tachycardia, dyspnea,
Lower Respiratory Problems
Eugene E. Mondor
http://evolve.elsevier.com/Lewis/medsurg/
CONCEPTUAL FOCUS
Cellular Regulation Gas Exchange
Clotting Infection
Functional Ability
LEARNING OUTCOMES
1. Compare and contrast the clinical manifestations and 7. Compare and contrast the pathophysiology, clinical
nursing and interprofessional management of patients manifestations, and nursing and interprofessional
with acute bronchitis and pertussis. management of fractured ribs, flail chest, and
2. Distinguish among the types of pneumonia and their pneumothorax.
etiology. 8. Describe the pathophysiology, clinical manifestations,
3. Describe the pathophysiology, clinical manifestations, and nursing and interprofessional management of
diagnostic studies, and interprofessional and nursing pulmonary embolism, pulmonary hypertension, and
management of patients with pneumonia. cor pulmonale.
4. Explain the pathophysiology, classification, clinical 9. Identify the causative factors, clinical manifestations, and
manifestations, complications, diagnostic abnormalities, nursing and interprofessional management of patients
and interprofessional and nursing management of patients with environmental lung diseases.
with tuberculosis. 10. State lung disorders in which lung transplantation
5. Describe the pathophysiology, clinical manifestations, and may be a treatment option, explaining the nursing and
nursing and interprofessional management of a patient interprofessional management of the transplant patient.
with a lung abscess. 11. Describe the etiology, risk factors, pathophysiology,
6. Identify the etiology, clinical manifestations, and nursing clinical manifestations, and interprofessional and nursing
and interprofessional management of a patient with a management of the patient with lung cancer.
pleural effusion.
KEY TERMS
acute bronchitis pleurisy (pleuritis)
community-acquired pneumonia (CAP) pneumoconiosis
cor pulmonale pneumonia
empyema pneumothorax
flail chest pulmonary edema
hemothorax pulmonary embolism (PE)
hospital-acquired pneumonia (HAP) pulmonary hypertension
lung abscess tension pneumothorax
pertussis tuberculosis (TB)
pleural effusion
A variety of problems affect the lower respiratory system. This that have the potential to impair gas exchange. Left untreated,
chapter discusses lower respiratory tract diseases that influ- many of these conditions will have profound consequences for
ence gas exchange. We will focus on infectious, restrictive, the patient, as adequate oxygenation and ventilation are both
traumatic, vascular, environmental, and oncologic problems essential for life.
596
, CHAPTER 30 Lower Respiratory Problems 597
LOWER RESPIRATORY TRACT INFECTIONS PERTUSSIS
Lower respiratory tract infection is a common and serious Pertussis is a highly contagious respiratory tract infection. It is
problem. It is the reason for thousands of clinic and emergency caused by the gram-negative bacillus Bordetella pertussis. The
department (ED) visits and hospital admissions each year. In bacteria attach to the cilia of the respiratory tract and release
the United States, pneumonia and influenza cause around toxins that damage the cilia, causing inflammation and swelling.
50,000 deaths each year.1 Cases of pertussis have been steadily increasing in the United
States since the 1980s.2 The largest increase is in teens and
adults. We think that immunity from childhood tetanus, diph-
ACUTE BRONCHITIS theria, and pertussis vaccine (Tdap) vaccination may decrease
Acute bronchitis is a self-limiting inflammation of the bron- over time, allowing a milder (but still contagious) infection to
chi in the lower respiratory tract. It is the reason for 2.7 million occur. The Centers for Disease Control and Prevention (CDC)
outpatient clinic visits and 4 million ED visits per year. Viruses currently recommends that all adolescents (11 years and older)
cause most acute bronchial infections. Air pollution, dust, inha- and adults who have not received a dose of Tdap receive a one-
lation of chemicals, smoking, chronic sinusitis, and asthma are time vaccination as soon as possible.3
other triggers. Manifestations of pertussis occur in stages. The 1st stage,
Cough is the most common symptom. It may last for up lasting 1 to 2 weeks, manifests as a mild upper respiratory
to 3 weeks and is the main reason for seeking medical care. tract infection (URI) with a low-grade or no fever, runny nose,
Coughing is more frequent at night. When present, sputum watery eyes, malaise, and mild, nonproductive cough. The 2nd
is often clear, although some patients have purulent sputum. stage, from the 2nd to 10th weeks of infection, is characterized
Other symptoms may include headache, fever, malaise, hoarse- by paroxysms of cough. The last stage lasts 2 to 3 weeks. The
ness, myalgias, dyspnea, and chest pain. cough is less severe. The patient may still be weak.
Diagnosis is based on the assessment. Assessment may reveal The hallmark characteristic of pertussis is uncontrollable, vio-
normal breath sounds or crackles or wheezes, usually on expira- lent coughing. Inspiration after each cough produces the typical
tion and with exertion. Consolidation (when fluid accumulates “whooping” sound as the patient tries to breathe in air against an
in the lungs), suggestive of pneumonia, is absent with bronchi- obstructed glottis. The “whoop” is often not present in teens and
tis. Chest x-rays are normal and not needed unless we suspect adults (especially those who are vaccinated). Coughing is more fre-
pneumonia or some other lung problem. quent at night. Vomiting may occur with coughing. Unlike acute
The goal of treatment is to relieve symptoms and prevent bronchitis, the cough with pertussis may last from 6 to 10 weeks.
pneumonia. Treatment is supportive. It includes cough suppres- In the community, diagnosis is mainly by history and
sants (e.g., dextromethorphan), encouraging oral fluid intake, assessment. In the acute care setting, the CDC recommends
and using a humidifier. Throat lozenges, hot tea, and honey may nasopharyngeal cultures, polymerase chain reaction (PCR) of
help relieve cough. β2-agonist (bronchodilator) inhalers are use- nasopharyngeal secretions, or serology testing.4 The treatment
ful for patients with wheezes or underlying lung problems. We is macrolide (erythromycin, azithromycin) antibiotics to mini-
do not prescribe antibiotics for viral infections because they are mize symptoms and prevent disease spread (see Table 15.8). For
not effective against viruses and giving them promotes antibi- the patient who cannot take macrolides, trimethoprim/sulfa-
otic resistance. Antibiotics may be given to patients with under- methoxazole is used.
lying chronic conditions who are at risk for or have a prolonged The patient is infectious from the beginning of the 1st stage
infection with systemic symptoms. through the 3rd week after onset of symptoms or until 5 days
Encourage patients to not smoke, avoid secondhand smoke, after starting antibiotic therapy. Place hospitalized patients on
and wash their hands often (Box 30.1). If acute bronchitis is droplet precautions. Patients should not use cough suppressants
due to influenza, we may start treatment with antiviral drugs. and antihistamines as they are ineffective and may cause cough-
If patients with acute bronchitis develop a fever, have trouble ing. Corticosteroids and bronchodilators are also not helpful.
breathing, or have symptoms last longer than 4 weeks, they The CDC recommends antibiotic therapy for those who had
should see their HCP. close contact with the patient.
PNEUMONIA
BOX 30.1 PROMOTING POPULATION
HEALTH Pneumonia is an acute infection of the lung parenchyma.
Preventing Respiratory Diseases Despite progress in antibiotic therapy to treat pneumonia, pneu-
monia still has significant morbidity and mortality. Pneumonia
• ash hands often to prevent and avoid spreading infections.
W and lower respiratory tract infections were the 4th leading cause
• Get a Tdap, pneumococcal, COVID, and flu vaccines as directed by the HCP. of death worldwide in 2019.5
• Avoid smoking and exposure to environmental smoke.
• Wear proper personal protective equipment (PPE) when working in an occu- Etiology
pation with prolonged exposure to dust, fumes, or gases.
Normally, various defense mechanisms protect the airway
• Avoid exposure to allergens, indoor pollutants, and ambient air pollutants.
distal to the larynx from infection. Mechanisms that create a
,598 SECTION 6 Problems of Oxygenation: Ventilation
mechanical barrier to microorganisms entering the tracheo- identify the most likely cause (Table 30.2) and the choice of anti-
bronchial tree include air filtration, epiglottis closure over the microbial therapy.
trachea, cough reflex, mucociliary escalator mechanism, and
reflex bronchoconstriction. Immune defense mechanisms Community-Acquired Pneumonia
include secretion of immunoglobulins A and G and alveolar Community-acquired pneumonia (CAP) is an acute lung
macrophages. infection that occurs in patients who have not been hospitalized
Pneumonia is more likely to occur when defense mecha- or lived in a long-term care facility within 14 days of symptom
nisms become incompetent or are overwhelmed by the vir- onset. The decision to treat the patient at home or admit to a
ulence or quantity of infectious agents. A weakened cough or hospital is based on several factors. These include the patient’s
epiglottal reflex may allow aspiration of oropharyngeal contents age, vital signs, mental status, presence of co-morbid condi-
into the lungs. Tracheal intubation bypasses normal filtration tions, and condition. We can use various tools (Table 30.3) to
processes and interferes with the cough reflex and mucociliary support clinical judgment.
escalator mechanism. Air pollution, smoking, viral URIs, and
normal changes that occur with aging can impair the mucocil- Hospital-Acquired Pneumonia
iary mechanism. Chronic diseases can suppress the immune Hospital-acquired pneumonia (HAP), or nosocomial pneu-
system’s ability to inhibit bacterial growth. Risk factors for monia, is pneumonia in a non-intubated patient that begins 48
pneumonia are listed in Table 30.1. hours or longer after admission to hospital and was not pres-
Pathogens that cause pneumonia reach the lung in 3 ways: ent when they were admitted. Ventilator-associated pneumonia
1. Aspiration of normal flora from the nasopharynx or oro-
pharynx. Many organisms that cause pneumonia are normal
TABLE 30.2 Organisms Causing Pneumonia
inhabitants of the mouth and pharynx in healthy adults.
2. Inhalation of microbes present in the air. Examples include Community-Acquired Pneumonia (CAP)
Typical
Mycoplasma pneumoniae and fungal pneumonias.
• Escherichia coli
3. Hematogenous spread from a primary infection elsewhere in
• Haemophilus influenzaea
the body. One example is Staphylococcus aureus from infec- • Klebsiella pneumoniaea
tive endocarditis. • Methicillin resistant staphylococcus aureus (MRSA)
• Moraxella catarrhalis
Classifications of Pneumonia • Pseudomonas
There is no universally accepted classification system for pneu- • Staphylococcus aureusa
monia. Some classify pneumonia by the causative pathogens • Streptococcus pneumoniaea
(e.g., bacterial, viral, fungal), disease characteristics, or appear-
Atypical
ance on chest x-ray. The most widely recognized and effective
• Chlamydophila pneumoniae
way to classify pneumonia is as either community-acquired or
• Coxiella burnettii
hospital-acquired pneumonia. This classification helps the HCP • Influenza A and B
• Legionella pneumophilia
• Mycoplasma pneumoniae
TABLE 30.1 Risk Factors for Pneumonia • Mycobacterium tuberculosis
• Abdominal or chest surgery
Respiratory Viruses
• Age >65 years
• Parainfluenza virus
• Air pollution
• Respiratory syncytial virus
• Altered level of consciousness (e.g., head injury, seizures, anesthesia,
• Rhinovirus
drug overdose, stroke)
• Bed rest and prolonged immobility Other Causes of CAP
• Chronic diseases: chronic lung and liver disease, diabetes, heart disease, • Fungi
cancer, chronic kidney disease • Oral anaerobes
• Debilitating illness
• Enteral feedings via naso- or orogastric or intestinal tubes Hospital-Acquired Pneumonia (HAP)
• Exposure to bats, birds, rabbits, and farm animal feces • Escherichia colib
• Immunosuppressive conditions and/or therapy (e.g., corticosteroids, can- • Haemophilus influenzae
cer chemotherapy, HIV infection, immunosuppressive therapy after organ • Klebsiella pneumoniaeb
transplant) • Microaspiration of bacteria that colonize the mouth, oropharynx
• Inhalation or aspiration of noxious substances • Pseudomonas aeruginosab
• IV drug use • Proteus species
• Malnutrition • Serratia marcescens
• Resident of a long-term care facility • Staphylococcus aureus
• Smoking • Streptococcus pneumoniaea
• Tracheal intubation (endotracheal intubation, tracheostomy) aMost common cause of CAP.
• URI bMost common causes of HAP.
, CHAPTER 30 Lower Respiratory Problems 599
TABLE 30.3 Pneumonia Severity Index (PSI) pneumonia, which has traits of both bacteria and viruses, is
often called “atypical” pneumonia. It is mild and occurs in per-
The PSI can supplement clinical judgment to determine the severity of
sons younger than 40 years of age.
pneumonia and if patients need to be hospitalized.
Factor Points Aspiration Pneumonia
Demographics
Aspiration pneumonia results from the abnormal entry of
Age in years material from the mouth or stomach into the trachea and
Women – 10 lungs. Conditions that increase the risk for aspiration include
Extended care resident +10 decreased level of consciousness (e.g., seizure, anesthesia, head
injury, stroke, alcohol use), swallowing problems, and having
Other Conditions a nasogastric (NG) tube with or without enteral feeding. With
Stroke, kidney disease, heart failure +10 each loss of consciousness, the gag and cough reflexes are depressed,
Active cancer +30
making aspiration more likely.
Liver disease +20
The aspirated material (food, water, vomitus, oropharyngeal
Assessment secretions) triggers an inflammatory response. The most com-
Respiratory rate ≥30/min, BP < 90, altered mon form of aspiration pneumonia is a primary bacterial infec-
mental status +20 each tion. Typically, the sputum culture shows more than 1 organism,
Pulse 125/min +10 including aerobes and anaerobes, since they both make up the
Temperature <95°F (35°C) or ≥104°F (4O°C) +15 flora of the oropharynx.
Pleural effusion +10 Until cultures are done and results obtained, initial antibiotic
Laboratory Results
therapy is based on an assessment of probable cause, severity
pH < 7.35 +30 of illness, and patient factors (e.g., malnutrition, current use
BUN ≥30 mg/dL, Sodium <130 mEq/L +20 each of antibiotic therapy). For patients who aspirate in hospitals,
Glucose 250 mg/dL, Hematocrit < 30%, +10 each antibiotic coverage should include both gram-negative organ-
pAO2 <60 mm Hg or O2 <90 percent isms and methicillin-resistant Staphylococcus aureus (MRSA).
Scoring: Aspiration of acidic gastric contents can cause chemical (non-
<70 points Outpatient infectious) pneumonitis, which may not need antibiotic ther-
71-90 points Outpatient vs. apy. However, secondary bacterial infection can occur in these
Observation patients 48 to 72 hours later.
>91 points Inpatient
Necrotizing Pneumonia
Source: Community-acquired pneumonia severity index (PSI) for
adults. Retrieved from https://www.clinicalkey.com/#!/tools/calcula- Necrotizing pneumonia is a rare complication of bacterial lung
tors/calculator/77-s2.0-99. infection. It causes the lung tissue to turn into a thick, liquid
mass. Cavitation and lung abscesses can occur. This sometimes
(VAP), a type of HAP, refers to pneumonia that occurs more happens with CAP. We do not know the exact mechanisms
than 48 hours after endotracheal intubation.6 VAP is discussed involved. Common causative organisms include Staphylococcus,
in Chapter 28. Both HAP and VAP are associated with longer Klebsiella, and Streptococcus. Signs and symptoms include respi-
hospital stays, increased associated costs, sicker patients, and ratory insufficiency and/or failure, leukocytosis, and abnormal-
increased mortality. ities on chest imaging.7 Treatment includes long-term antibiotic
Once the diagnosis of CAP, HAP, or VAP is made, treatment therapy and possible surgery.
is started based on risk factors, speed of onset, clinical presen-
tation, underlying medical conditions, hemodynamic stability, Opportunistic Pneumonia
and the most likely causative pathogen. Empiric antibiotic ther- Opportunistic pneumonia is inflammation and infection of
apy, the initiation of treatment before a definitive diagnosis or the lower respiratory tract in immunocompromised patients.
causative agent is made, should be started as soon as pneumonia Persons at risk include those with altered immune responses.
is suspected. Empiric antibiotic therapy is based on the drugs This can include people with severe protein-calorie malnutri-
known to be effective for the most likely cause. Antibiotic ther- tion or immunodeficiencies (e.g., human immunodeficiency
apy is adjusted once the results of sputum cultures identify the virus [HIV] infection) and those receiving radiation therapy,
exact pathogen causing the infection. chemotherapy, and any immunosuppressive therapy, including
long-term corticosteroid therapy. In addition to the risk for bac-
Types of Pneumonia terial and viral pneumonia, the immunocompromised person
There are several types of pneumonia. Viral pneumonia is the may develop an infection from organisms that do not normally
most common type. It occurs in one third of all pneumonia cause disease, such as Pneumocystis jiroveci pneumonia (PJP) or
cases. It may be mild and self-limiting or cause potentially cytomegalovirus (CMV).8
life-threatening problems, such as acute respiratory failure PJP is occurring with greater frequency in HIV-negative,
(ARF) in influenza. Patients with bacterial pneumonia may be immunocompromised persons.8 The onset is slow and sub-
extremely unwell and need hospital admission. Mycoplasma tle. Symptoms include fever, tachypnea, tachycardia, dyspnea,
