UPDATE IN OFFICE MANAGEMENT
Treatment of Community-Acquired Pneumonia in an
Ambulatory Setting
Saira Butt, MD,a Edwin Swiatlo, MD, PhDa,b
a
Department of Medicine, Division of Infectious Diseases, University of Mississippi Medical Center, Jackson; bVA Medical Center,
Jackson, Miss.
ABSTRACT
Community-acquired pneumonia continues to be a significant cause of morbidity and mortality despite
broad-spectrum antibiotics and advances in critical care. Frequently, the diagnosis is confounded by
coexisting cardiac or pulmonary conditions. Recognition of patients at risk for complications from
pneumonia is critical when making the decision of how and where to treat. This review summarizes the
diagnosis and treatment of community-acquired pneumonia with oral antibiotics in an outpatient setting.
Specific pathogens and clinical presentations in certain at-risk populations are highlighted. Also presented
are validated algorithms for evaluating and identifying patients who may be at risk for serious complications of pneumonia and require treatment in an inpatient setting.
Published by Elsevier Inc. • The American Journal of Medicine (2011) 124, 297-300
KEYWORDS: Antibiotics; Pneumonia; Vaccines
Community-acquired pneumonia is diagnosed in 3 to 4
million persons annually and continues to be a leading cause
of death in the United States. One study estimated that more
than 900,000 cases of community-acquired pneumonia occur each year in persons aged more than 65 years.1 Approximately 80% of patients with pneumonia are treated as
outpatients. Common risk factors for community-acquired
pneumonia include age greater than 65 years, smoking,
alcohol consumption, chronic lung diseases, mechanical obstruction of airways, aspiration of oropharyngeal or gastric
contents, pulmonary edema, uremia, and malnutrition.2
CLINICAL PRESENTATION
Typical bacterial pathogens such as Streptococcus pneumoniae (pneumococcus), Haemophilus influenzae, and enteric gram-negative organisms usually manifest acutely with
high fever, chills, tachypnea, tachycardia, and productive
Funding: Department of Medicine, University of Mississippi Medical
Center and Department of Veterans Affairs.
Conflict of Interest: None.
Authorship: All authors had access to the data and played a role in
writing this manuscript.
Reprint requests should be addressed to Edwin Swiatlo, MD, PhD, VA
Medical Center Research (151), 1500 Woodrow Wilson Drive, Jackson,
MS 39216.
E-mail address: Edwin.swiatlo@va.gov.
0002-9343/$ -see front matter Published by Elsevier Inc.
doi:10.1016/j.amjmed.2010.06.027
cough. In contrast, “atypical” pathogens such as Mycoplasma, Chlamydophila, and viruses often present with fever, nonproductive cough, and constitutional symptoms that
develop over days. Legionella initially may produce primarily gastrointestinal symptoms. A careful history, including
travel, animal exposure, incarceration, asplenia, human immunodeficiency virus, and other comorbidities, can often
suggest an otherwise unsuspected pathogen.
Systemic physical findings in pneumonia are nonspecific
and include fever/chills, fatigue, myalgias, or headaches.
Pulmonary findings in pneumonia are typically localized to
a specific lung zone and may include rales, rhonchi, bronchial breath sounds, dullness, increased fremitus, and egophony. Atypical pneumonia may have absent or diffuse
findings on lung examination. Rapid progression of disease
from mild, nonspecific symptoms to respiratory failure can
be seen in severe pneumococcal, staphylococcal, or Legionella pneumonia.3,4
The age of the patient has important implications in
disease presentation. Older patients often have humoral or
cellular immunodeficiencies as a result of underlying diseases, immunosuppressive medications, or the aging process. Older patients with pneumonia have fewer symptoms
than do younger patients, and mental status changes are
commonly the predominant presenting symptom. Delirium
may be the only manifestation of pneumonia in these pa-
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tients. Alcoholism, asthma, immunosuppression, and
age ⬎ 70 years are risk factors for community-acquired
pneumonia in the elderly. Among nursing home residents,
advanced age, male sex, dysphagia, inability to take oral
medications, profound disability, bedridden state, and urinary incontinence are risk factors for community-acquired
pneumonia. Aspiration pneumonia is underdiagnosed in this
group of patients, and tuberculosis always should be
considered.5
Extrapulmonary physical findings can provide clues to
the diagnosis. Poor dentition and foul-smelling sputum may
indicate the presence of a lung abscess with anaerobic
bacteria. Bullous myringitis can accompany infection with
Mycoplasma pneumoniae. An absent gag reflex or altered
sensorium raises the possibility of aspiration and polymicrobial infection with anaerobes. Encephalitis can complicate pneumonia caused by M. pneumoniae or Legionella
pneumophila. Cutaneous manifestations of infection can
include erythema multiforme (especially M. pneumoniae),
erythema nodosum (Chlamydophila pneumoniae or Mycobacterium tuberculosis), or ecthyma gangrenosum (Pseudomonas aeruginosa).
LABORATORY DATA
Diagnostic tests such as sputum and blood cultures are
optional for an etiologic diagnosis in outpatients with community-acquired pneumonia. Nasopharyngeal swabs should
be collected for influenza during the appropriate season or
when influenza is circulating in the community. Patients
with cough for more than 1 month, chronic fever, night
sweats, weight loss, or a suggestive chest X-ray should be
evaluated for M. tuberculosis. A high level of suspicion is
necessary to diagnose infections caused by agents of
bioterrorism.6
RADIOGRAPHY
The cornerstone of diagnosis is the chest X-ray, which
usually reveals an infiltrate at presentation. However, this
finding may be absent in dehydrated or neutropenic patients.
Also, the radiographic manifestations of chronic diseases
such as congestive heart failure, chronic obstructive pulmonary disease, and malignancy may obscure the infiltrate of
pneumonia.7 Although radiographic patterns are usually
nonspecific, they can sometimes suggest a microbiological
diagnosis. Focal consolidation is seen in typical bacterial
pneumonia, whereas viruses, Mycoplasma, and Chlamydophila frequently present with an interstitial pattern. Cavitary
lesions may be associated with bacterial abscesses, fungi, or
Nocardia. Rapid progression with multifocal lung involvement may indicate Legionella, S. pneumoniae, or Staphylococcus aureus.8
MANAGEMENT
Choosing the site of care for community-acquired pneumonia is the single most important decision made by clinicians.
The American Journal of Medicine, Vol 124, No 4, April 2011
Table 1
Pneumonia Severity Index
Points
Demographic factors
Age for men
Age for women
Nursing home resident
Coexisting illnesses
Active neoplastic disease
Chronic liver disease
CHF
Cerebrovascular disease
Chronic renal disease
Physical examination
Altered mental status
Respiratory rate ⬎ 30
Blood pressure ⬍ 90 mm Hg
Temperature ⬍ 35°C or ⱖ 40°C
Pulse ⱖ 125 bpm
Laboratory and radiographic findings
Arterial pH ⬍ 7.35
BUN ⱖ 30 mg/dL
Sodium ⬍ 130 mmol/L
Glucose ⱖ 250 mg/dL
Hematocrit ⬍ 30%
PaO2 ⬍ 60 mm Hg
Pleural effusion
CHF ⫽ congestive heart failure; BUN ⫽ blood
PaO2 ⫽ partial pressure of arterial oxygen.
Age (y)
Age (y) ⫺10
⫹10
⫹30
⫹20
⫹10
⫹10
⫹10
⫹20
⫹20
⫹20
⫹15
⫹10
⫹30
⫹20
⫹20
⫹10
⫹10
⫹10
⫹10
urea
nitrogen;
This decision involves 3 steps: determination of disease
severity, assessment of any preexisting social conditions
that compromise the safety of home care, and clinical judgment. The Pneumonia Severity Index assesses 20 variables
(Table 1) and places patients into 5 risk groups that can help
to stratify patients for therapeutic and prognostic purposes.9
Patients in groups I and II can be treated as outpatients,
patients in group III can be treated with a short hospitalization or in observational units, and patients in groups IV and
V should be treated as inpatients.
A more tractable model for community-acquired pneumonia severity assessment is CURB-65.9 The CURB-65
score is based on 5 easily measurable factors (1 point for
each) from which its name is derived: confusion (based on
a specific mental test or new disorientation to person, place,
or time); blood urea nitrogen ⬎ 20 mg/dL; respiratory
rate ⬎ 30 breaths/min; blood pressure (systolic ⬍ 90 mm Hg
or diastolic ⬍ 60 mm Hg); and age ⬎ 65 years. Patients with
a CURB-65 score of 0 to 1 can generally be treated as
outpatients, those with a score of 2 should be admitted to
the hospital, and those with a score of 3 or more are
candidates for an intensive care unit.10 In addition to
medical criteria, residential status also influences treatment decisions. Residents of chronic care facilities,
homeless persons, and incarcerated persons are more
likely to be admitted than other patients with similar
severity scores. Outpatient therapy is preferred because
Butt and Swiatlo
Community-acquired Pneumonia
Table 2 Recommended Empirical Antibiotics for Outpatient
Therapy of Community-Acquired Pneumonia1
Previously healthy, no recent (within 3 mo) antibiotic therapy:
macrolide OR doxycycline
Previously healthy, antibiotics within past 3 mo:
azithromycin or clarithromycin, PLUS high-dose amoxicillin
(4 g/d) or amoxicillin-clavulanate (4 g/d); OR a respiratory
fluoroquinolone alone
Comorbidities (COPD, diabetes, renal or congestive heart failure,
malignancy), no recent antibiotic therapy:
azithromycin or clarithromycin; OR a respiratory
fluoroquinolone alone
Comorbidities, antibiotics within past 3 mo:
azithromycin or clarithromycin, PLUS high-dose amoxicillin,
amoxicillin/clavulanate, cefpodoxime, cefprozil, or
cefuroxime; OR a respiratory fluoroquinolone
COPD ⫽ chronic obstructive pulmonary disease.
this is associated with faster return to normal activities
than inpatient treatment.10
ANTIBIOTICS
Antimicrobial therapy is a critical component of treatment
of community-acquired pneumonia in the outpatient setting.
Until better diagnostic tests are available, initial treatment
remains largely empiric. Antibiotics recommended on the
basis of risk factors and likely pathogens have been published recently and are summarized in Table 2.1 Presently,
macrolides remain effective for patients with mild to moderately severe community-acquired pneumonia with no risk
factors.
Patients with chronic obstructive lung disease who
have not received antibiotics or oral steroids during the
previous 3 months can be treated in a manner identical to
that of patients without modifying factors, with the caveat that only a newer macrolide (azithromycin or clarithromycin) be used to ensure adequate coverage of H.
influenzae. Patients with chronic obstructive pulmonary
disorder and a history of use of antibiotics or oral steroids
within the past 3 months may have an increased risk for
infection with H. influenzae and enteric gram-negative
bacilli, in addition to pneumococcus, C. pneumoniae, and
L. pneumophila, and a “respiratory” fluoroquinolone is
recommended. A respiratory fluoroquinolone is one with
predictable activity against pneumococcus, such as levofloxacin or moxifloxacin. Fluoroquinolones also are recommended if first-line therapy fails in the patient, the
patient has confirmed allergy to first-line agents, or when
highly resistant pneumococcus (penicillin minimum inhibitory concentration ⬎ 4 ␮g/mL) is prevalent.
For patients who can be treated in the nursing home
setting and do not require hospitalization, a respiratory
fluoroquinolone or amoxicillin-clavulanate plus a macrolide is recommended as the first choice. A second-generation cephalosporin plus a macrolide is an alternative.
299
Anaerobic coverage should be considered for those patients with a history of loss of consciousness or in persons with gingival or esophageal disease. Antibiotic selection should always consider local epidemiology and
susceptibility patterns.
FOLLOW-UP
Patients treated in the outpatient setting must be monitored
carefully to ensure adherence to the antibiotic regimen and
clinical improvement. Follow-up by telephone or a clinic
visit within 48 to 72 hours is strongly suggested. Patients
who fail to respond despite what seems to be an appropriate
choice of antimicrobial therapy may have complications of
pneumonia, such as empyema, bronchial obstruction, extrapulmonary spread of infection, superinfections, or misdiagnosis of noninfectious causes (eg, congestive heart failure, neoplasm, vasculitis, sarcoidosis, drug reaction,
alveolitis, pulmonary embolism, or hemorrhage).
PREVENTION
All persons aged more than 6 months should receive inactivated influenza vaccine yearly as recommended by the
Advisory Committee on Immunization Practices, Centers
for Disease Control and Prevention.11 Pneumococcal polysaccharide vaccine is recommended for all persons aged
more than 65 years and anyone aged 2 to 64 years with a
chronic health problem, such as heart disease, lung disease,
sickle cell disease, diabetes, alcoholism, and cirrhosis. All
persons aged 2 to 64 years who have an immunosuppressive
condition, such as hematologic malignancy, kidney failure,
nephrotic syndrome, human immunodeficiency virus infection, asplenia, or organ transplant, should receive vaccine.
Anyone aged more than 2 years who lives in an institutional
or group setting is a candidate for pneumococcal vaccine. A
comprehensive discussion of risk factors for invasive pneumococcal infection is published by the Centers for Disease
Control and Prevention.12
References
1. Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases
Society of America/American Thoracic Society consensus guidelines
on the management of community-acquired pneumonia in adults. Clin
Infect Dis. 2007;44(Suppl 2):S27.
2. Almirall J, Bolibar I, Balanzo X, Gonzalez CA. Risk factors for
community-acquired pneumonia in adults: a population-based casecontrol study. Eur Respir J. 1999;13:349.
3. Rubinstein E, Kollef MH, Nathwani D. Pneumonia caused by methicillin-resistant Staphylococcus aureus. Clin Infect Dis. 2008;46(Suppl
5):S378.
4. Marrie TJ. Community-acquired pneumonia in the elderly. Clin Infect
Dis. 2000;31:1066-1078.
5. Craven DE, Palladino R, McQuillen DP. Healthcare-associated pneumonia in adults: management principles to improve outcomes. Infect
Dis Clin North Am. 2004;18:939.
6. Hopstaken RM, Witbraad T, van Engelshoven JM, Dinant GJ. Interobserver variation in the interpretation of chest radiographs for pneumonia in community-acquired lower respiratory tract infections. Clin
Radiol. 2004;59:743.
300
7. Houck PM, Bratzler DW, Nsa W, Ma A, Bartlett JG. Timing of antibiotic
administration and outcomes for Medicare patients hospitalized with community-acquired pneumonia. Arch Intern Med 2004;164:637-644.
8. Fine MJ, Hough LJ, Medsger AR, et al. The hospital admission
decision for patients with community-acquired pneumonia. Arch Intern Med. 1997;157:36.
9. Lim WS, van der Eerden MM, Laing R, et al. Defining community
acquired pneumonia severity on presentation to hospital: an international derivation and validation study. Thorax. 2003;58:377.
The American Journal of Medicine, Vol 124, No 4, April 2011
10. Labarere J, Stone RA, Obrosky DS, et al. Comparison of outcomes for
low-risk outpatients and inpatients with pneumonia. Chest. 2007;131:
480.
11. Centers for Disease Control and Prevention. Preventing seasonal flu
with vaccination. Available at: http://www.cdc.gov/flu/protect/
preventing.htm. Accessed March 1, 2010.
12. Centers for Disease Control and Prevention. Pneumococcal vaccination. Available at: http://www.cdc.gov/vaccines/vpd-vac/pneumo. Accessed March 3, 2010.