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Community Acquired Pneumonia
Ambulatory Medicine
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Diagnosis
• Symptoms: cough, fevers/chills, malaise,
pleuritic chest pain, shortness of breath
• Radiological findings: new infiltrate (s) on CXR
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Triaging : IP vs. OP Treatment
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Triaging Con’t
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Outpatient Antibiotics
Course: 5-7 days
A
ntibiotic Therapy for Community-Acquired Pneumonia in Outpatients
Risk Factors
Treatment
Previously healthy and no risk factor(s) for Macrolide (azithromycin, clarithromycin,
drug-resistant Streptococcus pneumoniae or erythromycin) or doxycycline
Respiratory fluoroquinolone
(moxifloxacin, gemifloxacin, or
levofloxacin) or β-lactama plus a
macrolide or doxycycline
Risk factor(s) for drug-resistant S.
pneumoniae or underlying comorbidities
aAmoxicillin,
1 g every 8 hours, or amoxicillin-clavulanate, 2 g every 12 hours
(preferred), or cefpodoxime or cefuroxime, 500 mg twice daily (alternative).
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Additional Inpatient Labs
• Blood cultures
• Sputum cultures (for pathogen directed
therapy if in ICU)
• Leigonella urine antigen
• S. pneumo antigen
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Inpatient Antibiotics
Empiric Antibiotic Therapy for Community-Acquired Pneumonia in Inpatients
Inpatient Setting
Treatment
Medical ward
β-lactama plus a macrolide or doxycycline; or
respiratory fluoroquinolone (moxifloxacin,
gemifloxacin or levofloxacin)
Intensive care unit
β-lactamb plus either azithromycin or a
fluoroquinolonec; if penicillinallergic, a respiratory
fluoroquinoloned plus aztreonam
Antipseudomonal β-lactam with pneumococcal
coverage (cefepime, imipenem, meropenem, or
piperacillin-tazobactam) plus ciprofloxacin or
If risk factor(s) for Pseudomonas aeruginosa or gram- levofloxacin (750 mg); or antipseudomonal β-lactam
negative rods on sputum Gram stain
with pneumococcal coverage plus an aminoglycoside
plus azithromycin; or antipseudomonale β-lactam
with pneumococcal coverage plus an aminoglycoside
plus a respiratory fluoroquinolone
If risk factor(s) for CA-MRSA or compatible sputum
Gram stain
Add vancomycin or linezolid to β-lactamb plus either
azithromycin or a fluoroquinolonec
Cefotaxime, ceftriaxone, or ampicillin; ertapenem is an alternative in patients with an increased risk of
enteric gram-negative pathogens (not P. aeruginosa).
bCefotaxime, ceftriaxone, or ampicillin-sulbactam.
eAztreonam can be used in a patient with a severe β-lactam allergy.
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Follow-up/Prognosis
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Consider follow-up CXR to document clearance of pulmonary infiltrates and
determine the presence of a possible pulmonary malignancy 6 to 8 weeks after
completing treatment for patients who are older than 40 years of age and for
smokers.
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Outpatients and hospitalized patients who were treated for CAP should generally
have a follow-up office visit 10 to 14 days after completing therapy.
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Counsel on smoking cessation if smokers.
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Studies have shown that the median time for resolution of respiratory symptoms
in patients with CAP is 14 days, one third of patients continue to have at least one
pneumonia-related symptom at 28 days.
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Patients who recover from an episode of CAP are at significantly increased risk of
dying, but usually due to their comorbidities such as COPD and cardiovascular
disease.
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MKSAP Q’s
Q34. A 26-year-old man is evaluated for a 3-day history of fever, myalgia, dry
cough, and malaise. He has no known drug allergies, and the remainder of
the medical history is noncontributory.
On physical examination, temperature is 38.3 °C (100.9 °F), blood pressure is
125/75 mm Hg, pulse rate is 95/min, and respiration rate is 16/min. Oxygen
saturation is 100% with the patient breathing ambient air. Crackles are heard
in the left lung base.
Chest radiograph shows left lower lobe airspace disease.
Which of the following oral agents is the most appropriate treatment?
A
B
C
D
Amoxicillin
Azithromycin
Cefuroxime
Ciprofloxacin
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Answer to Q34
This patient should be treated with azithromycin. His clinical presentation and
radiographic findings are consistent with community-acquired pneumonia (CAP) with
no risk factors for resistant S. pneumo. In outpatients, risk factors for drug-resistant
Streptococcus pneumoniae infection influence the selection of empiric therapy. These
risk factors include:
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age > 65 years,
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recent (within the past 3 months) β-lactam therapy,
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medical comorbidities,
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immunocompromising conditions and immunosuppressive therapy,
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alcoholism,
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and exposure to a child in day care.
Amoxicillin would not provide coverage for the atypical pathogens or all H. influenzae
strains because an increasing number of strains are β-lactamase producing.
Cefuroxime will provide coverage for drug-sensitive S. pneumoniae and H. influenzae
but not for atypical pathogens. Ciprofloxacin has very poor activity against S.
pneumoniae and should never be used as empiric therapy for CAP.
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MKSAP Q’s
Question 46 of 108
A 47-year-old man is admitted to the hospital with community-acquired pneumonia. He has hypertension and a 25pack-year smoking history. His only current medication is chlorthalidone.
On physical examination, the patient is in mild respiratory distress. Temperature is 40.1 °C (104.2 °F), blood pressure is
145/85 mm Hg, pulse rate is 130/min, and respiration rate is 16/min. Oxygen saturation is 89% with the patient
breathing ambient air. Pulmonary examination demonstrates dullness to percussion with bronchial breath sounds
localized to the right lung base.
A chest radiograph shows right lower lobe consolidation without significant pleural effusion. Intravenous ceftriaxone
and azithromycin are initiated. On the second hospital day, blood cultures obtained on admission are positive for grampositive cocci in pairs and chains. The ceftriaxone is continued and the azithromycin is stopped.
On the morning of hospital day 3, the patient is feeling better, has been afebrile for the past 12 hours, and is eating and
drinking well. The blood culture isolate is identified as Streptococcus pneumoniae susceptible to penicillin. Temperature
is 37.0 °C (98.6 °F), blood pressure is 140/80 mm Hg, pulse rate is 88/min, and respiration rate is 16/min. Oxygen
saturation is 97% with the patient breathing ambient air.
Which of the following is the most appropriate management?
A
B
C
D
Discharge on oral levofloxacin to complete 7 days of therapy
Discharge on oral amoxicillin to complete 14 days of therapy
Discharge on oral amoxicillin to complete 7 days of therapy
Switch to oral amoxicillin and discharge tomorrow, if stable
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Answer to Q46
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Key Point
Hospitalized patients with bacteremic community-acquired pneumonia who respond promptly to
therapy do not require a more prolonged course of intravenous therapy and can be discharged
home on oral medication when they are clinically stable.
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This patient with bacteremic pneumococcal pneumonia should be discharged on oral amoxicillin to
complete 7 days of therapy. His physical examination findings on hospital day 3 (afebrile, pulse rate
≤100/min, respiration rate ≤24/min, and systolic blood pressure ≥90 mm Hg) plus normal oxygen
saturation while breathing ambient air indicate that he is clinically stable and should be considered
for discharge. In addition, patients considered stable for discharge should have a normal (or
baseline) mental status and be able to tolerate oral therapy. The presence of pneumococcal
bacteremia does not warrant a more prolonged course of intravenous therapy. Once patients are
clinically stable, they are at very low risk for subsequent clinical deterioration and can be safely
discharged from the hospital.
Levofloxacin would provide unnecessarily broad-spectrum coverage for this patient's penicillinsusceptible pneumonia, and levofloxacin would be a more expensive treatment option.
Seven days of therapy is sufficient for treatment of community-acquired pneumonia in most
patients, especially those who have a prompt clinical response to treatment, even in the setting of
bacteremic infection. A 14-day treatment regimen would be unnecessarily long for this patient.
Studies have shown that continued observation after switching from intravenous to oral therapy is
not necessary.
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MKSAP Q’s
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Return to the Answer Sheet 2.7777777777777777% correct
97.22222222222221% unanswered
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Question 50of 108
A 48-year-old woman is admitted to the hospital with a 1-week history of nasal congestion, rhinorrhea, dry cough,
fever, chills, and myalgia. She was beginning to feel better until 48 hours ago when she developed a recurrence of
fever and chills, a cough productive of blood-streaked yellow sputum, and right-sided pleuritic chest pain. She has
had no recent hospitalizations. Medical history is significant for type 2 diabetes mellitus. She has no history of
tobacco, alcohol, or recreational drug use. Current medications are metformin and glipizide.
On physical examination, temperature is 39.0 °C (102.2 °F), blood pressure is 100/50 mm Hg, pulse rate is
110/min, and respiration rate is 24/min. Crackles are heard over the right lateral chest with egophony and
increased fremitus.
Laboratory studies indicate a leukocyte count of 20,000/µL (20 × 109/L), a blood urea nitrogen level of 28 mg/dL
(10.0 mmol/L), and a serum creatinine level of 1.3 mg/dL (114.9 µmol/L). Chest radiograph shows right middle
lobe airspace disease with a small area of cavitation and blunting of the right costophrenic angle.
Which of the following is the most appropriate empiric treatment of this patient?
AAztreonam
BCeftriaxone and azithromycin
CCeftriaxone, azithromycin, and vancomycin
DMoxifloxacin
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Answer to Q50
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Key Point
Community-associated methicillin-resistant Staphylococcus aureus pneumonia can occur following an influenzalike illness and requires initial empiric antibiotics with ceftriaxone or cefotaxime and azithromycin or doxycycline
plus vancomycin.
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Educational Objective
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The most appropriate empiric treatment is ceftriaxone, azithromycin, and vancomycin. The patient has no risk
factors for health care–associated pneumonia; therefore, initial empiric antibiotic therapy would include
ceftriaxone (or cefotaxime) and azithromycin (or doxycycline) to provide coverage for the most common
community-acquired pneumonia (CAP) pathogens
However, the presence of a cavitary infiltrate warrants consideration of additional pathogens.
In this patient with no risk factors for aspiration pneumonia, involvement of Staphylococcus aureus,
including possible community-associated methicillin-resistant S. aureus (CA-MRSA) infection, is a consideration.
CA-MRSA pneumonia can occur following an influenza-like illness; the classic history is a viral syndrome that seems
to be improving and then suddenly worsens. Because this patient with a cavitary infiltrate and influenza-like
prodrome may have S. aureus infection, initial empiric antibiotics should include coverage for CA-MRSA.
Consequently, vancomycin should be added to ceftriaxone and azithromycin.
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Aztreonam provides coverage only for aerobic gram-negative rods. Although gram-negative pathogens can cause
necrotizing pneumonia, initial empiric coverage should not be limited to only gram-negative organisms.
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Moxifloxacin does not provide adequate coverage for CA-MRSA.
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References
1. E. Halm, et al. “Management of Community
Acquired Pneumonia.” NJEM, Vol. 347, No
25. December 19, 2002. www.nejm.org
2. “Community Acquired Pneumonia.” MKSAP
16 Online, Infectious Disease.
https://mksap16.acponline.org/groups/id/topics
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