A 32-year-old man comes to the office due to 3 days of fever, malaise, and cough productive of clear sputum. He has had no nasal congestion, rhinorrhea, sore throat, or chest pain. The patient has a history of mild, intermittent asthma and seasonal allergic rhinitis. He does not use tobacco but drinks alcohol occasionally. His 2-year-old son had fever, cough, and rhinorrhea last week. Temperature is 38.3 C (101 F), blood pressure is 120/80 mm Hg, pulse is 92/min, respirations are 20/min, and pulse oximetry is 96% on room air. The oropharynx is normal, and palpation of the neck shows no cervical lymphadenopathy. Lung auscultation reveals crackles at the right lung base and occasional expiratory wheezing. Heart sounds are normal. Which of the following is the best next step in management of this patient?
This patient has fever, malaise, and cough productive of clear sputum. Although these findings are often seen in viral upper respiratory infection, most patients have concurrent upper airway symptoms (eg, rhinorrhea, coryza, sore throat). In addition, the presence of crackles at the right lung base indicate that the alveoli in this area are collapsed by fluid or exudate. This raises concern for pneumonia, a potentially life threatening infection that requires further evaluation with chest x-ray for diagnosis.
CAP is a pulmonary parenchymal infection that may be caused by bacterial (majority), viral (30%), or fungal pathogens. Symptoms often develop acutely and frequently include fever, cough, pleuritic chest pain, and dyspnea. Tachycardia, tachypnea, and pulmonary auscultation abnormalities (eg, focal crackles) may be present. Clinical and physical findings are notoriously poor at predicting the presence of pneumonia (<50% sensitivity). Therefore, even though patients are sometimes diagnosed clinically in practice, guidelines require a lobar, interstitial, or cavitary infiltrate on chest imaging (usually chest x-ray) for confirmation.
Patients with a pulmonary infiltrate are generally treated with empiric antibiotics because rapid differentiation between a viral and bacterial etiology is often difficult; in addition, antibiotics reduce risk of secondary bacterial pneumonia in the setting of primary viral lung infection (Choice G). The presence of a focal infiltrate makes viral bronchitis much less likely than CAP; therefore, symptomatic treatment would not be appropriate.
(Choices A and B) Azithromycin can be used for the outpatient treatment of CAP when local resistance rates in Streptococcus pneumoniae are <25%. Ceftriaxone plus azithromycin is first-line for hospitalized patients (not in intensive care). However, diagnosis with chest x-ray is required prior to treatment.
(Choice D) Mycoplasma pneumoniae is the most common cause of atypical pneumonia (indolent fever, malaise, and cough) and frequently results in the formation of cold agglutinins (not routinely used for diagnosis). However, M pneumoniae is less likely to cause focal findings on lung examination, can be accompanied by extrapulmonary (eg, gastrointestinal) manifestations, and usually causes indolent rather than acute symptoms.
(Choice E) Influenza tends to cause the abrupt onset of systemic (eg, fever, malaise, myalgias) and upper respiratory (eg, rhinorrhea, sore throat) symptoms. This patient has no upper respiratory symptoms.
(Choice F) Sputum and blood cultures are typically not required in the outpatient setting as empiric oral antibiotics (eg, amoxicillin, levofloxacin) are usually curative. An infiltrate on chest x-ray confirms CAP.
Educational objective:
The diagnosis of community-acquired pneumonia requires the presence of a lobar, interstitial, or cavitary infiltrate on chest imaging (eg, chest x-ray). Sputum and blood cultures are typically not required in the outpatient setting as empiric oral antibiotics are almost always curative.