++
For further information, see CMDT Part 9-12: Pneumonia
+++
Essentials of Diagnosis
++
Fever or hypothermia, tachypnea, cough with or without sputum, dyspnea, chest discomfort, sweats or rigors (or both)
Bronchial breath sounds, rhonchi, or inspiratory crackles on chest auscultation
Parenchymal opacity on chest radiograph (occasionally not evident at presentation)
Occurs outside of the hospital or within 48 hours of hospital admission
+++
General Considerations
++
The deadliest infectious disease in the United States and routinely among the top 10 causes of death
Risk factors for the development of community-acquired pneumonia (CAP) include
Older age
Excessive alcohol use
Tobacco use
Comorbid medical conditions, especially chronic obstructive pulmonary disease (COPD) or other chronic lung disease
Immunosuppression
Recent viral upper respiratory tract infection (URI)
Prospective studies fail to identify the cause in 30–60% of cases, although bacteria are more commonly identified than viruses
The most common bacterial pathogens
Common viral causes
Assessment of epidemiologic risk factors helps in diagnosing pneumonia due to
Chlamydophila psittaci (psittacosis)
Coxiella burnetii (Q fever)
Francisella tularensis (tularemia)
Endemic fungi (Blastomyces, Coccidioides, Histoplasma)
Sin Nombre virus (hantavirus pulmonary syndrome)
++
Acute or subacute onset of fever, cough with or without sputum, and dyspnea
Rigors, sweats, chills, pleurisy, chest discomfort, and hemoptysis are common
Fatigue, anorexia, headache, myalgias, and abdominal pain can be present
Persons > age 80 may have an atypical presentation, including falls, delirium, lethargy, and anorexia
Physical findings include
Chest examination often reveals inspiratory crackles, rhonchi, and bronchial breath sounds
Dullness to percussion may be found if lobar consolidation or a parapneumonic effusion is present
+++
Differential Diagnosis
++
++