Differentials
Coronavirus disease 2019 (COVID-19)
SIGNS / SYMPTOMS
Residence in/travel to a country/area or territory with local transmission, or close contact with a confirmed or probable case of COVID-19, in the 14 days prior to symptom onset.
Signs and symptoms are similar so it may be difficult to differentiate between the conditions clinically.
The situation is evolving rapidly; see our COVID-19 topic for further information.
INVESTIGATIONS
Real-time reverse transcription polymerase chain reaction (RT-PCR): positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA.
It is not possible to differentiate COVID-19 from other causes of pneumonia on chest imaging.
Acute bronchitis
SIGNS / SYMPTOMS
No dyspnea, no lung crackles, mild presentation. Often related to a viral upper respiratory tract infection.
INVESTIGATIONS
No consolidation on chest x-ray, with frequency related to viral infection.
Congestive heart failure
SIGNS / SYMPTOMS
Peripheral edema, cardiomegaly, hypotension.
INVESTIGATIONS
Bilateral interstitial pattern or pleural effusions seen on chest x-ray.
COPD exacerbation
SIGNS / SYMPTOMS
Increased expectoration and cough, and worsening of dyspnea against a background of COPD. Patient is often a smoker.
INVESTIGATIONS
Chest x-ray shows hyperinflation.
Asthma exacerbation
SIGNS / SYMPTOMS
Symptoms and signs of bronchospasm, with worsening of underlying lung disease.
INVESTIGATIONS
No consolidation on chest x-ray.
Bronchiectasis exacerbation
SIGNS / SYMPTOMS
Increased expectoration and cough, and worsening of dyspnea, with worsening of underlying lung disease. Infections are typically recurrent.
INVESTIGATIONS
No consolidation on chest x-ray.
Tuberculosis
SIGNS / SYMPTOMS
Typically a long history, often with constitutional symptoms. Many patients will have lived in an endemic area.
INVESTIGATIONS
Cavitation on chest x-ray, enlarged lymph nodes, positive purified protein derivative (PPD) skin testing.
Lung cancer or lung metastases
SIGNS / SYMPTOMS
Constitutional symptoms are common.
INVESTIGATIONS
Consolidation on chest x-ray may be multiple, with pleural effusion commonly seen.
Empyema
SIGNS / SYMPTOMS
Constitutional symptoms are common, usually associated with a recent respiratory infection.
INVESTIGATIONS
Pleural effusion seen on chest x-ray. Microbiology of pleural fluid may reveal infecting organism.
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