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 of viral pneumonia caused by COVID-19 and pneumonia caused by bacteria (either primary or secondary to COVID-19) are similar so it may be difficult to differentiate between the conditions clinically.
COVID-19 viral pneumonia may be more likely if the patient presents with a history of typical COVID-19 symptoms for about a week, severe myalgia, anosmia, breathlessness, and absence of pleuritic pain.
A bacterial cause of pneumonia may be more likely if the patient becomes rapidly unwell after only a few days of symptoms and presents with pleuritic pain, purulent sputum, and no history of typical COVID‑19 symptoms.
This topic covers pneumonia caused by COVID-19 as a differential diagnosis only. For more detail on the diagnosis and management of community-acquired pneumonia caused by COVID-19, see our topic Coronavirus disease 2019 (COVID-19).
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.
No dyspnoea, no lung crackles, mild presentation. Often related to a viral upper respiratory tract infection.
No consolidation on CXR, with frequency related to viral infection.
Peripheral oedema, cardiomegaly, hypotension.
Bilateral interstitial pattern or pleural effusions seen on CXR.
Increased expectoration and cough, and worsening of dyspnoea against a background of COPD. Patient is often a smoker.
CXR shows hyperinflation.
Symptoms and signs of bronchospasm, with worsening of underlying lung disease.
No consolidation on CXR.
Increased expectoration and cough, and worsening of dyspnoea, with worsening of underlying lung disease. Infections are typically recurrent.
No consolidation on CXR.
Typically a long history, often with constitutional symptoms. Many patients will have lived in an endemic area.
Cavitation on CXR, enlarged lymph nodes, positive purified protein derivative (PPD) skin testing.
Constitutional symptoms are common.
Consolidation on CXR may be multiple, with pleural effusion commonly seen.
Constitutional symptoms are common, usually associated with a recent respiratory infection.
Pleural effusion seen on CXR. Microbiology of pleural fluid may reveal infecting organism.
Suspect pulmonary embolism in a patient with acute onset of dyspnoea, pleuritic chest pain, or features of deep vein thrombosis. In general, symptoms developing within minutes are more suggestive of pulmonary embolism than of community-acquired pneumonia.
Cough is usually non-productive.
Fever is generally lower in pulmonary embolism (i.e., below 39°C [102.2°F]).
Multiple-detector computed tomographic pulmonary angiography (CTPA): direct visualisation of thrombus in a pulmonary artery; appears as a partial or complete intraluminal filling defect.
May be difficult to differentiate on the basis of signs and symptoms. In general, symptoms developing within minutes are more suggestive of pneumothorax than of community-acquired pneumonia.
Spontaneous pneumothorax may occur as a complication of pneumonia.
CXR: presence of a visceral pleural line.
May be difficult to differentiate on the basis of signs and symptoms.
Acute hypersensitivity pneumonitis lasts only a few days and recurs with each additional exposure.
Immunological response to causative antigen: positive.
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