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.
Real-time reverse transcription polymerase chain reaction (RT-PCR): positive for SARS-CoV-2 RNA.
It is not possible to differentiate COVID-19 from other causes of pneumonia on chest imaging.
Acute onset with a chill followed by a high fever and pleuritic chest pain suggests pneumococcal pneumonia.
Sputum cultures and blood cultures may be positive for Streptococcus pneumoniae or other bacterial pathogens.
Symptoms of dry cough, fever, myalgia, and malaise, which are clinically difficult to differentiate from atypical bacterial pneumonia.
Nasopharyngeal viral cultures may be positive. Relative lymphocytosis on CBC may be detected.
A history of immunosuppression or prolonged course that is not responding to antibacterial therapy suggests tuberculosis.
Sputum cultures and acid fast bacilli stains positive. A cavity on the chest x-ray may be observed.
Travel or exposure in endemic area.
There may be extrapulmonary symptoms (e.g., rheumatologic).
Sputum culture and stain may demonstrate hyphae or yeasts.
Antigen detection assays or polymerase chain reaction may identify specific mycoses (e.g., aspergillosis).
History of HIV or risk factors should raise suspicion.
Special stain of sputum or bronchoalveolar lavage will be positive for Pneumocystis jirovecii.
Absence of fever and/or lack of response to antimicrobial therapy support a diagnosis of pulmonary embolism.
The ventilation-perfusion scan will be positive in pulmonary embolism.
A history of exposure to chemicals or special work conditions should raise suspicion of inhalation/occupational lung injury.
Cultures will be negative. There may be diffuse disease on the chest x-ray.
Course of disease may be rapid with respiratory problems; might present with mediastinal masses. Clusters of cases may occur.
Cultures will be positive for Bacillus anthracis. Mediastinal widening may present in the respiratory forms of the disease.
Course of disease may be rapid with respiratory problems; might present with mediastinal masses. Clusters of cases may occur.
Cultures will be positive for Yersinia pestis. Chest x-ray will show unilateral or bilateral consolidation or alveolar infiltrates.
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