Differentials

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Initial reports suggest that the clinical course of COVID-19 is less severe and the case fatality rate is lower compared with MERS (approximately 2% to 3% for COVID-19 versus 37% for MERS); however, there are no data to confirm this and the situation is rapidly evolving.[149]

Gastrointestinal symptoms and upper respiratory tract symptoms appear to be less common in COVID-19 based on early data.[149][150]

INVESTIGATIONS

Reverse-transcriptase polymerase chain reaction (RT-PCR): positive for MERS-CoV viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

There have been no cases of SARS reported since 2004.

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Initial reports suggest that the clinical course of COVID-19 is less severe and the case fatality rate is lower compared with SARS (approximately 2% to 3% for COVID-19 versus 10% for SARS); however, there are no data to confirm this and the situation is rapidly evolving.[149]

Gastrointestinal symptoms and upper respiratory tract symptoms appear to be less common in COVID-19 based on early data.[149][150]

INVESTIGATIONS

RT-PCR: positive for SARS-CoV viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Differentiating COVID-19 from community-acquired respiratory tract infections is not possible from signs and symptoms.

INVESTIGATIONS

Blood or sputum culture or molecular testing: positive for causative organism.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Differentiating COVID-19 from community-acquired respiratory tract infections is not possible from signs and symptoms. However, early reports suggest that sore throat is less common in COVID-19.[150]

INVESTIGATIONS

RT-PCR: positive for influenza A or B viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Differentiating COVID-19 from community-acquired respiratory tract infections is not possible from signs and symptoms. However, early reports suggest that coryza and sore throat are less common in COVID-19.[150]

INVESTIGATIONS

RT-PCR: positive for causative organism, or negative for SARS-CoV-2 viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

May be difficult to differentiate based on epidemiological history as avian influenza H7N9 is endemic in China.

Close contact with infected birds (e.g., farmer or visitor to a live market in endemic areas), or living in an area when avian influenza is endemic.

Early reports suggest that sore throat is less common in COVID-19.[150]

INVESTIGATIONS

RT-PCR: positive for H7-specific viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Close contact with infected birds (e.g., farmer or visitor to a live market in endemic areas), or living in an area when avian influenza is endemic.

Early reports suggest that sore throat is less common in COVID-19.[150]

INVESTIGATIONS

RT-PCR: positive for H5N1 viral RNA.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Lack of travel history to mainland China or other affected areas, or of close contact with an infected person in the 14 days prior to symptom onset.

Differentiating COVID-19 from community-acquired respiratory tract infections is not possible from signs and symptoms.

Adenovirus and Mycoplasma should be considered in clusters of pneumonia patients, especially in closed settings such as military camps and schools.

INVESTIGATIONS

Blood or sputum culture of molecular testing: positive for causative organism.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Consider diagnosis in endemic areas, especially in patients who are immunocompromised.

History of symptoms is usually longer.

Presence of night sweats and weight loss may help to differentiate.

INVESTIGATIONS

Chest x-ray: fibronodular opacities in upper lobes with or without cavitation; atypical pattern includes opacities in middle or lower lobes, or hilar or paratracheal lymphadenopathy, and/or pleural effusion.

Sputum acid-fast bacilli smear and sputum culture: positive.

Molecular testing: positive for Mycoplasma tuberculosis.

SIGNS / SYMPTOMS
INVESTIGATIONS
SIGNS / SYMPTOMS

Suspect neutropenic sepsis in patients with a history of recent systemic anticancer treatment who present with fever (with or without respiratory symptoms) as this can be rapid and life-threatening.[151]

Symptoms of COVID-19 and neutropenic sepsis may be difficult to differentiate at initial presentation.

INVESTIGATIONS

CBC: neutropenia.

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