History and exam

Key diagnostic factors

Recent travel (within 10 days of the onset of symptoms) to a foreign or domestic location with documented or suspected recent transmission of SARS,[21] close and prolonged contact with an infected individual,[22] or working in research laboratories on SARS coronavirus (CoV).[24]

Rapid onset of a persistent temperature 38°C (100.4°F) or more is an early symptom and sign. Afebrile cases of SARS can occur in older adults.[4][36]

Common in the early respiratory phase (2-7 days from the onset of symptoms) of the disease. Usually non-productive.

Prominent in the prodromal phase of the disease. The patient complains of muscle aches.

Prominent later in the course of the disease (8-12 days from the onset of symptoms). Ranges from mild to severe.

Other diagnostic factors

Usually associated with fever.

Present in the prodromal phase of the disease.

Usually present in the prodromal phase of the disease.

Occurs in 20% to 25% of the patients, usually late in the course of the disease (second week) and together with recurrence of fever. Usually watery without blood or mucus.[11]

A respiratory rate of >20 breaths per minute is present in patients with respiratory distress.

Usually present in patients with fever and/or respiratory distress.

A low oxygen saturation is present in patients with respiratory failure progressing to ARDS.

Non-specific symptom, present in many viral infections. Reported frequency up to 19.5%[1]

May be present early in the course of disease.

May be present, but cough is usually non-productive.

If present, appears late in the course of the disease.

If present, appears late in the course of the disease.

Appears mainly in children and infants, who present with a milder course of the disease with associated rhinorrhoea in 50% of cases.[37]

Non-specific symptom, present in many viral infections. Reported frequency varies from 4.2% to 43%.[1]

Common symptom of many viral infections. Reported frequency up to 10.4%.[1]

Reported frequency 3.5%.[1]

A severe acute neurological syndrome has been reported in patients who developed status epilepticus. SARS coronavirus (CoV) RNA has been detected in cerebrospinal fluid.[38]

May be present in older adult patients, who often have an atypical presentation of symptoms.[39]

Present in less than one third of cases. Clinically less severe than would be expected from the radiological findings.[3]

Auscultation of the chest may reveal inspiratory crackles.

Auscultation of the chest may reveal bronchial breathing.

Risk factors

History of recent travel, within 10 days of the onset of symptoms, to a foreign or domestic location with documented or suspected recent transmission of SARS raises suspicion of the infection.[21]

Risk of transmission is enhanced by close, prolonged contact with an infected individual.[22] Transmission in hospitals was a major factor in the amplification of outbreaks, and a significant proportion of those affected were healthcare workers. Healthcare workers, especially those who are exposed to respiratory secretions of a SARS patient (for example, when intubating, suctioning, manipulating oxygen masks, or applying non-invasive ventilation), are at increased risk of infection. In addition, household members in close proximity to a SARS patient, such as those involved in direct patient care, have a higher risk of acquiring SARS.[23]

Cases of SARS infection have been reported in research laboratories working on SARS-CoV.[24] Providing guidelines for biosafety standards and maintaining continuous vigilance can minimise the risk of such transmission.

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