Severe acute respiratory syndrome
Learn about Severe acute respiratory syndrome, its reported features, relevant specialists, and questions to discuss at a medical consultation.
Also known as: SARS; SARS-1
The sources compiled here do not cover: diagnosis, treatment, prevention, prognosis. Ask the treating doctor about these.
What it is
From: Orphanet
A rare pulmonary disease induced by SARS-CoV coronavirus infection, with a reported incubation period varying from 2 to 7 days. Patients present flu-like symptoms, including fever, malaise, myalgia, headache, diarrhoea, and rigors. Dry, nonproductive, cough and dyspnea are frequently reported. Severe cases evolve rapidly, progressing to respiratory distress and failure, requiring intensive care. Mortality rate is 10%. The disease appeared in 2002 in southern China, subsequently spreading in 2003 to 26 countries. Reported human-to-human transmission occurred in Toronto (Canada), Hong Kong Special Administrative Region of China, Chinese Taipei, Singapore, and Hanoi (Viet Nam).
Reported clinical features and what the terms mean
The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.
The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.
- Cough · Very frequent (99-80%)
- A sudden, audible expulsion of air from the lungs through a partially closed glottis, preceded by inhalation.
- Dyspnea · Frequent (79-30%)
- Difficult or labored breathing. Dyspnea is a subjective feeling only the patient can rate, e.g., on a Borg scale.
- Fever · Frequent (79-30%)
- Body temperature elevated above the normal range.
- Headache · Frequent (79-30%)
- Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.
- Immunodeficiency · Frequent (79-30%)
- Failure of the immune system to protect the body adequately from infection, due to the absence or insufficiency of some component process or substance.
- Myalgia · Frequent (79-30%)
- Pain in muscle.
- Respiratory distress · Frequent (79-30%)
- Respiratory distress is objectively observable as the physical or emotional consequences from the experience of dyspnea. The physical presentation of respiratory distress is generally referred to as labored breathing, while the sensation of respiratory distress is called shortness of breath or dyspnea.
- Abnormality of the cardiovascular system · Occasional (29-5%)
- Any abnormality of the cardiovascular system.
- Acute infectious pneumonia · Occasional (29-5%)
- Acute inflammation of the lung due to an infection.
- Chronic lung disease · Occasional (29-5%)
- According to the definitions of the American and British Thoracic Societies, including pulmonary functional tests, X-rays, and CT scans for items such as fibrosis, bronchiectasis, bullae, emphysema, nodular or lymphomatous abnormalities.
- Diabetes mellitus · Occasional (29-5%)
- A group of abnormalities characterized by hyperglycemia and glucose intolerance.
- Hypoxemia · Occasional (29-5%)
- An abnormally low level of blood oxygen.
- Neoplasm · Occasional (29-5%)
- An organ or organ-system abnormality that consists of uncontrolled autonomous cell-proliferation which can occur in any part of the body as a benign or malignant neoplasm (tumor).
- Pharyngitis · Occasional (29-5%)
- Inflammation (due to infection or irritation) of the pharynx.
Other findings in the same source
From: Orphanet
Additional reported features include Respiratory failure requiring assisted ventilation (Occasional (29-5%)); Acute kidney injury (Very rare (<4-1%)). This is a selected summary, not a complete description of the condition.
When it may begin
From: Orphanet
All ages
Inheritance in the source
From: Orphanet
Not applicable
Frequency and the population described
From: Orphanet
Annual incidence: <1 / 1 000 000; Europe; Class only.
Which doctor should you see?
The suggested department for discussing Severe acute respiratory syndrome is Pulmonology, with a pulmonologist / chest physician as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.
This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.
How to prepare for an assessment
Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.
Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.
- What is the likely explanation for the breathing symptoms?
- Would a breathing test or another investigation change management?
- If symptoms worsen, what written action plan should be followed?
Treatment discussions and follow-up
The material gathered for this draft does not provide a complete condition-specific treatment pathway for Severe acute respiratory syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.
Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.
The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.
When to seek emergency help
Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.
This condition is usually assessed by a pulmonologist. Every profile shows the doctor’s registration and what has been checked.
Sources
- Orphanet — Severe acute respiratory syndrome — Orphadata Science, CC BY 4.0
- Human Phenotype Ontology Consortium — terminology definitions — HPO licence; definitions reproduced without alteration
- Government of India — Emergency Response Support System — Official reference for India emergency number
Source: MedlinePlus, National Library of Medicine. Orphadata Science: Free access data from Orphanet. © INSERM 1999; July 2026 data, CC BY 4.0. This product uses the Human Phenotype Ontology (hp/releases/2026-09-01). Only sources listed for this article apply. Source material has been selected and arranged; HPO definitions are reproduced without alteration. No source organisation endorses this compilation. Köhler S et al. The Human Phenotype Ontology project: linking molecular biology and disease through phenotype data. Nucleic Acids Research 2014;42(D1):D966–D974. doi:10.1093/nar/gkt1026.
General information, not advice about your situation. Errors can be reported through the corrections process. Reference TDI-C-2131.