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| What is severe acute respiratory syndrome? |
Cause
On April 16, 2003, the World Health Organization announced the cause of Severe Acute Respiratory Syndrome (SARS) based on the results of a collaborative study conducted by 13 laboratories in 11 countries and regions including the Mainland of China and Hong Kong, Canada and the United States. A new type of coronavirus called SARS coronavirus.
Clinical manifestation
The incubation period is 1 to 16 days, usually 3 to 5 days. Acute onset, highly contagious, with fever as the first symptom, may have chills, body temperature often exceeds 38 ° C, irregular heat or relaxation heat, missed heat, etc., heat stroke is mostly 1 to 2 weeks; accompanied by headache , muscle aches, general malaise and diarrhea. After 3 to 7 days of onset, dry cough, less sputum, occasional bloodshot sputum, lung signs are not obvious. The disease reached a peak in 10 to 14 days. Symptoms of infection, such as fever and fatigue, aggravated, and frequent coughing, shortness of breath and difficulty in breathing. Slightly active, asthma, palpitations, and forced bed rest. This period is prone to secondary infection of the respiratory tract.
After 2 to 3 weeks of progression, the fever subsides and other symptoms and signs are alleviated or even disappeared. The absorption and recovery of lung inflammation changes are slower, and it takes about 2 weeks after normal body temperature to fully absorb and return to normal. Light patients have mild clinical symptoms. Severe patients are seriously ill and prone to respiratory distress syndrome. Children's patients seem to be milder than adults. A small number of patients do not have fever as the first symptom, especially in patients with a recent history of surgery or underlying disease.
An examination
1.Blood routine
At the beginning of the disease, the white blood cell count is usually normal or decreased, lymphocytes are often reduced, and platelets are also reduced in some cases. CD3, CD4 and CD8 T cells were significantly reduced in the T cell subset.
2. Blood biochemical examination
Alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and its isoenzymes can be increased to varying degrees. Blood gas analysis revealed a decrease in blood oxygen saturation.
3. Serological testing
Indirect fluorescent antibody assay (IFA) and enzyme-linked immunosorbent assay (ELISA) have been established in the country to detect SARS virus-specific antibodies in serum. The detection rate of IgG type antibody was low or undetectable in the first week after onset. The detection rate was over 80% at the second weekend, over 95% at the third weekend, and the titer continued to rise, in the third month after the disease. Still maintain a high titer.
4. Molecular biological testing
The RNA of the SARS coronavirus in the blood, respiratory secretions, stools and the like of the patient is examined by reverse transcription polymerase chain reaction (RT-PCR).
5. Cell culture to isolate virus
The patient specimen is inoculated into the cell for culture, and after the virus is isolated, the SARS virus should also be identified by RT-PCR.
6. Imaging examination
Most patients have chest X-ray abnormalities in the early stage of onset, mostly patchy or reticular changes. In the early stage of the onset, there is often a single lesion, and the lesions increase rapidly in the short term, often involving both lungs or single lung and multiple leaves. Some patients progressed rapidly with large patches of shadow. The surrounding areas of the lungs are more common. For patients with chest X-ray without lesions and clinically suspected of the disease, chest X-ray examination should be reviewed within 1 to 2 days. Chest CT examinations are most common with glass-like changes. Lung shadow absorption and dissipation are slower; shadow changes can sometimes be inconsistent with clinical signs and symptoms.
Differential diagnosis
The diagnosis of severe acute respiratory syndrome must exclude other diseases that can explain the epidemiological history and clinical course of the patient. Clinical attention should be paid to the exclusion of upper respiratory tract infection, influenza, bacterial or fungal pneumonia, acquired immunodeficiency syndrome (AIDS) with pulmonary infection, legionellosis, tuberculosis, epidemic hemorrhagic fever, non-infectious interstitial Respiratory diseases such as pulmonary disease, pulmonary eosinophilic infiltration, and pulmonary vasculitis.
1.Treatment
1.General treatment
- Resting in bed.
- To avoid severe cough, severe cough given to the elderly cough; cough to give expectorants.
- If the fever exceeds 38.5 °C, antipyretic analgesics can be used, children should avoid using aspirin, which may cause Reye syndrome; or give physical cooling such as ice application and alcohol rubbing bath.
- Injury, liver, kidney and other organ damage, should be treated accordingly.
2. Oxygen therapy
Shortness of breath should be given to a continuous nasal cannula or mask for oxygen.
- A common and simple method of oxygen supply to the nasal cannula or nasal congestion, suitable for low concentration of oxygen, easy for patients to accept.
- The mask has an adjusting device on the oxygen mask, which can adjust the oxygen concentration in the cover, does not need to be humidified, and consumes less oxygen.
- Tracheal intubation or incision through the cannula or incision jet to give oxygen, and is conducive to the discharge of respiratory secretions and maintain airway patency.
- Ventilator oxygen is the best oxygen therapy route and method, which is often used for the rescue of critically ill patients.
3. Application of glucocorticoids
Treatment with glucocorticoids should have one of the following indications.
- There are symptoms of severe poisoning, and the high fever does not return for 3 days.
- The shadow area of the lungs expanded by more than 50% within 48 hours.
- There is acute lung injury (ALI) or ARDS.
4. Application of antibacterial drugs
In order to prevent bacterial infections, antibiotics should be used to cover common pathogens of community-acquired pneumonia. Clinically, macrolides (such as azithromycin), fluoroquinolones, β-lactams, tetracyclines, etc. can be used, if sputum culture or Clinically, it is suggested to have methicillin-resistant Staphylococcus aureus infection or penicillin-resistant Streptococcus pneumoniae infection, and (nor) vancomycin can be used.
5. Antiviral drugs
So far, there is no sure treatment for effective antiviral drugs, and antiviral drugs can be selected for treatment.
6. Treatment of severe cases
- Strengthen the dynamic monitoring of patients: as much as possible in the intensive care unit.
- Use atraumatic positive pressure mechanical ventilation (NPPV).
- After NPPV treatment, if the oxygen saturation improvement is not satisfactory, invasive positive pressure mechanical ventilation should be performed in time.
- For the occurrence of ARDS cases, it is advisable to directly apply invasive positive pressure mechanical ventilation therapy; if shock or MODS occurs, it should be supported accordingly.
Prevention
1. Control the source of infection
- Epidemic report China has listed Severe Acute Respiratory Syndrome in the First Class of Legal Infectious Diseases implemented by the Law of the People's Republic of China on the Prevention and Control of Infectious Diseases on December 1, 2004, and provides for reporting and isolation according to Class A infectious diseases. Treatment and management. When the disease is discovered or suspected, it should be reported to the health and epidemic prevention agency as soon as possible. Early detection, early isolation, early treatment.
- Isolation and treatment of patients The clinically diagnosed cases and suspected diagnosed cases should be separately observed and treated according to respiratory infectious diseases in designated hospitals.
- Isolation and observation of close contacts For medical observation cases and close contacts, if conditions permit, they should be inspected at the designated place for 14 days. Attention should be paid to ventilation during the isolation observation at home, to avoid close contact with family members, and medical observation by the health and epidemic prevention department to measure body temperature every day.
2. Cut off the route of transmission
- Comprehensive prevention of the community Reduce large-scale mass gatherings or activities, maintain ventilation and air circulation in public places, and eliminate hidden dangers of sewage discharge systems in residential buildings.
- Maintain good personal hygiene habits without spitting, avoid sneezing, coughing, cleaning the nose in front of people, and wash your hands afterwards; ensure ventilation in your home or activity place; wash your hands frequently; avoid places where people are more or relatively closed, Should pay attention to wearing a mask.
- The hospital should set up a fever clinic to establish a special channel for the disease.
3. Protect susceptible populations
Maintain an optimistic and stable attitude, eat a balanced diet, drink more soup, keep warm, avoid fatigue, have enough sleep, and exercise in moderation. These good habits can help improve the body's resistance to severe acute respiratory syndrome. ability.
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