About Pneumonia 2020-03-11

About Pneumonia

1. Basic causes

Pneumonia can be caused by the infection of pathogenic microorganisms, but also by other factors such as radiation damage and allergic reactions. Pneumonia caused by some infections (such as bacteria and viruses) is contagious and can be transmitted through droplets. Pneumonia caused by non-infectious factors is not infectious.

(1) Bacterial infection: such as Streptococcus pneumoniae, Staphylococcus aureus, Klebsiella pneumoniae, Haemophilus influenzae, etc. Among them, Streptococcus pneumoniae is the most common pathogen of bacterial pneumonia.

(2) Viral infection: including respiratory syncytial virus (RSV), parainfluenza virus (types 1, 2, and 3), influenza virus (types A and B), adenovirus, cytomegalovirus, and measles virus. Is the most common cause of pneumonia in children under 5 years of age.

(3) Atypical pathogen infections: including mycoplasma (mycoplasma pneumoniae), chlamydia (chlamydia trachomatis, chlamydia pneumoniae), Legionella infection, and so on.

(4) Parasitic infections: including hydatid, toxoplasma, and schistosomiasis.

(5) Fungal infection: including Candida albicans, Aspergillus, Cryptococcus, Pneumocystis, Mucor and so on.

(6) Non-infection causes: radiation damage, foreign bodies such as food, beverages, saliva or vomitus are inhaled into the lungs, and allergic reactions can cause pneumonia.

2. Pathogenesis

The airways and lungs are continuously exposed to pathogenic microorganisms from the external environment, especially the upper respiratory tract and oropharynx, with normal flora colonization. Under normal circumstances, the defense mechanism of the respiratory system can remove pathogenic microorganisms. The main ways include:

(1) Cough reflex helps to excrete pathogenic microorganisms.

(2) The cell wall of the respiratory tract can prevent pathogenic microorganisms from invading the lungs.

(3) Proteins produced by lung cells can attack pathogenic microorganisms.

(4) Alveolar macrophages can also remove pathogenic microorganisms.

However, if the defense mechanism of the respiratory system is damaged, a large number of pathogenic microorganisms are inhaled and the normal defense ability of the respiratory system is broken, and infectious pathogenic microorganisms are inhaled into the respiratory tract, etc., all can cause pneumonia.

High-risk factors

(1) Crowd: Elderly people over 65 years of age and infants under 2 years of age are at increased risk. Due to the decline in the ability of the elderly to resist the disease, the infant's immune system is underdeveloped and therefore vulnerable to infection.

(2) Suffering from chronic diseases: asthma, chronic obstructive pulmonary disease, bronchiectasis, diabetes, heart failure, chronic liver disease and other diseases, which can weaken the defense mechanism of the lungs and increase the risk of pneumonia.

(3) Bad living habits: long-term smokers and alcoholics have a higher risk of disease.

(4) Medical related factors and trauma: tracheal intubation, tracheotomy, application of ventilator and other medical related factors, as well as open wounds in the chest cavity, can increase the risk of lung infection.

(5) Close contact with patients infected with pneumonia: The pathogenic microorganisms that cause pneumonia are mostly transmitted by respiratory droplets. If healthy people are in close contact with patients infected with pneumonia, patients will cough and sneeze to expel a large number of pathogenic microorganisms, leading to an increased risk of pneumonia in healthy people. .

(6) Impaired immune system: People with AIDS who have received chemotherapy, organ transplants, and long-term use of glucocorticoids or drugs that suppress the immune system have low immunity, are susceptible to infection with pathogenic microorganisms, and have a higher probability of developing pneumonia.

(7) Others: Elderly people with Alzheimer's disease and impaired consciousness have reduced swallowing ability, are prone to aspiration, and have an increased risk of aspiration pneumonia.

Common disease

Lobar (alveolar) pneumonia, lobular (bronchial) pneumonia, interstitial pneumonia, bacterial pneumonia, mycoplasma pneumonia, chlamydia pneumonia, legionella pneumonia, viral pneumonia, fungal pneumonia, parasitic pneumonia (lung Parasitic disease), radiation pneumonitis, chemical pneumonia, lipid pneumonia, community-acquired pneumonia, hospital-acquired pneumonia, etc.


The annual incidences of community-acquired pneumonia (CAP) and hospital-acquired pneumonia (HAP) were (5-11) per 1000 population and (5-10) per 1,000 inpatients. The mortality rate of patients with CAP outpatient treatment is <1% ~ 5%, the average inpatient treatment is 12%, and the number of patients admitted to the intensive care unit is about 40%. The related fatality rate caused by HAP is 15.5% ~ 38.2%.

Seek medical treatment

Emergency (120) indications

1. Persistent high fever and chills;

2. Difficulty breathing, inflammation of the nose, blue lips or nails;

3. Shock signs such as decreased blood pressure, cold limbs, sweating, and fast heartbeat;

4. Restlessness, confusion or altered consciousness, lethargy, and coma;

5. There are other critical situations.

All of these must be promptly dialed an emergency phone or emergency treatment.

Outpatient indications

1. Fever, cough and sputum appear repeatedly or continuously;

2, accompanied by accelerated breathing rate, shortness of breath, chest pain;

3, accompanied by fatigue, headache, sore throat, muscle aches, loss of appetite, etc .;

4. A history of close contact with patients with respiratory infections;

5. Other severe, persistent or progressive symptoms and signs appear.

All of these must be consulted in a timely manner.

Visiting department

If the condition is critical and the symptoms are serious, please go to the emergency department in time; if the condition is stable, you can go to the respiratory department.

Preparation for medical treatment

1. Make an appointment in advance and bring along your ID card, medical insurance card, and medical card.

2. If you have any recent medical experience, please bring relevant medical records, test reports, test sheets, etc.

3. If you take some medicine recently to relieve your symptoms, you can bring a pill box.

4, arrange family members to accompany the doctor.

5. Patients can prepare a list of questions to ask in advance.

What questions may the doctor ask the patient

1. Do you have fever, cough, sputum and other symptoms? When did these symptoms appear?

2. What is your body temperature? How often do you cough?

3. What color is your sputum? Thin or sticky?

4. Do you have any other discomforts, such as headache and sore throat?

5. Have your symptoms worsened recently?

6. Have you had similar symptoms before? What is the original cause?

7. Have you been exposed to patients with respiratory infections?

8. Do you have other underlying diseases?

9. Do you usually smoke? Is it alcohol?

10. Have you been vaccinated against pneumonia or flu?

11. Have you been to other hospitals? What tests and treatments have been done?

What questions can patients ask the doctor

1. What is the most likely cause of my pneumonia? Is there any other possible reason?

2. What checks do I need to do?

3. Is my condition serious? Do I need to be hospitalized?

4. What treatments are available? Are these treatments risky?

5. How long does it take? Can it be cured? Will it recur?

6. Will it be transmitted to others? What should be paid attention to in daily life?

7. I have other diseases that will affect the treatment effect?

8. If medication is needed, what is the dosage and precautions for the medication?

9. Do I need to review? How often?

General prognosis

Generally speaking, patients usually recover quickly after receiving timely treatment and proper care, and the prognosis is good. However, those who are old and infirm, with chronic diseases such as heart, lung, liver, and kidneys, immunodeficiency, extensive lung disease, and severe complications have a poor prognosis.


an examination

1. Physical examination

(1) Check for basic signs such as body temperature, blood pressure, and heart rate.

(2) Auscultation of the lungs to determine whether there are abnormal breathing sounds.

2.Laboratory inspection

(1) Blood routine: Evaluate whether there is an infection, and make a preliminary judgment of bacterial or viral infection based on white blood cell count and classification.

(2) Isolation and cultivation of sputum specimens: sputum collection is convenient, and it is the most commonly used specimen of lower respiratory tract pathogens. If the same bacteria are isolated twice in a row, they can be considered pathogenic.

(3) Blood culture and pleural effusion culture: The same bacteria were isolated from the blood culture and sputum culture of patients with pneumonia, which can be identified as the pathogenic bacteria of pneumonia. If only blood culture is positive, but other reasons such as celiac infection and venous catheter-related infection cannot be used to explain the cause of bacteremia, blood cultured bacteria can also be considered as the pathogen of pneumonia. Bacteria cultured from pleural effusion are basically considered pathogenic bacteria of pneumonia.

(4) Immunological detection: Use known antigens or antibodies to react with the antibodies or antigens of the test specimens, and perform qualitative or quantitative determinations with the help of naked eyes, fluorescence or nuclide labeling techniques. The advantage is fast, simple and unaffected by antibacterial treatment.

(5) Others: Intratracheal suction through artificial airways or fiber bronchoscopy, bronchoalveolar lavage fluid, and anti-contamination sample brushes are traumatic techniques. They are only used in patients with severe problems and low immunity with pulmonary infection Sexual use.

3. Imaging inspection

(1) Chest X-ray examination: It is an important basis for the diagnosis of pneumonia. The range of lesions on the X-ray is an important reference index for evaluating the severity of the disease. Morphological characteristics (solidification of leaf segments, patchy infiltration, nodular shadows, cavity formation, etc.) are not specific for the diagnosis of the etiology, but combined with the history of the disease still have important reference significance for the diagnosis of the speculative pathogen (cause), which can narrow the identification The scope of the diagnosis.

(2) Chest CT examination: It is very helpful to reveal the nature of the lesion, hidden area lesions and other accompanying changes (pleural effusion, mediastinum, and pulmonary lymphadenopathy), and it is suitable for differential diagnosis.

(3) B-ultrasound: It is used to detect pleural effusion and lung parenchymal lesions close to the chest wall, and can guide puncture aspiration and transthoracic biopsy.


A diagnosis can be made based on history, typical symptoms, combined with auscultation of the lungs and changes in pneumonia on chest imaging. After the diagnosis, the doctor may recommend blood tests, sputum culture, blood culture and other tests to further understand the possible pathogenic microorganisms and the severity of the disease that cause pneumonia.

Differential diagnosis

Pneumonia needs to be distinguished from respiratory infections, tuberculosis, lung cancer, and pulmonary thromboembolism.

Respiratory infections

Although respiratory infections have symptoms such as cough, sputum and fever, they have their own characteristics. Upper and lower respiratory infections do not have pulmonary parenchymal infiltration and can be identified by chest X-ray examination.

2. Tuberculosis

There are many symptoms of systemic poisoning, such as low fever in the afternoon, night sweats (sweating during sleep at night, sweating after waking up), fatigue, weight loss, insomnia, and palpitations. Female patients may have menstrual disorders or amenorrhea. X-ray chest radiographs show that the lesions are mostly on the apex of the lungs or above and below the clavicle, with uneven density, dissipating slowly, and can form cavities or spread within the lungs. Mycobacterium tuberculosis can be found in sputum. General antibacterial treatment is not effective.

3. Lung cancer

Most patients have no symptoms of acute infection, sometimes bloodshot sputum, and low white blood cell count on routine blood tests. However, lung cancer can be accompanied by obstructive pneumonia. After the inflammation subsides after antibacterial treatment, the tumor shadow gradually becomes obvious, or hilar lymphadenopathy can be seen, and atelectasis sometimes occurs. If pulmonary inflammation does not dissipate after antibacterial treatment, or pneumonia reappears in the same area after dissipating, follow-up should be closely. For patients with a history of smoking and older patients, CT, MRI, bronchoscopy, and sputum exfoliated cells should be performed if necessary.

4.Pulmonary thromboembolism

There are many risk factors of venous thrombosis, such as history of thrombophlebitis, cardiopulmonary disease, trauma, surgery and tumor, etc. Hemoptysis, syncope, and dyspnea are obvious. X-ray chest radiographs show reduced regional pulmonary vascular texture and sometimes wedge-shaped shadows with tips pointing to the hilum. Hypoxemia and hypocapnia are common in arterial blood gas analysis. Examinations such as D-dimer, CT, pulmonary angiography, radionuclide lung ventilation / perfusion scan, and MRI can help identify.


Non-infectious lung diseases such as interstitial pneumonia, pulmonary edema, atelectasis, and pulmonary vasculitis need to be ruled out.



1. General treatment

(1) Pay attention to rest, add enough protein, calories and vitamins, and drink plenty of water.

(2) Always ventilate and maintain indoor air circulation.

(3) Clear the nasal secretions in time to keep the breathing unobstructed.

2. Drug treatment

(1) Antibacterial drugs: Doctors will select antibacterial drugs that may cover pathogenic microorganisms according to the epidemiological data of pneumonia pathogenic microorganisms in the area. After the initial treatment, specificity will be given based on the patient's response, the results of the etiology culture and the results of drug sensitivity tests Antibacterial drugs. In young adults and patients with community-acquired pneumonia without underlying diseases, penicillins and first-generation cephalosporins are commonly used. Elderly, community-acquired pneumonia with underlying disease or hospitalization, commonly used fluoroquinolones, second- and third-generation cephalosporins, β-lactam / β-lactamase inhibitors or urtapenem, can be combined with large Cyclic lactones. For hospital-acquired pneumonia, second- and third-generation cephalosporins, β-lactam / β-lactamase inhibitors, fluoroquinolones, or carbapenems were selected. For severe pneumonia, a broad-spectrum powerful antibacterial drug is preferred, and the drug is used in a sufficient amount and in combination.

(2) Antiviral drugs: It has been proven that the more effective virus suppressing drugs are beneficial to bavirin, acyclovir, ganciclovir, and oseltamivir.

(3) Antifungal or antiparasitic drugs: Pneumonia caused by fungi or parasites requires antifungal or antiparasitic drugs.

(4) Antipyretic and analgesics: For those with severe fever or pain, ibuprofen or acetaminophen can be used.

(5) Expectorant: When there is too much sputum, you can use expectorant.


(1) Difficulties in breathing may require oxygen through a nasal cannula or an oxygen mask. Respiratory failure may require the use of a ventilator.

(2) Those with septic shock need anti-shock treatment.

Daily care

1. Pay attention to rest to ensure adequate sleep and avoid excessive fatigue.

2. Enhance nutritional intake, ensure sufficient protein and vitamins, and pay attention to drinking more water.

3. Pay attention to indoor air circulation and maintain proper indoor temperature and humidity.

4. Take medicine regularly and regularly according to the doctor's advice, avoid reducing or stopping without authorization, so as not to completely kill the pathogenic bacteria.

5. During the treatment, you should closely observe the changes in your condition. If the symptoms worsen, you should go to the hospital in time.



1. General prevention

(1) Strengthen physical exercise and physical fitness.

(2) Reduce smoking and passive smoking, and do not drink too much alcohol.

(3) Wash your hands frequently, before eating and preparing food, after going to the toilet, and after returning home.

(4) Try to avoid densely populated places and avoid close contact with people with respiratory infections.

2. Vaccination

(1) Common vaccine: Pneumonia vaccine can prevent pneumonia caused by Streptococcus pneumoniae. Influenza vaccine can prevent pneumonia caused by influenza virus and also help prevent bacterial pneumonia. Since the flu virus may be different each year, it needs to be vaccinated every year.

(2) Vaccination population: children and persons over 65 years of age; or persons under 65 years of age with cardiovascular disease, lung disease, diabetes, alcoholism, cirrhosis and immunosuppression.

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