What Is Mycoplasma Pneumonia?

Mycoplasma pneumonia is an acute respiratory infection caused by mycoplasma pneumoniae with pneumonia. Of the pathogens used to be called "primary atypical pneumonia", mycoplasma pneumoniae is the most common. Can cause epidemics, accounting for about 10% of various pneumonia, severe mycoplasma pneumonia can also lead to death.

Basic Information

Causes of Mycoplasma Pneumonia

The main pathogenesis: Mycoplasma pneumoniae can be found in respiratory secretions 2 to 3 days before the onset of disease until a few weeks after the disease is healed. It grows between ciliated epithelium through contact infection, does not invade the lung parenchyma, and has a neuraminic acid receptor on its cell membrane, which can adsorb to the surface of the respiratory epithelial cells of the host, inhibit ciliary activity and destroy epithelial cells, and produce hydrogen peroxide Further cause local tissue damage. Its pathogenicity may be related to patients' allergic reactions to pathogens or their metabolites. After infection, humoral immunity is caused. Most adults already have antibodies in their serum, so they rarely develop disease.

Clinical manifestations of Mycoplasma pneumonia

The incubation period is 2 to 3 weeks, the onset is slow, and about 1/3 of the cases are asymptomatic. It appears in the form of tracheobronchiolitis, pneumonia, tympanitis, etc., and pneumonia is the most severe. At the beginning of the onset, there are weakness, headache, sore throat, chills, fever, muscle aches, loss of appetite, nausea, vomiting, etc., and headache is significant. The fever varies, and can be as high as 39 ° C. Obvious respiratory symptoms appear after 2 to 3 days, such as paroxysmal irritating cough, a small amount of mucus or mucopurulent sputum, and sometimes blood in the sputum. Fever can last 2 to 3 weeks. After the fever returned to normal, there was still a cough, with substernal pain, but no chest pain.

Physical examination revealed mild nasal congestion, runny nose, and moderate congestion of the pharynx. Ear drums often have congestion, and about 15% have tympanitis. The cervical lymph nodes can become swollen. Few cases have maculopapular rash, erythema, or cold sores. There are generally no obvious abnormal signs on the chest, dry or wet rales can be heard in about half, and a small amount of pleural effusion occurs in 10 to 15% of cases.

Mycoplasma pneumonia examination

Blood image

The total number of white blood cells is usually in the normal range, but occasionally it can increase. 25% of patients had leukocytes exceeding 10.0 × 10 ⁹ / L, and a few could reach (25.0 56.0) × 10 ⁹ / L. The classification is slightly increased by neutrophils or eosinophils. Thrombocytopenia. Direct Coombs test can be positive. ESR can be accelerated in the early stages of onset.

2. Culture method

Due to the high nutritional requirements and slow growth of Mycoplasma pneumoniae, it needs to be observed for 10 to 30 days or longer, which is of little help for clinical diagnosis.

3. Serological method

(1) Complement binding test is a widely used serological diagnosis method for the diagnosis of Mycoplasma pneumoniae infection.

(2) Indirect hemagglutination test Mainly detects IgM antibodies.

(3) Enzyme-linked immunosorbent assay For detecting IgM and IgG antibodies. The method is sensitive, specific, fast and economical, and it is a practical and reliable method for the diagnosis of Mycoplasma pneumoniae infection. ELISA kits are now available.

(4) Condensation set test is a non-specific test for the diagnosis of Mycoplasma pneumoniae infection.

4. Nucleic acid hybridization test

Radioisotope (32P, 125I, etc.)-Labeled nucleic acid probe technology was used to detect Mycoplasma pneumoniae. Although this method has high sensitivity and specificity, it also requires high conditions and requires the use of isotopes, so it is difficult to promote this method in clinical practice.

5. Polymerase chain reaction (PCR)

The method has been used to examine clinical specimens of Mycoplasma pneumoniae infection since 1992. From the comprehensive results, the positive rate detected by the PCR method is significantly higher than that of the culture method (the sensitivity is 10 to 100 times higher than that of the ordinary culture method), and it is also significantly higher than that of the serology and probe hybridization methods. Its specificity is also strong, there is no cross-reaction with other mycoplasma, and it is not disturbed by other bacteria contamination in the oral cavity. The time required is short, so the PCR method can be used for early diagnosis to guide the rational use of medicine. When symptoms occur in the central nervous system, a quick and reliable diagnosis is even more necessary. Since this method is quite sensitive, special care should be taken in experimental operations to avoid contamination.

6. X-ray of the lungs

Examination shows a fuzzy cloud-like or uniform shadow, which is denser near the hilum and gradually becomes shallower outward, the edges are unclear and usually do not invade the whole leaf. Most of them are affected by one lobe. The lower lobe is more common, the lower left is the most, and the next is right. There is a small amount of pleural effusion in about 20% of the lateral position, and atelectasis is seen in about 10%. Absorption in 3 weeks, complete absorption takes 4-6 weeks. About 30% of children are accompanied by hilar lymphadenopathy.

Mycoplasma pneumonia diagnosis

Clinical symptoms such as headache, fatigue, myalgia, nasopharyngeal disease, cough, chest pain, purulent sputum and blood sputum, lung X-ray manifestations and laboratory tests such as the condensation test are helpful.

Mycoplasma pneumonia treatment

General treatment

Isolate the respiratory tract, rest, and provide sufficient water and nutrition. Symptomatic treatment: Avoid salicylic acid drugs to prevent hemolysis. Generally, antipyretic and analgesics with slow and long-lasting effects are selected, such as acetylphenol, carbachel calcium, lysamine, and Bupleurum, supplemented with physical cooling during high fever. Resolving Phlegm and Cough. Clear nasal secretions and keep the airway open. Inhale if necessary.

2. Antibacterial treatment