Bacterial pneumonia

Introduction to bacterial pneumonia Bacterial pneumonia (bacterial pneumonia) accounts for 80% of all kinds of pathogen pneumonia in adults. Since the era of antibiotics, the prognosis of bacterial pneumonia has improved significantly, but since the 1960s, the mortality rate has remained high, and some new features of bacterial pneumonia have emerged. Including pathogen spectrum changes, especially in hospitals, the rate of G-bacteria in pneumonia has increased significantly. Although Streptococcus pneumoniae still dominates community-acquired pneumonia pathogens, clinical manifestations tend to be atypical. The rate of bacterial resistance is increasing, so-called refractory pneumonia is common, especially in children, the elderly and immunosuppressed patients, the mortality rate is extremely high, the pathogenic diagnosis level is improved, the antibiotics are rationally applied, the emergence of drug-resistant bacteria is avoided, and support is improved. Treatment is an urgent need to emphasize and solve the clinical treatment of pneumonia. basic knowledge The proportion of the disease: the probability of the population is 0.033% Susceptible people: no specific population Mode of infection: non-infectious Complications: septic shock arrhythmia meningitis

Cause of bacterial pneumonia

According to anatomical classification, pneumonia can be divided into large leaf, lobular and interstitial. For the convenience of treatment, it is classified according to the cause, mainly infectious and physical and chemical properties such as radiation, poison gas, drugs and allergic reactions such as allergies. Pneumonia, etc., the majority of clinical findings are bacterial, viral, chlamydia, mycoplasma, rickettsia, fungi and parasites caused by infectious pneumonia, of which bacteria are most common.

Pathogens of pneumonia (32%):

The pathogens of pneumonia vary greatly depending on the age of the host, the disease and immune function, and the mode of acquisition (community-acquired pneumonia or nosocomial pneumonia). The common pathogens of community-acquired pneumonia are Streptococcus pneumoniae, Haemophilus influenzae, and gold. Staphylococcus aureus, Streptococcus pyogenes, Legionella, anaerobic bacteria and viruses, mycoplasma and chlamydia, while in hospital pneumonia, Pseudomonas aeruginosa and other Pseudomonas, Klebsiella, Escherichia coli, sulcus and gut Bacillus, Proteus, methicillin-resistant Staphylococcus aureus (MRSA) and fungi are common, and most of the aspiration pneumonia is anaerobic infection.

Immunization (17%):

Immune defense mechanisms such as filtration and humidification of inhaled gases, epiglottis and cough reflexes, bronchial cilia mucus excretion systems, body fluids and cellular immune functions, keep the trachea, bronchi and alveolar tissues sterile and impaired immune function (eg Cold, hunger, fatigue, drunkenness, coma, inhalation of poison gas, hypoxemia, pulmonary edema, uremia, malnutrition, viral infections and application of glucocorticoids, artificial airways, nasogastric tubes, etc.) or into the lower respiratory tract When the pathogenic bacteria are more toxic or more abundant, pneumonia is prone to occur. The main way of bacterial invasion is aspiration and inhalation of oropharyngeal colonization. The former is the most important pathogenesis of pneumonia, especially in hospitals. Internal pneumonia and Gram-negative bacilli pneumonia, direct bacterial planting, infection of adjacent sites or other parts of the bloodstream are rare.

Staging of pathological changes (10%):

The typical pathological changes of pneumococcal pneumonia are divided into four stages: early stage is mainly edema fluid and serous precipitation; middle stage is red blood cell exudation; late stage has a large number of white blood cells and phagocytic cells, lung tissue mutation; finally, pneumonia absorption dissipates, antibacterial drugs After application, the development of whole lobaric inflammation is rare. Typical lung consolidation is less, and replaced by pulmonary segmental inflammation. The pathological feature is that there is no destruction of alveolar walls and other lung structures throughout the lesion. Or necrosis, after the pneumonia dissipates, the lung tissue can completely return to normal without leaving fibrosis or emphysema. Although other bacterial pneumonias have similar pathological processes as mentioned above, most of them are accompanied by different degrees of alveolar wall destruction, Staphylococcus aureus pneumonia. The coagulating alcohol produced by the bacteria can form a protective membrane outside the bacteria to kill the phagocytic cells, and the release of various enzymes can lead to the formation of necrosis and abscess in the lung tissue, and the pus can form a pus when the lesion invades or penetrates the pleura. Chest or pus pneumothorax, lung air sac can be formed when the lesion dissipates, and Gram-negative bacilli pneumonia is mostly bilateral lobular pneumonia, often with multiple necrotic cavities or abscesses. Patients can have empyema, dissipation is often incomplete, can cause fibrosis, residual suppuration and bronchiectasis.

Bacterial pneumonia prevention

Old age, with severe underlying diseases, immune function inhibition host pneumonia has a poor prognosis. After the widespread use of antibacterial drugs, the mortality rate of pneumococcal pneumonia has dropped from 30% to 6%, but Gram-negative bacilli, Staphylococcus aureus It is a pneumonia caused by MRSA, the mortality rate is still high, enhance physical fitness, avoid upper respiratory tract infection, and the selective application of vaccine in high-risk patients has certain significance in preventing pneumonia.

Bacterial pneumonia complications Complications , septic shock, arrhythmia, meningitis

Complications have been rare in recent years. Severe infections in toxic patients are prone to septic shock, especially in the elderly, which are characterized by decreased blood pressure, cold limbs, sweating, cyanosis, tachycardia, arrhythmia, and high fever and chest pain. Symptoms such as cough are not prominent. Other complications include pleurisy, empyema, pericarditis, meningitis and arthritis.

Bacterial pneumonia symptoms Common symptoms Lemon color dry cough high heat breathing difficulty rust color shock fatigue face pale hemoptysis convulsion

There are often underlying causes such as cold or fatigue, or chronic obstructive pulmonary disease, heart failure and other basic diseases. One third of patients have a history of upper respiratory tract infection before the disease. Most of the onset is more urgent. Some Gram-negative bacilli pneumonia, pneumonia in the elderly, and pneumonia in hospital are concealed. There are many symptoms such as chills, fever, cough, cough, chest pain. Frequent fever, mostly high fever, after heat treatment can be atypical. There are many coughs and coughs. In the early stage, they have a dry cough. They gradually cough and the amount of sputum varies. The sputum is mostly purulent, the staphylococcus aureus pneumonia is more yellow than the typical sputum; the pneumococcal pneumonia is rust-colored phlegm; the pneumococcal pneumonia is brick red-like jelly; the Pseudomonas aeruginosa pneumonia is pale green; the anaerobic bacteria Infection is often accompanied by odor. The development of the above-mentioned typical sputum after antibacterial treatment is rare. A few have hemoptysis and difficulty breathing. Some have chest pain, and when they involve the pleura, they have acupuncture-like pain. Inferior lobe pneumonia stimulates the pleura, pain can be radiated to the shoulders or abdomen, the latter is easily misdiagnosed as acute abdomen. Systemic symptoms include headache, muscle aches, fatigue, and a few gastrointestinal symptoms such as nausea, vomiting, bloating, and diarrhea. Severe patients may have neurological symptoms such as lethargy, disturbance of consciousness, and convulsions.

Examination of bacterial pneumonia

(1) Chest X-ray examination: The most common manifestation is bronchial pneumonia type change, which usually does not help to determine the pathogen of pneumonia, but some characteristics may be helpful for diagnosis, such as consolidation of the lung, cavity formation or a large amount of pleural effusion More common in bacterial pneumonia, staphylococcal pneumonia can cause obvious lung tissue necrosis, lung balloon, lung abscess and empyema, Gram-negative bacillus pneumonia often shows lower bronchial pneumonia type, easy to form multiple small abscess, diagnosis of pneumonia It has important value, the location of the inflammatory infiltrating shadow, the range, the presence or absence of cavities, and the pleural effusion are related to the pathogen.

X-ray findings of pneumonia from different pathogens:

X-ray manifestations: pathogenic bacteria leaves or segments of low-density flaky infiltration of Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Legionella uniform infiltration (spot or cord-like shadow) Mycoplasma pneumoniae, virus, Mixed infection of anaerobic and non-anaerobic bacteria, diffuse uniform infiltration of the genus Legionella or nodular shadow Legionella, virus, Pneumocystis carinii, Mycobacterium, Aspergillus, Candida, Hematogenous dissemination Sexual infection invasive Staphylococcus aureus, Gram-negative bacteria, anaerobic bacteria, Mycobacterium tuberculosis, Aspergillus.

(B) bacteriological examination: sputum or pleural smear examination, cultivation of pathogenic bacteria and antibiotic sensitivity test. 2 or 3 times in a row for the same bacteria growth, the possibility of pathogenic bacteria is large, only one positive or multiple times for different bacteria growth, the reliability is poor, the bacterial concentration 107cfa/ml is the pathogen, 105107cfa/ml is Suspicious, <105cfa/ml is mostly contaminated bacteria.

(3) Blood examination: white blood cell count and neutrophils generally increase, and there may be a left shift of the nucleus. The white blood cell count may not increase in the frail or severe cases.

(IV) Immunological examination: the use of immunofluorescence, enzyme-linked immunosorbent assay, convective immunoelectrophoresis and other methods to detect antigen or antibody of serum pathogens, to help diagnose. Polymerase chain reaction has a certain significance for the detection of pathogens.

(5) Other examinations: blood gas analysis, liver, kidney function, serum electrolytes, etc., if necessary.

Diagnosis and identification of bacterial pneumonia

Diagnosis can be based on medical history, clinical symptoms, and laboratory tests.

A few non-infectious conditions may have similar manifestations of pneumonia, such as acute respiratory distress syndrome (ARDS), congestive heart failure, pulmonary embolism, chemical gas inhalation, allergic alveolitis, drug pneumonia, radiation pneumonitis, connective tissue disease involving the lungs Department, tuberculosis, leukemia or other malignant tumors in the lung infiltration or metastasis, etc., should be identified, if necessary, diagnostic treatment can be used to confirm the diagnosis.

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