Hospital-acquired pneumonia in the elderly

Introduction to acquired pneumonia in the elderly In-hospital acquired pneumonia (nosocomialpneumonia) refers to pneumonia caused by pathogens in the lower respiratory tract of the elderly under special circumstances. This infection does not exist when the patient is admitted to the hospital, nor is it in the incubation period of infection, but is hospitalized 48 hours after hospitalization (including old age). What happens in nursing homes, rehabilitation homes, but also those who are infected after hospitalization and are discharged from hospital, so it is necessary to exclude other pulmonary infectious diseases that are latent during this period. Hospital-acquired pulmonary infection is an important area of clinical medicine, preventive medicine, hygiene and hospital management in recent years. Countries have invested a lot of manpower, material resources and financial resources to conduct in-depth and meticulous research. The disease not only poses a huge threat to the safety of human life, but also causes huge losses to the social wealth. basic knowledge Sickness ratio: 0.05%-0.08% Susceptible people: the elderly Mode of infection: respiratory transmission Complications: respiratory failure, heart failure, pulmonary edema, arrhythmia, pulmonary encephalopathy, shock, acute myocardial infarction, pleurisy, empyema

The cause of acquired pneumonia in the elderly

Causes:

Monitoring studies at home and abroad have found that the predisposing factors for acquired pulmonary infection in elderly hospitals are: tracheal intubation and/or mechanical assisted ventilation, thoracic and abdominal surgery, unconsciousness, coma (especially those with closed head injury), and a large number of Aspiration, chronic lung disease and elderly (age older than 50 years old), other risk factors are: ventilator pipe replacement is not timely, autumn and winter, stress ulcer bleeding prevention medication (ranitidine, acid-resistant Agents, antibiotics, severe trauma and recent intramyocardial bronchoscopy are used when indwelling nasogastric tubes. Foreign studies have found that the incidence of nosocomial pneumonia after thoracic and abdominal surgery is 38 times higher than that of other sites. Foreign studies report that using machinery Ventilation therapy is one of the important causes of hospital-acquired pulmonary infection.

Pathogenesis:

1. Morphological changes of the respiratory system in the elderly: with the increase of age, the thoracic anterior tilt, the posterior curvature of the spine, the ribs disappear from the posterior and anteroposterior physiology, and become horizontal, resulting in the expansion of the anteroposterior diameter of the thorax to the barrel, plus Degenerative calcification of costal cartilage, decreased contractility of the chest muscles, and decreased constriction of the thoracic activity.

The nasal mucosa and bronchial mucosa of the elderly are atrophied, and the bronchial cartilage also exhibits elastic fibers with age. The proportion of collagen fibers increases, and calcification or ossification occurs. The ciliary movement is weakened, and the terminal bronchiole epithelial cells may be degenerative changes, bronchial glands. Hyperplasia, changes in eosinophils in epithelial cells with abnormal increase in mitochondria can be observed by electron microscopy. These may be the result of degenerative changes. Alveolar wall and alveolar duct elasticity decrease, alveolar duct dilatation, alveolar enlargement, rupture The pulmonary capillaries are narrowed or broken, the pulmonary capillary bed is reduced, and the elastic retraction force of the lung is decreased. In addition, the elastic blood vessels and muscular blood vessels of the pulmonary artery system cause endometrial fibrosis, and the pulmonary circulation is a low-pressure system, and the system of the system of the systemic circulation. Different sexual load, the general elastic artery of the lung also grows with age, and the intimal hypertrophy caused by the proliferation of muscle fiber buds is also likely to cause atherosclerotic changes after middle age.

These physiological changes cause the protective reflex of the upper respiratory tract to weaken, the responsiveness of the larynx decreases, the pathogen easily enters the lower respiratory tract, and the cilia mucociliary function decreases, which does not well enter the lower respiratory tract and alveoli from the outside, the oral cavity and the upper respiratory tract. Dust, physical debris and secretions are quickly eliminated, so that pathogens can grow in the trachea and in the lungs.

2. Changes in lung function in the elderly: The changes in lung function in the elderly are mainly manifested in decreased lung capacity, decreased diffuse function, decreased oxygen saturation and decreased ventilatory response. After middle age, especially after 40 years of age, lung capacity with age The increase and decrease year by year, the alveolar area and volume of the elderly are reduced, the alveolar area in the 30s is about 75m2, and the reduction is about 2% every 10 years, the lung tissue in the 20th is 11%, and the 80% is reduced. At 7%, in addition, the arterial oxygen partial pressure PaO2 also decreases with age, generally PaO2 (mmHg) = 103.5-0.42 × age, the above physiological changes, resulting in more common hypoxemia after pulmonary infection in the elderly Symptoms, such as the original chronic obstructive pulmonary disease, are prone to respiratory failure, recurrent hypoxemia and respiratory failure further impair lung function.

3. The immune function of the elderly declines: The immune function is the defensive reaction of the body, and is an important function for the body to recognize and eliminate external damage to maintain the balance and stability of the internal environment.

(1) Cellular immunization: It is considered that not only peripheral T lymphocytes are 70% to 75% of young people over 60 years old, but their functions are also abnormal, and T lymphocyte reactivity which produces effects after antigen sensitization increases with age. However, the lymphocyte conversion rate of peripheral blood is significantly lower than that of young people. It is reported that the decrease of interleukin-2 (IL-2) in the elderly may be related to the decline of cellular immune function, and the cellular immune function of healthy elderly is significantly reduced. The cellular immune function of human lung infection is more significantly reduced, which is also an important reason for the elderly to be susceptible to lung infection, but not easy to cure.

Lysozyme is an important lysozyme synthesized by macrophages. It can better reflect the functional status of macrophages. There are a certain number of macrophages in the normal respiratory tract. The lysozyme secreted by it is present in its airway. Mucosal surface secretions, in the synergistic action of complement and secretory IgA can cause cell lysis, have a strong bactericidal effect, the cellular immune function of the lung infection in the elderly, especially the reduction of macrophage function, the defense ability against infection Lowering, this may also be another reason for the slow absorption and poor efficacy of lung infection in the elderly.

(2) Humoral immunity: It has been reported that the respiratory secretion of the elderly is decreased, so that the ability of the respiratory tract defense microorganisms, endotoxin and other antigenic substances to invade the mucosa is weakened, so it is easy to cause respiratory infection and injury. The ability of cells to convert antigen-stimulated cells to secrete specific antibodies also decreases with age, which is one of the reasons for the increased incidence of lung infection in the elderly.

(3) Non-specific immune function: the neutrophil phagocytosis ability of the elderly is not reduced, but its chemotactic ability is significantly decreased, adhesion is increased, total complement activity, plasma fibronectin content is decreased, the above changes It is also a factor that constitutes a decline in immune function in the elderly and a decline in the body's defense ability.

4. Increased bacterial colonization in oropharynx: The healthy young population may contain a variety of bacteria in the pharynx. Under normal circumstances, the enzyme protein in the saliva and the secretory properties prevent the bacteria from adhering to the mucosal surface, so the bacteria cannot adhere to the surface of the mucosa. It is adhered to the secretions on the mucosa and cleared with secretions. Studies have shown that the normal population of the genus Streptococcus mutans can inhibit the growth of Streptococcus aureus and aerobic Gram-negative bacilli, and the common Bacteroides melanosus It can inhibit the growth of Klebsiella, Escherichia coli, Mycoplasma and Serratia, and the flora is in a relatively balanced state. Generally, human Gram-negative bacilli are rarely cultured in throat swabs, and the Gram-negative bacilli rate is less than 18%. Staphylococcus aureus, yeast is rarely detected, but the antibacterial mechanism of the pharynx in elderly patients is often destroyed. The detection of Gram-negative bacilli is higher than that of young people. The dysbacteriosis is more serious during hospitalization. The normal flora of oropharynx is as follows. Streptococcus mutans, Neisseria, pneumococcus and Haemophilus influenzae decreased, while Pseudomonas aeruginosa, Acinetobacter increased significantly, Staphylococcus aureus, yeast also increased significantly .

Large doses during hospitalization, long-term use of antibiotics, chest and abdomen surgery - such as affecting cough reflex, mucus-cilia system dysfunction, gastrointestinal dysfunction, decreased gastric juice secretion, decreased gastric acid, etc. are important for the growth of oropharyngeal colonization Factors, the elderly lung infection is mainly caused by inhalation of oropharyngeal pathogens, the proportion of lung infection caused by blood is very small, 50% of normal people and 70% of even those with damage can inhale during sleep, the elderly laryngeal mucosa atrophy The feeling of the throat is reduced, often causing dysphagia, making food easy to break into the lower respiratory tract, and the colony of the oropharynx is also prone to pneumonia in the lower respiratory tract.

Correlation between risk factors and pathogenic distribution: Staphylococcus aureus: coma, head trauma, recent influenza virus infection, diabetes, renal failure, Pseudomonas aeruginosa: long-term residence in ICU, long-term application of glucocorticoids, prior antibiotics, Bronchiectasis, neutropenia, advanced AIDS, Legionella: application of glucocorticoids, endemic or epidemic factors, anaerobic bacteria: abdominal surgery, visible inhalation.

5. Other:

(1) High and low body: The function of various systems and organs is reduced, the ability to keep out cold is reduced, and it is susceptible to cold infection, followed by pulmonary infection.

(2) comorbidities: closely related to pulmonary infection in the elderly, due to mobility disorders or long-term bed rest and inconspicuous swallowing movements, elderly patients with pulmonary infection, myocardial infarction or heart failure due to inconvenient bed rest, Pulmonary congestion, airway secretions are difficult to discharge, resulting in lung infection is not easy to heal, resulting in slow absorption of pneumonia, and easy to occur repeatedly.

(3) Long-term sleep disorder: conventional sleeping pills, sedative hypnotics are unfavorable to the respiratory function of the elderly, inhibiting respiratory and respiratory protective reflexes, thereby lowering the blood oxygen level and carbon dioxide retention in the elderly, after sleeping The cough reflex is weakened, the sputum is not easy to discharge, or the oropharynx is secreted into the lower respiratory tract without a reflective cough.

(4) Low level of superoxide dismutase (SOD): the acute pneumonia period will decrease further. After the same time, it can not return to normal level like young pneumonia. This indicates that the basic level of free radicals in the elderly is high. Further increase, but not reach the so-called "peak concentration" for rapid sterilization, which may be another reason why the elderly are prone to pneumonia, the disease is heavier, and prolonged unhealed.

6. Pathogen source and route of invasion: The source of the pathogen of hospital-acquired pulmonary infection and the route of invasion are as follows:

(1) Contaminated air aerosol inhalation: The hospital is a polluted environment. The distribution of therapeutic microorganisms is extremely extensive, and it is easy to cause air pollution. A large number of airborne aerosols containing pathogens are formed. This aerosol is in the air for a long time. Floating, once inhaled by susceptible patients, can cause lung infections. The sources of common contaminated aerosols are as follows:

1 Patient's droplet nucleus and dust: Patients with respiratory infections will discharge a large amount of droplets containing pathogenic microorganisms when coughing or sneezing (1 × 105 droplets can be produced by one sneeze), and the droplets are dried to form The droplet core can be suspended in the air for a long time. The droplets with a diameter larger than 100m can quickly settle on the surface of the object. After drying, it forms a dust with the pathogens of other sources and resuspend in the air. Some infectious and resistant. Dry pathogens such as Mycobacterium tuberculosis, Staphylococcus aureus, Streptococcus pneumoniae and Legionella, measles and influenza viruses, and Mycoplasma pneumoniae can be transmitted in this way. Gram-negative bacilli such as Pseudomonas aeruginosa have also been introduced in recent years. Reported by the bacteria-containing aerosol, in 1992, Kleemola reported an outbreak of Mycoplasma pneumoniae infection in the emergency department of the Kuopio University Hospital in Finland. Among all 97 employees, 2 had mycoplasma pneumonia and 66 had fever. And upper respiratory tract infections such as sore throat, cough, headache and joint pain, etc. In 1994, Millar reported the drug-resistant Streptococcus pneumoniae (serology type 9) Streptococcus pneumoniae outbreak in a hospital people, secondary infections are caused by inhalation of aerosol droplets.

2 iatrogenic pollution of the instrument: In recent years, ventilators, humidifiers, nebulizers and pulmonary function testers have been widely used in clinical practice, and the resulting instrument contamination has become an important cause of hospital acquired pneumonia. Because of the large amount of aerosol generated by this pollution, it is directly contacted with the patient, so it can not only directly affect the patient being treated, but also indirectly affect the same patient or a wider range of patients, resulting in an outbreak of infection, resulting in an outbreak of infection. There are many reasons for the pollution of the instrument, mainly water pollution, contact pollution and disinfectant pollution.

Clinically, when using nebulizer, humidifier, oxygen flow meter and ventilator, sterilized distilled water should be used as required. When adding liquid, try to avoid the intrusion of pathogenic microorganisms. The treatment solution should be prepared temporarily. The pipeline system should be regularly. Disinfection, it is strictly forbidden to treat two patients at the same time with one machine. If the operation regulations are violated, the above instruments are highly polluted during use. Some hydrophilic Gram-negative bacilli such as Pseudomonas aeruginosa, Escherichia coli, Serratia, Klebsiella, Flavobacterium and Legionella can be rapidly propagated in water. When the contaminated instrument is used again, the large amount of aerosol contained in the bacteria can cause hospitalic lungs once inhaled by the patient. Department of infection.

Ventilator pollution has become an important concern at present. According to the US CDC, patients who continue to use mechanically assisted breathing are 6 to 12 times more likely to develop nosocomial pneumonia than those who do not. Fagon et al. The risk can be increased by 1% every day. In addition to the patient's own immunity, tracheotomy, tracheal intubation and sucking injury, the pollution of mechanical ventilation itself is also an important factor. The ventilator is often susceptible to contamination. With the patient's tracheal intubation interface, Y-shaped tube, nebulizer and condensate in the pipeline, Graven et al reported that after using the ventilator 2 hours, 33% of the inspiratory tube can be infected by bacteria in the oropharynx, up to 24h The pollution rate can reach 80%. Generally speaking, the closer to the patient end, the more serious the pollution. Some people take liquid culture from the condensed water and found that 80% of the bacteria grow, the average is 2 × 105 / ml, from the air around the ventilator. The bacteria cultured in the stomach are basically the same as the pathogens in the patient's respiratory tract, suggesting that the ventilator contamination cannot be ignored. Because the ventilator piping system is contaminated, the patient is moved, nasal feeding, sucking and adjusting the position of the ventilator. It is often necessary to move the pipeline. If it is slightly careless, it is easy to directly inject the condensed water containing bacteria into the lower respiratory tract of the patient, causing repeated iatrogenic infection. On the other hand, the bacteria in the pipeline are ventilated at high speed in the ventilator. Under impact, a bacteria-containing aerosol can also be formed and blown into the distal airway and lung parenchyma. The bacteria in the tracheal intubation can often be integrated into a biofilm, which is sucking, changing tubes and performing fiberoptic bronchoscopy. When examined, once shedding, it can also cause localized atelectasis, focal pneumonia and lung abscess.

In addition, clinically used anesthesia resuscitation bags, simple respirators, etc. are often contaminated by the patient's secretions. During use, the bacteria remaining in the memory can enter the body with the airflow, and contaminated by pollutants and disinfectants also cause hospital-acquired lungs. The important reasons for infection are not to be ignored.

3 Environmental pollution: In recent years, hospitals with better conditions have used air-conditioning systems. Some hydrophilic pathogens such as Legionella can survive in water for more than 1 year. When the water source is at 25-42 ° C, there is a little scale and precipitation and relative When it is stationary, once it is contaminated by Legionella, it can be multiplied, causing pollution in air conditioners, cooling towers, showers and faucets. The large amount of bacteria-containing aerosols generated during air-conditioning use can cause an outbreak of lung infection in hospitals.

Fungi are also an important source of infection. In the humid environment of the hospital, there are a large number of fungi growing in indoor objects, utensil surfaces, house surfaces and ventilation ducts. The spores can be suspended in the air for a long time. Susceptible patients inhaled into the lungs are likely to cause lung infections. The more common fungi in the clinic are Candida albicans, Aspergillus spp. and Mucor.

(2) Oropharynx secretions and esophageal reflux fluid aspiration: the source of the aspirate is mainly the secretion of the oropharynx and the reflux of the upper digestive tract. Under normal circumstances, the pH of the gastric juice is <2, and the bacteria are difficult to be in it. Colonization and survival, if the pH rises above 4, the bacteria can multiply in the gastric juice and colonize the stomach wall. This situation is more common in the elderly, heavy drinking, long-term nasal feeding, use of antacids and H2 receptor resistance Diarrhea, duodenal juice, gastric reflux and decreased gastric motility, etc., and the long-term placement of the nasal feeding tube not only helps the bacteria to adhere to the surface, but also a large number of bacteria that can be propagated in the stomach can move along the wall of the nasogastric tube. .

In addition to aspiration factors, in the tracheal intubation, tracheotomy, suction and fiberoptic bronchoscopy, if improperly operated, not only easy to damage the airway mucosa, destroy its barrier function and mucociliary carrying capacity, but also often Bacteria in the oropharynx, nasal cavity or outside are brought into the lower respiratory tract. The pathogens that are brought in are mostly pathogenic bacteria, and bypass the normal physical and biological barriers and killing effects of the body, causing artificial lower respiratory tract organisms. Vaccination.

The aspirate liquid often contains a large number of Gram-negative bacilli, Gram-positive cocci and anaerobic bacteria, aerobic bacteria and anaerobic bacteria can cooperate with each other in lower respiratory tract infections. On the one hand, the growth and reproduction of aerobic bacteria provide organs for anaerobic bacteria. The redox potential environment necessary for growth, on the other hand, anaerobic bacteria can also interfere with the body's phagocytosis and killing of aerobic bacteria, leading to serious mixed infection.

After the pathogen enters the lower respiratory tract, it first adheres to the respiratory mucosa or mucosal damage by its specific structure on the surface to complete its colonization. These surface structures include bacterial pili, colonization factors and mucin, viral spines, glycolipids. Proteins and parietal acids, etc., which can be specifically linked to the corresponding receptors of the respiratory epithelium. Once the colonization ability of the trachea is reduced, such as airway mucosal cilia function is impaired, the airway mucosa is caused by poor ventilation during mechanical ventilation or oxygen inhalation. Excessive dryness, retention, decreased cough reflex or decreased systemic immune function, colonized bacteria can multiply and secrete various enzymes and biologically active substances such as proteolytic enzymes, phospholipases, hyaluronidase, collagenase, liver The enzymes and internal and exotoxin cause a series of pathological damages such as airway mucosa and pulmonary parenchyma edema, hemorrhage, exudation and tissue necrosis.

(3) The spread of local lesions and the metastasis of distant lesions: the spread of local lesions and the metastasis of distant lesions mainly cause self-infection in the hospital, which is common in thoracic and abdominal surgery, bloated, empyema, esophagitis, mediastinal lesions, Underarm abscess, intestinal infection, burns and sepsis sepsis, although this proportion of infection is not large, but the condition is quite dangerous, often life-threatening.

In recent years, when the body's immune function defects (such as AIDS), the use of immunosuppressive agents, severe trauma and burns, etc., often cause unexplained intestinal bacterial lung infection, recently confirmed by radionuclide tracer method, Intestinal Escherichia coli can enter the blood circulation through the apical and basal lesions of the small intestine villi in severe burns, and then migrate to the lungs to cause self-infectious nosocomial pneumonia. Unexplained lung infections should take into account the possibility of enterogenous infections.

Whether the above factors cause lung infection depends on the quantity and intensity of pathogenic microorganisms on the one hand, and on the other hand, it is easy to be related to the patient's disease resistance. In summary, the pathogen can enter the upper respiratory tract through various routes, firstly completed. The colonization of the respiratory mucosa, then began to multiply when the conditions are ripe, causing a series of pathological damage to the lung parenchyma.

Elderly patients with acquired pneumonia prevention

Primary prevention

Also known as etiological prevention, this stage of the disease has not occurred, but risk factors already exist, such as critical illness of the patient such as liver, brain and kidney and other important organ failure, weak body resistance, advanced age, mental stimulation, low mood, etc. There are infection sources such as respiratory system, digestive system, and urinary tract infections. This level of prevention can be divided into promoting health and special protection.

(1) Promote health and actively treat primary diseases: carry out health education, pay attention to reasonable nutrition, and reduce digestive system function in the elderly. Therefore, elderly patients should be fed a nutritious and digestible diet, and medical staff and their families should be more elderly. Conversation, comfort and encouragement are the patient's confidence in fighting the disease, maintaining an optimistic attitude and preventing the invasion of pathogens.

(2) Special protection:

1 Strict management of patients, pathogens and control of environmental pollution: patients with hospital-acquired pulmonary infections and pathogens do not have obvious contagiousness, so the general hospital does not require isolation treatment for most of these patients, but According to foreign literature reports, such as mycoplasma pneumonia and drug-resistant streptococcus pneumonia and other diseases have occurred in the outbreak of nosocomial infections, one of the measures to treat patients is relatively concentrated treatment, in the conditional hospitals, the following pathogen infection is best relative isolation treatment: Influenza virus, respiratory syncytial virus, Legionella, mycoplasma, drug-resistant Staphylococcus aureus, Streptococcus and Pseudomonas aeruginosa, etc., and other patients who are admitted to the pathogen, family members and patients in the incubation period should also be isolated. To prevent cross-infection, and to monitor the suspected water source and air-conditioning system, so as to prevent the outbreak of infection.

2 The route of transmission of the infection is cut off: As mentioned above, the disease is mainly transmitted by air and droplets. In addition, it can be caused by various methods such as contact and interventional operation. The clinical work should be prevented according to the specific situation. Such as air disinfection, strengthen airway management, carefully perform various operations, thoroughly wash hands and properly handle patient secretions, etc., conditional units should use air filtration and purification devices.

3 protection of susceptible patients: the elderly are susceptible to hospital-acquired pneumonia, should be protected according to specific circumstances, in principle, the ward should be regularly ventilated, disinfected, patients should try to live in the small ward, and strictly close contact between patients, All kinds of operations should be gentle, the drugs should be applied reasonably, the diet should be rich in nutrients and easy to digest and absorb, if necessary, use immunopotentiators to improve the patient's immunity.

2. Secondary prevention

This prevention mainly includes early detection and timely treatment.

(1) Early detection: elderly hospitalized patients are high-risk groups with pneumonia in the hospital. They should be carefully observed and regularly checked. If there is fatigue, general discomfort, anorexia or mild cough on the basis of the original disease, physical examination should be performed. And laboratory tests to detect early infections in the lungs.

(2) Timely treatment: Once hospital-acquired pneumonia is found, it should be treated promptly, given effective antibiotics, treated according to different pathogens, treated with anti-virus or antibiotics and anti-fungal drugs, timely control of disease, prevention of disease changes and avoiding concurrent The occurrence of the disease.

3. Three levels of prevention

Also known as clinical prevention, it is mainly to use a variety of clinical methods to make pneumonia recover soon and reduce the adverse consequences caused by the disease. Old hospital acquired pneumonia can be combined with some complications, and it is extremely important to actively treat these complications.

1 respiratory failure: a higher incidence, strengthen oxygen therapy, if necessary, ventilator treatment, if still do not improve can consider tracheal intubation, mechanical ventilation;

2 heart failure is one of the main causes of death from pneumonia. Once heart failure occurs, give heart and diuretic treatment immediately;

3 arrhythmia: anti-arrhythmia drugs can be selected according to different types of heart rhythm; correcting water and electrolyte disorders is also extremely important;

4 shock: more common in hypovolemic shock and septic shock, supplement blood volume, rational use of vasoactive drugs.

Acquired pneumonia complications in the elderly Complications, respiratory failure, heart failure, pulmonary edema, arrhythmia, pulmonary encephalopathy, shock, acute myocardial infarction, pleurisy, empyema

There are many complications of pneumonia, such as respiratory failure, heart failure, pulmonary edema, arrhythmia, respiratory acidosis, pulmonary encephalopathy, gastrointestinal bleeding, hydroelectric medium disorder, shock, acute myocardial infarction, followed by pleurisy, empyema and so on.

Symptoms of acquired pneumonia in the elderly. Common symptoms Chest pain, fatigue, nasal congestion, chest tightness, cough, reflex, loss of appetite, sleepiness, weightlessness, and impotence

Viral pneumonia

In general, the incidence of winter and spring, mostly between November and March to April, slightly later than the outbreak of viral infection outside the hospital, patients with viral respiratory infections as the main source of infection, early patients with fatigue, general malaise and appetite Decreased, generally no fever, local symptoms are mostly catarrhal symptoms of the nasopharynx, such as nasal mucosa congestion, nasal congestion after edema, etc., with the development of the disease can invade the lung parenchyma and pulmonary interstitium, showing cough, mostly Paroxysmal dry cough, shortness of breath, chest pain, fever, in addition to the general performance of the above pneumonia, some patients have persistent high fever, severe cough, blood stasis, palpitations, dyspnea and cyanosis, and can occur ARDS, heart failure and acute renal function Depletion, even shock, early lung examination, the lungs can be normal, there may be mild signs such as mild lung dullness in the percussion, auscultation of respiratory sounds weakened and scattered dry, wet voice, aggravation of the lungs, auscultation of the lungs It can smell a wide range of wet voices and wheezing sounds, and there are few signs of consolidation.

2. Bacterial lung infection

Hospital-acquired pulmonary infections are mostly caused by Gram-negative bacilli. Because of the unspecificity of the symptoms and the diversity of pathogens, the onset of the disease is often insidious. The patient's performance at the beginning of the disease is apathy, lethargy, fatigue, shortness of breath and chest discomfort. Such symptoms, normal or slightly elevated body temperature, relatively slow pulse, about half of patients may have cough, cough and other respiratory symptoms, most of which are yellow purulent, Pseudomonas aeruginosa infection can cough green or Yellow purulent; Klebsiella pneumoniae sputum viscous, some may be brick red jelly, a small number of patients with hemoptysis; Escherichia coli infection, more sputum, odor, mostly white or yellow sticky; sand Lei-bacteria infection can occur "pseudo-hemoptysis" phenomenon, which is caused by red pigment produced by some strains. If the lesion develops further, the condition can rapidly deteriorate, and some patients turn into pulmonary septic pleurisy, sepsis and toxic shock. High fever can occur, sputum is sticky and difficult to cough up, unconsciousness, anemia, systemic failure, difficulty breathing and blood pressure drop, eventually dying from breathing, circulatory failure, death The rate can be as high as 60%. The auscultation can be heard and scattered in the lungs. The small blisters are more common in the bottom of the lungs, and can also smell dry voices. The sounds of the late lesions can be more extensive, often with humming sounds. Lord, about 20% of patients can not smell the lungs, it is generally difficult to see signs of lung consolidation, the Department of Legionella pneumonia in the hospital more concentrated onset, patients at the beginning of the disease may have discomfort, myalgia, chest pain, dry cough and low fever, etc. With flu-like symptoms, a small number of patients have a small amount of sputum or a small amount of blood in the sputum. After 1 to 2 days of onset, the condition can rapidly deteriorate, and there is high fever, mental confusion, abdominal pain, diarrhea, vomiting and difficulty breathing. The lungs can smell and sputum. Some patients may involve the pleura. According to statistics, Legionella pneumonia accounts for about 14% of hospital-acquired pulmonary sensation infections, and mortality accounts for 3.8% to 6.6%. After long-term bed rest, chest and abdomen surgery, tracheal insertion In patients such as tube, due to the large amount of sputum after bacterial infection, the airway mucus is complicated and the cilia carrier system is dysfunctional, and the cough reflex is weakened. It is often prone to sputum drainage, resulting in sudden onset of atelectasis. For continued Dyspnea, respiratory rate, inspiratory three depressions and hypoxemia, physical examination can be found in the disappearance of mediastinal shift to the affected side ipsilateral lung and breath sounds and so on.

In recent years, hospital-acquired anaerobic pulmonary infection has received widespread attention. Anaerobic infections often occur in tracheal intubation, long-term nasal feeding, unconsciousness and medullary paralysis, mainly due to aspiration. Because the mouth contains a large number of anaerobic bacteria such as Clostridium, Fusobacterium and anaerobic streptococci, once aspiration, it is easy to cause lung anaerobic infection, the study found that the hospital acquired infection caused by obvious aspiration The anaerobic bacteria can be detected in more than 30% of the airway secretions sucked out by the airway. This suggests that the incidence of lung infection caused by anaerobic bacteria is actually much higher than the current clinical statistics, anaerobic lungs. Most of the infections are mixed with secondary or pulmonary aerobic infections. After Gram-negative bacilli infection, the lung parenchyma is degenerated, necrotic, local oxygen consumption, and redox potential is reduced. At this time, anaerobic bacteria can take advantage of it. , mass reproduction, further damage to the lung parenchyma, leading to focal lung suppuration, in patients with obvious symptoms of infection, such as fever, fatigue, weight loss, sweating, anemia and clubbing of unknown cause, etc. Cough yellow purulent sputum, may have necrotic tissue, odor evident, the condition is easy to delayed healing, from the ventilator is very difficult.

3. Fungal pneumonia

Often secondary to bacterial pneumonia, viral pneumonia and tuberculosis and other diseases, mostly secondary infections, patients with long-term application of broad-spectrum antibiotics and a large number of hormones, the history of immunosuppressive agents, common fungi have Candida albicans, Aspergillus, followed by Mucor, Cryptococcus neoformans, Nocardia and actinomycetes, even visible histoplasma, fungal lung infection mainly manifested as allergic symptoms and inflammation, lack of specificity before symptoms, easy to be Covered by the disease, those who are susceptible to hospitalization, once the body temperature, sputum volume, sputum traits and primary lung disease are cured, the new inflammatory lesions in the chest X-ray should consider the possibility of pulmonary fungal infection.

The above are the typical symptoms and signs of acquired pneumonia in the elderly, but most patients lack the above typical symptoms and signs, non-respiratory symptoms are sometimes prominent, such as apathy, disturbance of consciousness, feeling slow, mental disorders and other neurological symptoms, easy to old age Dementia, senile psychosis mixed; gastrointestinal infections, urinary tract infections can cause pneumonia through bacteremia; can make clinical symptoms complex, such as vomiting, diarrhea, etc., lung infections are mostly in chronic bronchitis, obstruction On the basis of onset of emphysema, it is often caused by inhalation; cough is also mild or not coughing at all, coughing, or convulsions, coughing, etc., dyspnea and respiratory failure are prominent, and the physiological decline of respiratory organs in the elderly is obvious. In addition to repeated lung infections, lung function is significantly reduced, and when acute lung infection occurs, it often causes failure, especially the patient's original chronic bronchitis, obstructive emphysema, pulmonary heart disease, clinical manifestations of dyspnea It is progressively aggravated, and there is no dullness and snoring in the early chest. It can be heard when breathing deeply; sometimes it is the only sign of the whole disease. Physical signs are mostly limited to the bottom of the lungs. There are localized voiced sounds, bronchial breath sounds and moderate voices. Usually, physical examination is not serious or misunderstood as chronic bronchitis and signs of emphysema.

Clinical features: Aged hospital acquired pneumonia is a group of lower respiratory tract infections caused by various pathogens during hospitalization. Due to the variety of pathogens, the patients have more primary diseases, different pathogenesis and scattered lesions. The disease is overlapped with the acquired lung infection in the hospital, covering up, and the pathogens of different pathogens are simultaneously or alternately diseased, which complicates and diversifies the clinical manifestations of the disease. It has the following characteristics: 1 The symptoms are not typical, and the diversity is easy. Repeatedly, often conceal and overlap with the symptoms of the underlying disease; 2 insidious onset, polydisperse onset, occasional outbreaks in the hospital; more than 3 infancy, immune function defects, taking a large number of hormones, immunosuppressants and tracheal intubation , tracheotomy mechanical ventilation, chest and abdomen surgery, coma and general anesthesia patients; 4 general condition, rapid progress, easy to deteriorate, can be quickly converted into severe pneumonia, sepsis and infection toxic shock, high mortality; 5 lesions scattered The lower leaves are more common, the lungs are rare, and the signs are not obvious; more than 6 are resistant strains, multiple senses Common and difficult to treat condition can be improved with the recovery base lesions.

Examination of acquired pneumonia in the elderly

1. Laboratory testing of pathogens

(1) Due to the limitations of the conditions, this method is the main method of collecting specimens. Therefore, before taking the specimens, use normal saline or hydrogen peroxide to gargle. Pay attention to coughing deep sputum as much as possible, which can significantly reduce the contamination of oral pathogens and improve the reliability of detection. Sexual, bronchoscopy, for patients with existing tracheal intubation, tracheal attraction through the fiberoptic bronchoscope is more convenient, because the fiberoptic bronchoscope must pass the oropharynx or tracheal intubation site with a bacterial colonization rate of 90% Therefore, the aspirate is extremely polluted. In order to avoid the pollution, there are two techniques available. One of the technologies is a protective brush. This method needs to effectively obtain uncontaminated under the X-shaped indication. Respiratory specimens with a sensitivity of 75%, another method is protective alveolar lavage, collecting lavage fluid for bacteriological examination, the sensitivity is up to 86%, using sterile containers to retain specimens Must be sent immediately after inspection, first microscopic examination, observe the shape, type and quantity of cells, columnar epithelium and its cilia damage, cell types or distribution of cells within the cell, distribution and quantity, with or without capsules and flagella, with or without Hyphae and spores, such as specimens taken from the lower respiratory tract, microscopic examination is the classification of the rapid identification of bacteria, obtaining preliminary diagnosis and guiding clinical treatment is still of great significance, in addition to sputum specimens, in addition to microscopic examination, bacterial culture should be carried out as soon as possible After cultivation, it is characterized by the characteristics of the colony of the bacteria, the characteristics of pigments, biochemistry and exercise tests. In the clinical examination, a large number of bacteria may be found in the smear during the smear examination, while the sterile culture is usually grown during the culture. This suggests that we have two possibilities: one is that the pathogen is an anaerobic bacterium; the other is that the patient has used antibiotics, inhibiting the growth and reproduction of the bacteria, and clinically considering the patient as an anaerobic pulmonary infection, the conventional method of sputum examination It is difficult to be effective. If necessary, the specimen can be taken by percutaneous lung puncture or blood is taken for culture diagnosis.

(2) Blood culture plays an important role in hospital acquired pneumonia. A considerable number of patients have bacteremia. Therefore, blood samples can be collected for culture before the use of antibiotics or during the chills and fever. .

(3) Serological test: mainly used for virus diagnosis. Different viruses can be used in different methods. Influenza virus can be diagnosed by hemagglutination inhibition test, complement binding test and ELISA method, and respiratory secretions can be taken when cytomegalovirus infection occurs. Tissue specimens are inoculated into human embryonic fibroblastic medium, which can be isolated from cytomegalovirus. It can also be diagnosed by examining cytomegalovirus. Measles virus can detect serum specific IgM antibody as an early diagnosis by serum. Complement binding test is also helpful for diagnosis when double serum titers are more than 4 times higher; respiratory syncytial virus can be detected by ELISA with a positive rate of 85% to 90%, and monoclonal bridge membrane enzyme labeling method can also be used. Detection.

2. General inspection

In some patients, the total number of white blood cells increased more than 10 × 109 / L classification of neutrophils, but the majority of elderly patients did not increase the total number of white blood cells, neutrophil classification is normal or decreased, the change has no specific specificity, ESR mostly increased .

3. X-ray chest

It is extremely important for the diagnosis of acquired pneumonia in the elderly. The chest X-ray shows that the lesions occur in both lungs, the inner, middle, bronchial and peripheral interstitial inflammation of the lower field, which is characterized by increased lung texture, thickening and blurring. Sexual exudation and consolidation, which are characterized by fuzzy patch shadows distributed along the lung texture, uneven density, dense lesions can be fused into larger lobes, and may involve multiple lobes, but in the early stages of the disease, especially patients In the case of dehydration or leukopenia, the chest radiograph may be normal, usually after correction for dehydration for 24h, a new infiltrating lesion can be seen on the chest radiograph.

4. Lung CT

CT examination plays an important role in the diagnosis of hospital-acquired pulmonary infections, especially in patients with bone marrow, organ transplantation and the elderly. CT can often detect lesions early. CT images of bacterial lung infections are mainly represented by two lung basal segments. Multifocal inflammatory lesions, lesions are mostly patchy, nodular, blocky and irregular images, some lesions can be fused to each other, there are small hollow or honeycomb changes, and bronchiectasis images can also be seen when In the case of fungal pneumonia, CT images are mainly characterized by single or multiple villous inflammatory masses, nodules and halo signs, surrounded by low-density areas, CT values are lower than the center of the lesion, but higher than normal lung CT values. .

Diagnosis and identification of acquired pneumonia in the elderly

diagnosis

According to the atypical clinical symptoms, the disease is serious, the progress is fast, the deterioration of the bureau, plus auxiliary examination, bacterial culture, X-ray performance, general clinical diagnosis is not difficult.

Differential diagnosis

Heart failure

In the early stage of left heart failure, there is cough, cough foaming, difficulty in breathing, and it is not easy to lie down. The wet sounds of both lungs are more extensive and can change with body position.

2. Lung cancer with obstructive pneumonia

If the effect of adequate antibiotic treatment is not satisfactory or the nature of the intrapulmonary shadow is unknown, it should be used for the diagnosis of exfoliated cells, carcinoembryonic antigen, X-ray film, CT and fiberoptic bronchoscopy.

3. Tuberculosis

Older pulmonary tuberculosis often lacks typical symptoms, signs and X-ray findings. The cause of fever is unknown. X-rays have obvious shadows. Generally, those with poor anti-infection effects should consider the possibility of tuberculosis. Carefully trace the history, X-ray film on the old tuberculosis The presence and examination of acid-fast bacilli are helpful for diagnosis.

4. Pulmonary embolism

There are surgery, trauma, heart disease (especially with atrial fibrillation) and history of phlebitis, manifested as sudden dyspnea, cough, hemoptysis and chest pain, typical changes in ECG help to identify.

5. Other

Patients with gastrointestinal symptoms should be differentiated from acute gastroenteritis and acute abdomen; shock pneumonia should be differentiated from cerebrovascular accident and shock caused by it.

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