Positive bacillus pneumonia in the elderly
Introduction
Introduction to elderly positive bacillus pneumonia Gram-positive bacilli pneumonia is caused by Gram-positive bacilli infection, because the immune function of the elderly is particularly susceptible to Gram-positive bacilli pneumonia, followed by newborns, pregnant women and other patients, clinical manifestations, sudden onset, chills, high fever. Difficulty breathing, high mortality, lung anthrax is one of the common diseases. basic knowledge Sickness ratio: 12% Susceptible people: the elderly Mode of infection: respiratory transmission Complications: sepsis meningitis shock
Cause
The cause of elderly positive bacilli pneumonia
(1) Causes of the disease
Gram-positive bacilli include Bacillus, Listeria, Corynebacterium and Erysipelas. Except for a few pathogenic bacteria, most Gram-positive bacilli are non-pathogenic bacteria, Bacillus subtilis and Bacillus subtilis Bacillus cereus, widely distributed in dust, water and air, is basically not pathogenic, among which Bacillus anthracis can cause pulmonary anthrax, which is relatively rare, and the production of Listeria monocytogenes is neonatal and immune. Low-function patients with meningitis, an important pathogen of sepsis, almost no reports of pulmonary infection, except for the diphtheria bacilli, commonly known as Corynebacterium diphtheria, including Corynebacterium pseudotuberculosis, Corynebacterium dry and Corynebacterium diphtheriae Species, oropharynx or normal skin flora, except for patients with low immune function, rarely cause disease, but recent reports on coryneform bacteria, especially JK group, causing sepsis, infective endocarditis and venous cannula infection, worthy of It is important to note that erysipelas and lactobacilli are generally considered to be non-pathogenic bacteria, occasionally causing lung infections and sepsis.
Bacillus anthracis: Gram-positive bacilli, aerobic facultative anaerobic, large bacterial cells, 4 to 8 m long, no flagella, no motility, spore formation under adverse conditions, good growth in common medium, strong resistance (survived in fur for several years), boiled for 40 minutes, dry heat 140 ° C for 3 h, 110 ° C high pressure steam for 10 min, 100 ° C flowing steam for 60 min, formaldehyde solution soaked for 15 min to die, the breeding of Bacillus anthracis can secrete anthrax toxin, the toxin is Complex multimer, composed of edema factor, protective antigen, and necrosis factor.
(two) pathogenesis
Pulmonary anthrax is characterized by hemorrhagic bronchitis, bronchial pneumonia, pulmonary infarction, and often accompanied by high enlargement of the hilar and mediastinal lymph nodes, hemorrhagic infiltration, pleural effusion is often involved, if the invasive Bacillus anthracis is small or low in toxicity, The human body may not develop disease, form a recessive infection, and the number of spores is increased. The phagocytic cells are introduced into the local lymph nodes, and are released into the blood circulation after mass reproduction to form sepsis. The anthrax toxin directly damages the capillary endothelial cells, and the inflammatory medium is released. Clinical severe symptoms of poisoning, respiratory and respiratory failure.
Prevention
Elderly positive bacillus pneumonia prevention
1. When the environment is not cured, the treatment should be isolated. The patient room should reduce the flow of people, pay attention to the cold and keep warm during the epidemic, and try to stay away from the crowded public places.
2. Improve the state of hypoxia. It can be used for home oxygen therapy, oral administration of sputum drugs, and more water diversion to moisturize sputum, which is good for sputum excretion.
3. Strengthen functional exercise, increase nutritional support, and give immune enhancers.
Complication
Elderly positive bacillus pneumonia complications Complications sepsis meningitis shock
Common sepsis, meningitis, shock, respiratory and circulatory failure.
Symptom
Elderly positive bacillus pneumonia symptoms common symptoms cyanosis high fever circulatory failure dyspnea chest pain chills vocal edema
1. Primary inhaled pulmonary anthrax is the most common, a few secondary to skin anthrax, the incubation period is 1 to 7 days, usually 2 to 3 days, sudden onset, acute onset, or 2 to 4 days of flu-like Symptoms, sudden onset after remission.
2. Clinical manifestations include chills, high fever, difficulty in breathing, chest pain, hemoptysis, cyanosis, wet sputum in the lungs, subcutaneous edema in the neck and chest, signs are relatively light, and the severity of the disease is asymmetrical. The treatment was not timely, and most died in respiratory failure after 24 to 48 hours.
3. The skin sees necrosis, ulceration, and characteristic charcoal-like additions, which are typical changes.
Examine
Examination of elderly positive bacilli pneumonia
Blood routine
Peripheral blood leukocytes in patients with anthrax were significantly increased, generally (10 ~ 20) × 109 / L, up to (60 ~ 80) × 109 / L, classified neutrophils increased.
2. Bacteriology examination
The diagnosis relies on direct smear examination or culture from wound secretions, skin eschar, sputum, blood, vomit, feces and cerebrospinal fluid to isolate Bacillus anthracis.
(1) Direct smear examination: specimens of infected parts such as blister fluid of patients with skin anthrax, sputum of patients with pulmonary anthrax, diarrhea or vomit of patients with intestinal anthrax, cerebrospinal fluid of meningitis patients, smear, Gram stain, see A typical diagnosis can be made by combining Bacillus anthracis with clinical manifestations. Anthrax spores can be confirmed under the microscope after staining with methyl blue or Indian ink.
(2) Identification of bacterial culture: The positive rate of blood culture is high, but the positive rate of skin lesions is 60%-80%, the positive rate of nasopharyngeal swab culture is lower, and B. anthracis forms long chain or flocculation in broth culture medium. The growth of the precipitate was observed. On the blood plate, no hemolysis, gray, and coarse colonies were formed after 24 hours at 37 ° C. The colonies were observed to have curls under low magnification.
1 Bead test: B. anthracis in morphological changes in 0.05-0.1 U/ml penicillin medium, beaded into a spherical spheroid, connected like a rosary, and the anthrax did not react.
2 bicarbonate virulence test positive: the test bacteria were inoculated on a 0.5% sodium bicarbonate agar plate, placed in a 10% carbon dioxide environment at 37 ° C for 24 ~ 48h, the toxic strain formed a capsule, showing a mucus type; The toxic strain does not form a capsule, is a rough colony, and has clinical reports of resistance to penicillin, so it is necessary to conduct drug susceptibility experiments on cultured colonies, especially for bioterrorism-related anthrax cases.
(3) Serological examination: Serological diagnosis is of little value, generally used for epidemiological investigations, such as enzyme-linked immunosorbent assay for spore antigens, such as antibody titer is increased by 4 times, suggesting that it has been infected or vaccinated recently. An enzyme-linked immunoelectrophoresis assay or an indirect hemagglutination assay for protective antibodies can also be used to aid diagnosis.
(4) Molecular biological examination: polymerase chain reaction (PCR) specifically amplifies Bacillus anthracis or anthrax spore specific markers, which can be used for diagnosis, and can also be used for typing, assisting in judging the source of infection, and the main target of PCR diagnosis. The gene is a gene encoding a virulence factor, the toxin genes (pagA, lef, and cya) are encoded by the virulence plasmid pXO1, and the biosynthesis of the capsule (capB, capC, and capA) is encoded by pXO2, and these virulence genes are Bacillus anthracis Peculiar, therefore, plasmid-based assays are highly specific. However, it has also been reported that certain charcoal stem strains lack these plasmids. Therefore, a method for detecting specific positions on chromosomes to detect non-toxic and plasmid-containing anthrax has been developed. Bacillus is very necessary. Recently, Qi et al. developed a fluorescence resonance energy transfer PCR method for the rpoB gene on the chromosomal localization of Bacillus anthracis. This method seems to be the most specific to date, among 175 non-Bacillus anthracis specimens. Only 1 case was reported as positive, with primer and probe combinations: BA1 for one site in pXO2, BA2 for pXO1, and BA3 for a site on the chromosome of Bacillus anthracis
3. X-ray examination showed that the lungs were infiltrated, the mediastinum was widened, and the pleural effusion was observed.
Diagnosis
Diagnosis and identification of elderly positive bacilli pneumonia
In the epidemic area, the diagnosis is easier, and the sporadic diagnosis is difficult. The gram-negative gram-positive bacilli can be seen in the secretion smear of the sputum, and the sputum culture can be clearly diagnosed.
Differential diagnosis
1. Skin anthrax must be distinguished from skin damage caused by other causes such as cellulitis caused by Staphylococcus aureus, sputum, etc., generally have obvious swelling and pain without eschar; skin damage caused by vaccinia and skin anthrax Very similar, but often painful; sheep smallpox (sheep contact with infectious deep pustules) and milking human nodules are caused by parapoxvirus infection, the source of infection is sheep and cattle, generally no edema, and Vaccination can also produce similar skin lesions. Patients have a recent history of vaccination, which usually occurs in patients with T cell defects. Ascariasis due to bite is also anxious, not painful, and there is lymph node swelling nearby. However, the skin lesions are generally located in hidden parts such as the groin, underarms, perineum, and external genitalia. The pathogen examination of the blister or ulcer can be confirmed.
2. Pulmonary anthrax is similar to general upper respiratory tract infection in the early stage, and dyspnea should be distinguished from infectious atypical pneumonia, leptospirosis, and pneumonic plague. It is often identified by epidemiological characteristics and pathogenic diagnosis.
3. Intestinal anthrax is clinically dysentery, typhoid or Yersin enteritis, sometimes as acute abdomen, but its toxemia symptoms are obvious, stool or vomit culture results can help identify.
4. Anthrax meningitis must be differentiated from cerebrovascular accidents, meningitis caused by other pathogens, and cough smears of the cerebrospinal fluid can be confirmed by the thick bamboo-like anthrax.
5. Anthrax sepsis should be distinguished from sepsis caused by other bacteria, and pathogen examination can help to confirm the diagnosis.
