Pneumocystis
Introduction
Introduction to pulmonary coccidioidomycosis Coccidioidomycosis is a fungal disease of the lungs or other organs caused by Coccidioides. The lung is the invasive portal of coccidioides and the most commonly involved organ. The clinical classification is primary and progressive, the primary is acute, self-limiting respiratory infection; the progressive manifestation is chronic, often fatal systemic infection. basic knowledge The proportion of illness: 0.0005%, found in people with low physical fitness Susceptible people: no special people Mode of infection: contagious Complications: hemoptysis
Cause
Cause of pulmonary coccidioidomycosis
Causes:
Coccidioides is a biphasic fungus, which is a joint mycelium in nature, and forms a spore type of small spheres in the host body. It is propagated by forming endospores in mature pellets. The bacteria are dry, sunlight, ultraviolet rays. It is more tolerant and sensitive to formaldehyde. It is usually killed at 60 ° C for 1 h.
Pathogenesis:
After being inhaled into the respiratory tract, the mycelium of the globospores multiplies in the alveoli, producing a large number of spores, which cause an acute inflammatory reaction mainly caused by neutrophils. During the process of spore development and formation of endospores, the tissue reaction gradually becomes acute. Suppurative inflammation transitions to chronic granuloma. The immunity to coccidioides is mainly cellular immunity. The cellular immune response of the host is not complete for the killing of coccidioides. The performance of the disease caused by coccidioides is related to the immune status of the host. Decreased immunity or inhibition causes coccidioides to invade, parasitize and multiply and cause disease. It is reported that some races (black race, American Indian, etc.) and certain blood types (type B, AB) are more susceptible to infection. Or cause systemic spread.
The histopathological changes of sporozoites alternated between suppurative inflammation and granuloma, and different tissue responses were observed at the same site at different stages.
Prevention
Pneumococcal disease prevention
Avoiding entry into endemic areas is an effective way to prevent this disease.
Complication
Pneumococcal disease complications Complications hemoptysis
There are three potential complications of Pneumocystis cavity:
1. Secondary bacterial or other fungal infections.
2. The cavity is broken.
3. Fatal hemoptysis.
Symptom
Pneumococcal disease symptoms Common symptoms Respiratory failure lymph node enlargement hypothermia diarrhea dry cough
60% of patients showed asymptomatic subclinical experience. Only in the coccidiostat skin test, 40% of patients had different clinical manifestations, mainly of the following types:
1. Infected with primary coccidioidomycosis 10 to 16 days after the onset of flu-like symptoms, dry cough, occasional blood stasis, often chest pain, chest signs often negative, 20% of patients with conjunctivitis, deformed erythema, nodular Allergic skin lesions such as erythema may be associated with multiple serositis (pleurisy, pericarditis, arthritis), the course of the disease is self-limiting, the symptoms may resolve within 6 to 8 weeks, and clinical fungalemia is prone to occur at the beginning of infection. However, there are very few devastating lesions outside the lungs, mainly found in the skin, joints, bones and meninges.
X-ray showed hilar lymphadenopathy, pleural reaction and pleural effusion, pulmonary nodular lesions can resolve within 6 to 8 weeks, few residual lung abnormalities, common pulmonary spores nodules and cavities .
2. Chronic progressive coccidiosis pneumonia After 8 weeks of primary infection, the lung lesions persisted, and the lesions gradually deteriorated, showing persistent low fever, cough, anorexia, weight loss, some patients have hemoptysis, and the course is slow and long. It can be several months to several years.
X-ray showed infiltrating shadow of lung segment or lung lobe, multiple cavities and fibrous nodule lesions, most of which were 2 to 4 cm, and a few were large cavities (>6 cm), typically thin-walled, with no obvious inflammatory infiltration around them. The two upper lungs are more common, and the coccidioid nodules usually have no calcification, and the doubling time is more than one year.
3. Mili-like pneumococcal disease This type is a serious complication of primary coccidioidomycosis. The pathogen is spread to the whole lung field and other organs outside the lung by blood, often in the course of primary pulmonary sporozoite. Early onset, can also be chronic progressive late complications, such as those with immunosuppressive and severe underlying diseases and susceptible races, clinical and X-ray findings resemble miliary tuberculosis, immune-impaired hosts, can rapidly develop into Respiratory failure, blood source spread can affect the skin, joints, lymph nodes, meninges, liver and spleen and other organs.
Examine
Examination of pulmonary coccidiosis
1. Peripheral blood: peripheral blood leukocytes can be increased, primary coccidioides often have elevated blood eosinophils, the most obvious onset of the second to third week.
2. Coccidioidoposis skin test: 90% to 95% of the patients were positive for the skin test after 4 weeks of primary infection, and the intradermal test was performed with coccidiostat. The dose was 0.1 ml, and the skin redness range was 5 mm. It can last for 24 to 48 hours, but the former infected person is also sustainable and positive, and the blood source disseminated patient can be negative.
3. Etiology examination: sputum, puncture fluid, fiber bronchoscopy specimens, membrane biopsy specimens, treated with potassium hydroxide, smear visible round thick wall, spheroids containing endospores, cultured on glucose peptone agar for 1 week Filament colony growth, positive culture of Pneumocystis has a special significance for the diagnosis, the positive rate of sputum culture is 40% to 60%, and the positive rate of bronchoscopy specimens is higher.
4. Serological examination: Serological method for detection of coccidioides antibody is rarely false positive, latex agglutination test sensitivity is up to 90%, often used for primary screening, complement binding test for detection of IgG antibodies, 50% of patients positive at the 4th week of infection, In the 8th week, 90% of the patients were positive, 6 to 8 months disappeared, the antibody titer was related to the severity of the disease, and the IgM antibody was detected by the test tube precipitation test. 50% of the patients were positive in the first week of infection, which is suitable for early diagnosis.
5. Gene probe diagnosis: Specific gene probe has been applied to the rapid diagnosis of pneumococcal disease, and the results can be obtained in 48 hours.
X-ray manifestations of primary pulmonary coccidioidomycosis are hilar lymphadenopathy, pleural reaction and pleural effusion. The onset of pulmonary nodular lesions can resolve within 6-8 weeks, and few residual lung abnormalities are common. Pneumococcal nodules and cavities.
Chronic progressive coccidioides pneumonia X-ray showed infiltration of lung or lung lobe, multiple cavities and fibrous nodule lesions, most of the cavities were 2 to 4 cm, and a few were large cavities (>6 cm), typically thin-walled. There was no obvious inflammatory infiltration around it, and it was more common in both lungs.
The clinical and X-ray findings of miliary coccidioidomycosis resemble miliary tuberculosis.
Diagnosis
Diagnosis and identification of pulmonary coccidioidomycosis
In the endemic areas, people with respiratory infections should be suspected of this disease, routine gonorrhizin test, according to the history of exposure to the epidemic area, clinical manifestations and X-ray features, immunological examination can be diagnosed, smear or culture found to be specific to Pneumocystis The sphere can be diagnosed.
The disease should be differentiated from bronchitis, pneumonia, tuberculosis, lung tumors, etc.
