Pulmonary candidiasis

Introduction to pulmonary candidiasis Lung candidiasis is a common pulmonary fungal disease caused by infection with Candida (mainly Candida albicans). The disease is mostly secondary infection, which occurs in the case of decreased body resistance. Clinically, it can be divided into three types: (1) bronchitis type. (2) Pneumonia type. (3) Allergic type. The pathogen is mainly Candida albicans, followed by Candida tropicalis, Candida highis and Candida albicans. Candida infections have been reported to account for 79% of fungal infections, especially in intensive care units, burns and oncology. basic knowledge The proportion of illness: 0.005% Susceptible people: no special people Mode of infection: respiratory transmission Complications: Myocarditis, bacteremia

Causes of pulmonary candidiasis

Decreased immune function (20%):

Normal human skin, oral cavity, gastrointestinal tract, etc. have parasitic parasitic, normal disease does not cause disease, when the body's immune defense function declines, colonization in the oral cavity, Candida in the upper respiratory tract can invade the respiratory tract and cause endogenous infection.

Cross infection (10%):

Intra-hospital cross-infection can cause exogenous infections, indwelling catheters, mucosal ulcers and other damage to the mucosal integrity, can also cause Candida to invade the body, the lungs can be a primary infection, but also a part of the blood-borne disseminated Candida.

Unclean diet (10%):

Unclean lungs can also cause lung candidiasis.

Pathogenesis

The main route of infection of bronchopulmonary candidiasis is inhalation (primary), that is, Candida colonized in the oral cavity and upper respiratory tract, which is caused by the lower respiratory tract and alveoli when the body's defense mechanism is weakened. Candida is invaded into hyphae after invading the tissue. Type, mass reproduction, Candida albicans has anti-phagocytic ability, causing acute inflammatory reaction of leukocyte infiltration, ulceration, multiple microabscess and tissue necrosis, chronic infection with granulomatous lesions and fibrous tissue hyperplasia, blood The source-dispersion type is a hemorrhagic nodule composed of hyphae and yeast invading into the blood vessel, causing diffuse damage to both lungs, typically characterized by necrotic lung tissue and mass-producing Candida.

Lung candidiasis prevention

1. Do not abuse broad-spectrum antibiotics.

2. Long-term application of antibiotics, glucocorticoids and immunosuppressive drugs should be regularly checked for feces, urine, sputum, etc., and carefully performed physical examination, if necessary, regular chest X-ray examination.

3. For those who must apply antibiotics and glucocorticoids for a long time, antifungal drugs such as nystatin, ketoconazole and fluconazole can be administered intermittently.

4. The medical staff should wash their hands before and after touching the patient to avoid cross infection.

Lung candidiasis complications Complications Myocarditis bacteremia

Occasionally, exudative pleurisy, main bronchial obstructive atelectasis, etc., blood-borne pneumonia can be complicated by myocarditis and bacteremia.

Symptoms of pulmonary candidiasis common symptoms mucous purulent lung sound

1. Tracheitis type: The patient is generally in good condition, no fever, coughing, white mucus or milky white, occasional bloodshot, chest X-ray showing thickening of the lungs.

2. Bronchial pneumonia type: The onset is more urgent, there may be chills, fever, cough and more drama, sputum is white sticky jelly, sometimes with bloodshot or purulent sputum.

3. Pneumonia type: In addition to the above symptoms, blood-borne pneumonia may be associated with skin damage, myocarditis, candida bacteremia, shock, chronic cases of diffuse fibrosis and emphysema.

Examination of pulmonary candidiasis

1. Pathogen examination:

(1) throat swab, sputum, bronchoalveolar lavage fluid, pleural effusion, blood and other direct smear microscopy or Gram stain, Iemsa staining or PAS staining, bud spores and pseudohyphae and bacteria found in the specimen Silk has diagnostic value.

(2) Because normal people can carry bacteria in the throat, sputum culture more than 3 times positive has a certain diagnostic significance.

(3) Spiral bronchoscopy protective brush (PSB) sampling culture is more reliable, because the bacteremia duration is short, so the blood culture positive rate is low.

2. Histopathological examination: Fiberoptic bronch biopsy or percutaneous lung biopsy, histopathological examination with evidence of Candida hyphal invasion can confirm the diagnosis.

3. Immunological examination: sensitivity and specificity are not ideal. In severe cases, immunodeficiency is often false negative. The detection of Candida antigen mainly includes mannan antigen, 47KD antigen, heat labile antigen, but Candida. There are common antigens between different species, and some protein components in human serum have similar antigenic determinants to Candida antigens. Therefore, there are problems in purification and standards of antigens, and the sensitivity and specificity need to be further improved.

4. Imaging examination: chest X-ray of bronchial pneumonia showed deepening of the texture of the two lungs, diffuse speckles in the lower lungs of both lungs, small patches of shadow, pneumonia X-ray showed flaky, nodular infiltration, The whole lung lobe can be affected, and there may be swelling of the hilar or mediastinal lymph nodes, or pulmonary edema. The shadow changes greatly in the short term, and the blood-derived multiple manifestations are multiple miliary nodules with unclear margins. As the disease progresses, Miliary lesions can be fused into small nodules of varying sizes.

Diagnosis and identification of pulmonary candidiasis

The lower respiratory tract secretion, the lung tissue, the pleural effusion, the blood, the urine or the cerebrospinal fluid can be directly smeared or cultured with Candida by a ring-shaped membrane puncture or by a fiberoptic bronchoscope. The sputum can be directly coated. Tablets or cultured Candida can not be diagnosed as fungal disease, because about 10% to 20% of normal people can find Candida albicans, if 3% hydrogen peroxide contains 3 times, coughing from deep cough 3 consecutive Candida, which cultivates the same strain, has diagnostic reference value.

Differential diagnosis

1. Bacterial pneumonia: Bacterial pneumonia often has high fever, cough, cough, chest pain, shortness of breath, etc., lung signs and wet sputum, white blood cells rise, chest radiograph shows flocculent infiltration shadow, but pathogen It is difficult to diagnose and isolate pathogenic bacteria from sputum or pleural fluid.

2. Viral pneumonia: Viral pneumonia usually causes upper respiratory tract infection, and then spreads down to cause inflammation of the lungs. Due to impaired respiratory mucosal defense function, bacterial infection is often induced. According to throat swab, sputum virus isolation and serum Specific antibody assay.

3. Tuberculosis: common in young patients, with low fever, night sweats and other symptoms, early irritating dry cough, and later sputum, coughing increased after the formation of cavities, increased sputum, half of patients may have hemoptysis, diagnosis mainly based on chest X-ray examination and sputum Tuberculosis or tuberculosis-specific pathological changes were found in other specimens.

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