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symptoms of non-tuberculous mycobacteriosis, early symptoms and signs of non-tuberculous mycobacteriosis

symptoms of non-tuberculous mycobacteriosis, early symptoms and signs of non-tuberculous mycobacteriosis

Symptoms of non-tuberculous mycobacteriosis

Typical Symptom: Invasion of Lung

Non-tuberculous mycobacteria can cause pulmonary and extrapulmonary lesions with different clinical manifestations. The clinical manifestations of non-tuberculous mycobacterium lung disease are similar to tuberculosis, and most patients have slow onset, such as cough, expectoration, sputum blood, low fever, emaciation and fatigue. There can also be no obvious symptoms or only a slight cough and expectoration, and the lesions are found by lung X-ray examination. There are also high fever, chills, cough and chest pain, which are similar to acute lung infection. Some people are complicated with other lung diseases, Such as chronic obstructive pulmonary disease, Bronchiectasis, cystic fibrosis, pulmonary tuberculosis, pneumoconiosis, or systemic diseases, such as diabetes, or long-term use of glucocorticoid drugs, resulting in confusing clinical manifestations and difficult to distinguish, and the clinical manifestations of HIV infection and AIDS patients complicated with non-tuberculous mycobacterial lung disease or disseminated non-tuberculous mycobacterial disease are even more atypical.

Non-tuberculous mycobacterium extrapulmonary lesions include lymphadenitis, skin and soft tissue infection, bone and joint lesions, reproductive system, digestive system and nervous system lesions, and systemic disseminated lesions.

The diagnosis of non-tuberculous mycobacterium lung disease should be combined with contact history, susceptibility, basic diseases, clinical manifestations, chest X-ray manifestations, pathogenic bacteria examination and even histopathological examination.

1. Chest X-ray examination Chest X-ray plain film often shows fibrous nodular shadows in single and bilateral upper lung fields. When the disease progresses, the lesions are enlarged and fused, and the boundaries are blurred, and thin-walled cavities appear. There are few infiltrating and spreading lesions around the cavities, and chronic cavities are thick-walled and honeycomb shadows. Lower lobe tip lesions in both lungs are also common. Diabetes mellitus and other immunosuppressive patients often show small nodular lesions in the middle and lower fields, and pleural effusion is rare. High-resolution chest CT scan can more clearly show lung lesions and accompanying multiple bronchiectasis.

2. Bacteriological examination sputum and bronchoalveolar lavage fluid smear and culture are the most common examination methods. The smear is positive by acid fast staining (Ziehl-Neelsen), but the detection rate is low, and it cannot be distinguished from Mycobacterium tuberculosis. Culture and biochemical tests such as nicotinic acid test, catalase test and aromatic sulfate esterase activity are required.

But the inspection cost time, Can't get the test results early, In recent years, some rapid culture and bacterial type identification methods have been applied clinically, Such as BACTEC liquid radionuclide medium combined with nucleic acid probe, It can significantly save the detection time and provide rapid and accurate diagnosis for common Mycobacterium avium and Mycobacterium kansas. However, due to the heterogeneity of genes, the sensitivity to some Mycobacterium tuberculosis detection is not high, and the incidence of drug resistance of non-Tuberculosis Mycobacterium to commonly used anti-tuberculosis drugs is high, so drug resistance detection should be carried out.

Because the clinical manifestations of non-tuberculous mycobacterium lung disease are often confused with tuberculosis, which affects the diagnosis and treatment, when patients with "tuberculosis" have the following conditions, they should be examined for non-tuberculous mycobacterium while being treated with anti-tuberculosis drugs.

(1) Sputum culture was positive, but the colony morphology and occurrence were inconsistent with that of Mycobacterium tuberculosis.

(2) For the first time, mycobacteria isolated from newly treated patients were resistant to first-line and second-line anti-tuberculosis drugs.

(3) The patient was ineffective after being treated with various anti-tuberculosis drugs, and the sputum bacteria continued to be positive.

(4) Newly discovered pulmonary tuberculosis patients, with extensive cavities and mild symptoms, still excreting bacteria after 3 ~ 6 months of regular chemotherapy, or infiltrating lesions without cavities, still excreting bacteria after more than 6 months of regular chemotherapy.

(5) Patients with lung diseases accompanied by immunodeficiency, such as diabetes, silicosis, long-term use of immunosuppressants and HIV/AIDS patients.

(6) Acid-fast bacilli were found in sputum, and the clinical manifestations were inconsistent with pulmonary tuberculosis.

3. Trial Scheme for Diagnosis of Atypical (Non-tuberculous) Mycobacterium Lung Disease (Tuberculosis Science Society of Chinese Medical Association, 1988)

(1) Chest X-ray: There are abnormal shadows, and the lesions are often parallel to the discharge of bacteria, and tuberculosis infected persons have been excluded.

(2) Bacterial examination:

① The newly discovered cases had the same pathogenic mycobacteria in two of the three cultures within one month.

Patients with chronic lung disease were cultured once a month within 6 months, and more than 3 times proved to be the same pathogenic mycobacteria.

③ Non-tuberculous mycobacteria found in sterilized puncture materials, biopsies, surgical specimens and biopsy lung lesions, but there are no other pathogenic bacteria (note: intracellular mycobacterium infection is diagnosed, and sputum culture colonies are more than 100 at least once).

4. Diagnostic Criteria for Nontuberculous Mycobacteriosis (American Society of Thoracic Diseases, 1997)

(1) Clinical criteria:

① Clinical symptoms and signs: Cough and fatigue are common, fever, weight loss, hemoptysis and shortness of breath are common in patients with severe illness, and clinical symptoms deteriorate in patients with basic diseases.

② Exclude other diseases: such as tuberculosis, tumor and histoplasmosis.

(2) X-ray standard:

① Invasive lesions with or without nodular lesions (lasting ≥ 2 months, or progressing); Cavity lesion; Single or multiple nodules.

② HRCT showed multiple small nodules or multifocal bronchiectasis with or without small pulmonary nodules.

(3) Bacteriological criteria:

① There were at least 3 sputum or bronchial lavage specimens in one year, of which 3 were positive in culture but negative in AFB smear, or 2 were positive in culture and 1 was positive in AFB smear.

② If only one bronchial lavage specimen is obtained, but no sputum specimen is obtained and the culture is positive,At the same time, the smear was positive.

③ If sputum or bronchial lavage fluid specimens indicate that other diseases cannot be diagnosed or excluded, positive results can be obtained by bacterial culture and histopathological examination through bronchial biopsy or lung biopsy.

The risk factors of HIV seropositive patients include local immunosuppression, such as alcoholism, bronchiectasis, cyanotic heart disease, cystic fibrosis, pulmonary fibrosis, smoking and chronic obstructive pulmonary disease. Severe systemic immunosuppression, such as leukemia, lymphoma, organ transplantation and other immunosuppressive therapy, HIV serum test positive, CD4【小于】200.


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