Fungal infection of the lungs

Introduction to pulmonary fungal infections Pulmonary fungal infections are bronchial-pulmonary diseases caused by fungal infections, including primary and secondary pulmonary fungal infections. Fungal spores and the like are inhaled into the lungs of the human body and cause disease called primary pulmonary fungal infection. Fungal infections in other parts of the body cause disease through lymph or blood to the lungs, called secondary pulmonary fungal infections. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: non-infectious complication:

Cause of pulmonary fungal infection

Pulmonary fungal infections are allergic, suppurative, or chronic granulomas caused by different pathogens. Pathogenic fungi causing lower respiratory tract fungal infections Pathogenic fungi and conditional pathogenic fungi: 1 Pathogenic fungi are primary pathogenic bacteria, often leading to primary fungal infections, invasive immune function normal hosts, immune function defects The patient is prone to spread throughout the body. Pathogenic fungi mainly include histoplasma, coccidioides, paraspora, dermatitis, ampulla and sporotrichosis. 2 Conditional pathogenic fungi or opportunistic fungi, such as Candida, Aspergillus, Cryptococcus, Mucor and Penicillium, Rhizopus, Absidia, Fusarium and Pneumocystis. These fungi are mostly saprophytic bacteria, which are weak to the human body, but when the host has a predisposing factor, it will lead to deep fungal infection, but clinically, there are cases without clear host factors. Common clinical fungal pathogens include Candida, Aspergillus, Mucor, Cryptococcus, Histoplasma and so on. In recent years, with the aging of the population, organ transplantation, tumor radiotherapy and chemotherapy, hematopoietic stem cell transplantation, application of extended-spectrum antibiotics, corticosteroid use, and various catheter interventions, the incidence of pulmonary fungal infection has increased year by year.

Prevention of pulmonary fungal infection

Most of the clinically seen fungal pneumonia is secondary to the long-term application of broad-spectrum antibiotics, glucocorticoids, and immunosuppressive agents. It can also be induced by indwelling catheters in the body. Therefore, comprehensive prevention measures such as the rational application of antibiotics, glucocorticoids, and prevention of nosocomial infections are particularly important.

Pulmonary fungal infection complications Complication

Pulmonary fungal infection symptoms Common symptoms Chest tightness Cough fever with chills

Pulmonary fungal infections are often secondary to severe primary disease. Symptoms and signs are often non-specific and may have the following clinical manifestations:

Occult infection

No obvious symptoms and signs, can be self-healing.

2. Influenza-like symptoms

It is characterized by fever, chills, headache, runny nose, joint pain, and myalgia.

3. Pulmonary performance

(1) Pneumonia or bronchitis is the most common, and it is difficult to identify with common bacterial pneumonia. May have fever, cough, white sticky or purulent sputum, hemoptysis, chest tightness, asthma and other respiratory symptoms, lungs can be heard and dry and wet voice, may be associated with low to moderate pleural effusion. (2) Tuberculosis-like manifestations The clinical manifestations of histoplasmosis and dermatitis germination are sometimes similar to tuberculosis. There may be respiratory symptoms such as dry cough, hemoptysis, chest pain, and symptoms of tuberculosis such as low fever and night sweats in the afternoon.

(3) lung abscess and empyema often acute onset, may have chills, high fever (more relaxation heat), cough, mucus purulent sputum, sometimes sputum odor, hemoptysis is mostly blood in the sputum.

(4) Tumor-like manifestations such as cryptococcal tumor, histoplasmosis, coccidioidoma, etc., resemble peripheral lung cancer. Dermatitis bud disease, Aspergillus infection, etc. can destroy the ribs and vertebrae, which is like bone metastasis of metastatic cancer.

(5) pulmonary embolism and pulmonary infarction such as vasculature mucor, easy to invade blood vessels, lung infection often lead to pulmonary embolism and even pulmonary infarction, like pulmonary thromboembolism.

(6) Others can cause diffuse pulmonary interstitial lesions, or similar sarcoidosis.

Examination of pulmonary fungal infections

Pathological changes may have an allergic, suppurative inflammatory response or formation of chronic granulomas. X-ray findings are non-characteristic and can be bronchial pneumonia, lobar pneumonia, diffuse nodules, and even shadows of the mass. Diagnosis depends on the identification of fungal forms of culture results.

Diagnosis and identification of pulmonary fungal infection

The clinical manifestations of pulmonary fungal infection are non-specific, and the diagnosis is classified according to the diagnostic criteria of invasive pulmonary fungal disease classification (level 3), which is divided into diagnosis, clinical diagnosis and diagnosis. The diagnosis requires only microbiological evidence (smear and culture) determined by histology or sterile body fluid testing, and does not involve host factors. Clinical diagnosis requires a combination of host factors, clinical features, and microbiological evidence. The diagnosis is in accordance with host factors, clinical features, and lack of microbiological evidence. Immunological detection of serum cell wall components (1,3)--D-glucan antigen detection (G test), galactomannan antigen detection (GM test) positive has important diagnostic value. The following is a summary of several common pulmonary fungal infections:

Lung candidiasis

Found in high-risk groups such as granulocytopenia, central venous indwelling catheter, major abdominal surgery, hormone and antibiotic treatment, diabetes, renal insufficiency, and organ transplantation. Clinical symptoms have persistent fever and respiratory symptoms that cannot be explained, but the signs are mild. Cough, even cough, cough a small amount of white mucus or thick. Blood type disseminated type often has rapid progression of circulation and respiratory failure. X-ray showed bronchial pneumonia changes or flaky infiltration or fusion, and there may be void formation. Lower respiratory tract secretions, lung tissue, pleural effusion, direct smear of blood or cultured Candida can be diagnosed. Direct smear or culture of sputum can not be diagnosed as fungal disease, because 10% to 20% of normal people can find Candida albicans, if 3% hydrogen peroxide contains 3 times from deep coughing ( Qualified ) Candida cultured with the same strain for 2 consecutive times has diagnostic reference value. Positive blood cultured Candida is a reliable diagnostic evidence for Candida bacteremia. Some patients have a positive G test (except for false positives), which can provide an important reference for clinical diagnosis.

2. Pulmonary aspergillosis

Clinical manifestations are complex, three common types: allergic bronchopulmonary aspergillosis (more common allergic constitution), Aspergillus ball (the most common symptom is hemoptysis) and invasive pulmonary aspergillosis (for granulocyte deficiency or receiving broad-spectrum antibiotics, hormones, During the treatment of immunosuppressive agents, unexplained fever, dry cough, chest pain, hemoptysis, etc.). Diagnostic criteria for allergic bronchopulmonary aspergillosis include:

(1) repeated asthmatic attacks;

(2) Peripheral blood eosinophils increased by 1X109/L;

(3) X-ray transient or migratory lung infiltration;

(4) serum total IgE concentration 1000mg / ml;

(5) Aspergillus antigen test is positive;

(6) positive for serum precipitin antibody;

(7) Increased specific anti-Aspergillus IgE and IgG titers;

(8) Central cystic bronchiectasis.

Pulmonary aspergillosis can be diagnosed according to imaging features, but it needs to be differentiated from other fungal balls, hamartoma, lung cancer, hydatid cyst, and lung abscess. Diagnosis requires pathogens and histopathology. Pulmonary Aspergillosis CT features a rounded dense shadow in the lung cavity or pleural cavity with a light-transmissive vignetting at its edges. If the cavity is large, it can be seen that the spherical shadow has a pedicle connected to the wall of the hole, and the shape is like a pendulum. The spherical shadow can change shape with the change of body position. If the cavity is small, the spherical lesion fills most of the cavity, and its vignette is small, showing only a narrow half-moon translucent band. Invasive pulmonary aspergillosis CT features: early inflammation of the shadow, surrounded by misty exudation ("halo sign"), followed by inflammatory lesions in the air cavity consolidation, visible bronchial aeration sign, and then visible lesions appear half-moon shape The light zone ("air half moon sign") can be further transformed into a complete necrotic cavity. Its diagnosis uses the above-mentioned level 3 diagnostic criteria. Positive GM test provides an important reference.

3. Pulmonary cryptococcosis

The pathogenicity of Cryptococcus is mainly Cryptococcus neoformans and its variants (currently at least 9). Clinical symptoms and signs: from asymptomatic to acute pneumonia, the difference is very large, no specificity, combined with meningitis may have headache, dizziness, vomiting and other meningeal irritation.

Imaging findings: nodules or clumps are more common, accounting for 40% to 60%, single or multiple, seen in one or both lung fields, often under the pleura, varying in size, 1 to 10 cm in diameter, margin Finishing, can also be expressed as fuzzy or small burrs. There are often holes to form a relatively smooth wall, and in the early stage, there may be uniform, unconventional low-density areas in the appearance of nodular density. Low-density necrosis or cavities with nodules or agglomerations have important reference value for pulmonary cryptococcal lung disease, especially in multiple cases. Such signs are more common in patients with sound immune mechanisms; lung parenchymal infiltration accounts for 20%~ 40%, unilateral or bilateral, difficult to distinguish from other pathogens pneumonia, more common in patients with low immune function; diffuse miliary shadow or interstitial lung lesions are relatively rare, can occur in AIDS patients; pleural effusion is less common, Once present, the extraction of fluid for pathogen examination has important diagnostic implications.

Etiology and histopathological examination: The positive rate of 1 and lower respiratory tract sampling culture is not high, and the specificity is low, but it still has reference value in AIDS or other immunosuppressed patients. 2 antigen detection: polysaccharide antigen detection of cryptococcal capsules with high specificity. The positive rate of serum antigen detection in patients with pulmonary cryptococcosis is <40%, so the application of BALF and pleural effusion is recommended. 3 histopathological examination: any conditional patients should use percutaneous or transbronchial lung biopsy for histopathological examination. In the granulomatous or jelly-like lesions, a typical yeast type with a capsule, a narrow neck, a bud but a sterile silk is found to have a diagnostic significance. In the absence of host factors and imaging suggests that the disease is likely to be diagnosed by percutaneous or transbronchial lung biopsy as much as possible to avoid unnecessary surgery.

4. Pneumocystis pneumonia

The vast majority of this disease is seen in AIDS patients and other reasons for cellular immunosuppressive patients. Fever, dry cough, and progressive dyspnea, hypoxemia are the main clinical symptoms of this disease. Even if there is a large inflammatory change in the lungs, there are few signs. In the early stage of imaging, there were diffuse alveolar and interstitial infiltrative shadows, which rapidly merged into a wide range of lung consolidation, showing bronchial aeration. Generally do not involve the lung tip, lung base and extrapulmonary zone. If the patient continues to have fever for >96 hours, it is ineffective by active antibiotic treatment; it also has symptoms and signs of pulmonary infection: cough, cough, hemoptysis, chest pain and dyspnea, and lung vocal or pleural friction sound; imaging examination It can be seen that new non-specific lung infiltrates in addition to the main clinical features need to be considered for this diagnosis. Cough, sputum, bronchoalveolar lavage specimens or lung biopsy specimens are still the basic diagnostic method for this disease.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.