Fungal pneumonia is a mycotic lesion of the lungs, the causative agents of which are various types of fungi. The disease is manifested by fever, weakness, cough with mucopurulent sputum and hemoptysis, shortness of breath, chest pain, myalgia. The diagnosis of fungal pneumonia is made according to anamnesis, symptoms, lung radiography, microbiological, serological and molecular genetic studies. Treatment of fungal pneumonia includes the appointment of antimycotic drugs, immunocorrectors, multivitamins, detoxifying and desensitizing agents.
Fungal pneumonia (pneumomycosis) is an inflammatory process that develops in the alveoli and parenchyma of the lungs during the introduction and uncontrolled reproduction of pathogenic or conditionally pathogenic strains of fungi. Fungal pneumonia can occur as an independent (primary) disease with direct infection of lung tissue or secondarily as a complication of another background, including respiratory pathology (bronchiectatic disease, obstructive bronchitis, lung abscess).
Fungal pneumonia is considered one of the most severe forms of pneumonia, the number of cases of which has been increasing recently, despite the use of the latest antimycotic drugs in pulmonology. The specificity of pathogens and the torpid course of pneumomycosis present great difficulties for accurate diagnosis and delay the timely initiation of therapy, exacerbating inflammatory changes.
Fungal pneumonia causes
The cause of the development of fungal pneumonia is the colonization of the mucous membrane of the lower respiratory tract by strains of fungi, many of which are representatives of conditionally pathogenic microflora. The causative agents of the disease can be fungi of various species – mold (Aspergillus, Mucor), yeast-like (Candida), endemic dimorphic (Blastomyces, Coccidioides, Histoplasma), pneumocysts (Pneumocystis). Candida fungi (C. albicans), Aspergillus and pneumocysts (P. carinii), which have a predominant tropism to lung tissue, are most often detected in fungal pneumonia.
Depending on the causative agent, pneumomycosis is divided into:
- lung aspergillosis lung
- candidiasis lung
- mucomycosis pneumocystosis
Pathogenic fungi – pathogens of exogenous pneumomycosis (Aspergillus, Mucor, Blastomyces, Coccidioides, Histoplasma) can be present in soil, water, industrial and household dust, in damp rooms, on rotten wood, insufficiently treated medical equipment and penetrate into human lungs mainly by inhaling air contaminated with mycelium and spores (airborne droplets-dusty way). The causative agent of pneumocystis pneumonia is transmitted only from person to person. First, a temporary, and then a persistent carrier is formed with the development of fungal pneumonia.
Fungal pneumonia can manifest as a mixed infection (mixed, caused by various types of fungi – yeast-like and mold-like) and combined, caused by fungi and other microorganisms (for example, Aspergillus with gram-negative microflora). Thoracic actinomycosis is a pseudomycosis, as it is caused by anaerobic bacteria of the genus Actinomyces and is accompanied by the formation of an infectious granuloma (actinomycoma) with germination into surrounding tissues and the appearance of purulent fistulas.
Pathogens of endogenous fungal pneumonia enter the lungs from other foci of mycosis present in the body: by aspiration (for example, with candidiasis of the oral cavity, trachea, bronchi) or by hematogenic and lymphogenic pathways – with a widespread lesion. Candida fungi present in the microbiocenosis of the skin and mucous membranes of the respiratory tract, under certain conditions, become active, acquire pathogenicity and cause pneumomycosis.
Fungal pneumonia often develops in patients with malignant blood diseases (acute leukemia) and lymphoproliferative tumors receiving long-term radiation or systemic chemotherapy (immunosuppressants and glucocorticoids); as a complication of HIV infection and AIDS, diabetes mellitus, aplastic anemia, tuberculosis, conditions after organ transplantation, artificial lung ventilation. The occurrence of fungal pneumonia is facilitated by a violation of the normal microflora (dysbiosis of the respiratory tract) associated with prolonged and irrational use of antibiotics. Agranulocytosis is among the main factors of development and reactivation of fungal pneumonia in 50% of patients. Fungal pneumonia is often combined with mycotic lesions of the mucous membranes, skin, nails.
The realization of the pathogenic potential of fungi is always facilitated by the suppression of factors of specific and nonspecific general and local resistance of the organism with the development of an immunodeficiency state. Colonizing the lumen of the bronchioles and alveoli, fungi begin to multiply actively, causing the migration of leukocytes and the accumulation of serous fluid. During the period of exacerbation, mycotic damage to lung tissue is characterized by the presence of decay zones in the form of cavities, sometimes by the formation of abscesses in which fungal accumulations are found; during the recovery period, areas of dense granulation tissue appear in their place.
Fungal pneumonia symptoms
In most cases, the onset of pneumomycosis is characterized by an unclear clinical picture, with minor, sometimes atypical symptoms and manifested by episodes of fever, weakness, dry cough, myalgia. Intoxication is associated with the action of mycotoxins. The appearance of purulent sputum at the rupture of abscesses formed by the accumulation of fungi in the lung tissue makes the picture of the disease more pronounced.
Massive single infection with exogenous fungi provokes an acute process, in the case of repeated small doses of pathogens and in weakened patients, pneumomycosis takes a chronic course with relapses. Excessive development of connective tissue leads to shortness of breath, streaks of blood in the sputum (sometimes profuse pulmonary bleeding). Mixed forms of pneumomycosis are more severe than monoinfection. Fungal pneumonia can be complicated by exudative or fibrinous pleurisy when an abscess is opened into the pleural cavity or the fungus germinates into the pleura; the development of respiratory (including acute) and cardiovascular insufficiency. The course of pneumomycosis of various etiologies has certain clinical features.
Aspergillosis of the lungs
Aspergillosis pneumonia can be acute and chronic, and include severe lightning-like forms. They are often characterized by signs of abscessing pneumonia, possible involvement of the pleura and lymph nodes, as well as the formation of specific suppurating granulomas. Almost constant coughing attacks with copious mucopurulent or purulent secretions (in the form of dense lumps) and an admixture of blood, pain and heaviness in the chest, shortness of breath, turning into suffocation, prolonged subfebrility with temperature jumps, chills and night sweating are disturbing. There is a severe general condition, severe weakness, anorexia and cachexia.
It is possible for fungi to germinate the walls of blood vessels with the formation of thrombosis and hemorrhagic infarcts. Chronic aspergillosis pneumonia is secondarily layered on various lung lesions, manifesting symptoms of the underlying disease and fungal lesions. The localized form – aspergilloma of the lungs occurs when fungi infect an existing cavity in the lung tissue and often proceeds asymptomatically. With fungal pneumonia, abscessing can become a chronic process.
Candidiasis of the lungs
Primary candidiasis pneumonia can be accompanied by signs of intoxication at normal body temperature, sometimes it can begin acutely with fever, shortness of breath, cough with scant sputum, hoarseness of voice, chest pain, increased sweating. A typical bilateral lesion, in young children, a recurrent course with a transition to chronic granulomatous generalized candidiasis is possible. Secondary candidiasis pneumonia proceeds heavily with a suffocating cough, purulent-bloody sputum, vomiting, dehydration. It often acquires the character of a progressive destructive process with the formation of large thin-walled cysts in the lungs, the development of lung atelectasis, miliary dissemination or septic condition.
Pneumocystis pneumonia occurs as a mono- or mixed infection, often asymptomatic or with an erased clinic, may occur latently already in the first years of life. The probability of subsequent reinfection is not uncommon. It is characterized by a gradual increase in hypoxemia and respiratory disorders, prolonged unproductive cough against the background of scant physical and radiographic data. Premature infants have a manifest form of pneumocystis pneumonia with prolonged, pronounced respiratory failure. Arising as the first of the opportunistic infections in immunocompromised patients, pneumocystosis has a rather long sluggish course, complicated by spontaneous pneumothorax, the addition of superinfection. In the absence of specific treatment, a fatal outcome is possible.
Determining the genesis of fungal pneumonia is often difficult due to the peculiarity of mycotic infection, therefore a comprehensive approach is needed with an analysis of anamnesis, clinical symptoms, results of lung x-ray, microscopic, cultural, serological (ELISA, RSC, RPGA, RNIF) and molecular genetic (PCR) examination of sputum, blood, lavage and pleural fluid, aspirate lung tissue.
With aspergillosis, a picture of abscessing pneumonia and the phenomenon of purulent bronchitis is revealed. If there is data for previous antibiotic treatment and there is no response to therapy, fungal pneumonia may initially be suspected. The presence of a focus of mycosis in the form of thrush of the oral cavity gives reason to think about the candidiasis nature of the disease. It should be borne in mind that in the presence of an immunodeficiency condition, the risk of developing fungal pneumonia is much higher.
With fungal pneumonia, a therapist or pulmonologist ausculates multiple dry, then wet, different-sized wheezes in the lungs. In the patient’s blood, eosinophilic leukocytosis with a shift to the left and an increase in ESR is detected. The X-ray shows an increase in the pulmonary pattern, infiltrative shadows of insignificant or huge sizes with uneven edges; when abscesses appear, randomly located cavities with a fluid level are visible.
With pneumomycosis, fungal spores and mycelium can be detected by microscopy of a smear of sputum and bronchoalveolar fluid. Sputum vacuuming is important to carry out before the start of treatment, which increases the likelihood of isolation and identification of the causative agent of fungal pneumonia and its quantitative assessment. Direct detection of DNA and establishment of a strain of fungi in sputum by PCR should correlate with the presence of clinical manifestations of the disease. One fact of colonization of the respiratory tract by fungi in the absence of symptoms of an infectious lesion is insufficient for the diagnosis of fungal pneumonia. PCR examination of blood for fungi makes it possible to differentiate the disseminated and local forms of mycosis.
The material from the distal parts of the bronchi is obtained by bronchoscopy with bronchoalveolar lavage. In the flush, the causative agent of pneumocystis pneumonia is detected in 89-98% of cases. If necessary, it is indicated to obtain an aspirate (biopsy) by puncture or open lung biopsy. PCR for fungal pneumonia is informative even after the start of antibiotic therapy and allows simultaneous determination of the DNA of different pathogens in mixed infection. In serodiagnostics, an analysis of the dynamics of detection of antibodies to potential pathogens of fungal pneumonia is indicative.
Fungal pneumonia treatment
Since the use of antibiotics in fungal pneumonia will aggravate the course of the disease, the appointment of either specific antimycotic drugs (itraconazole, amphotericin B, fluconazole, ketoconazole, etc.), or folic acid inhibitors and clindamycin in pneumocystosis is required.
In case of fungal pneumonia, immunocorrecting drugs, multivitamins, detoxifying and stimulating agents, a rational regime and nutrition are used to eliminate the deficiency of immunity. In the case of the fungal-bacterial nature of pneumonia, a short course of antibiotics is indicated, and in combination with allergic symptoms, desensitizing drugs, corticosteroids are used. When pneumomycosis is complicated by exudative pleurisy, pleural puncture and washing of the pleural cavity are performed.
Prognosis and prevention
Accurate operative diagnosis and therapy make the prognosis of fungal pneumonia encouraging. In case of untimely and inadequate treatment, the risk of severe complications is high. Fungal pneumonia is one of the most common causes of death in AIDS patients. With a favorable prognosis of primary aspergillosis and candidiasis, a tendency to inflammatory diseases of the respiratory tract and fungal sensitization may persist; and pulmonary complications (pneumosclerosis) can lead to disability of the patient. In secondary fungal pneumonia, the prognosis depends on the severity of the underlying background disease.
Prevention of fungal pneumonia includes prevention in production and agriculture (sealing of technological processes associated with the release of dust; the use of respirators, microbiological control of the environment); in medicine and the food industry (compliance with the rules of disinfection and sterilization). Individual prevention implies strengthening the immune system, eliminating dysbiosis and chronic pathology, conducting rational antibiotic therapy.
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