OVERVIEW
Pulmonary actinomycosis is a chronic pyogenic granulomatous disease caused by infection of the lungs by the anaerobic bacterium Actinobacillus israelensis. This bacterium is normally present in the oral cavity, dental caries, and tonsillar crypts. Most cases develop as a result of poor oral hygiene and inhalation of secretions containing Actinomyces particles. It can also come from hematogenous dissemination or direct spread of abdominal lesions.
Causes
Actinomycetes are often parasitized in human oral mucosa, gums, tonsils, colon and other places. When the body resistance is reduced, it can be inhaled due to oral secretions and invade the respiratory tract, first cause lesions in the bronchial tubes, and then invade the lung parenchyma, can also be due to esophageal lesions spread to the mediastinum, or abdominal infections across the diaphragm and pleura and lungs, in the lungs caused by suppurative pneumonia, and through the lobe interstitial space, pleura invade the chest wall, ribs, and the formation of sinus tracts. It may also invade the blood circulation and cause systemic dissemination.
Symptoms
Mostly slow onset. It starts with low or irregular fever, cough, and coughing up a small amount of mucus sputum. As the disease progresses and multiple abscesses form in the lungs, the symptoms worsen. High fever, severe cough, large amount of mucopurulent sputum with blood in the sputum or hemoptysis, accompanied by fatigue, night sweats, anemia and weight loss may occur. Extension of the lesion to the pleura can cause severe chest pain, invasion of the chest wall with subcutaneous abscess and fistula formation, often discharging pus mixed with clots. There is hyperpigmentation of the tissue around the fistula. Fistula can appear in the vicinity of the fistula after healing. If the mediastinum is involved, respiratory or swallowing difficulties may result, and in severe cases, death may result. There may be signs of lung abscess and pleural effusion.
Examination
1. Laboratory tests
(1) Blood tests Elevated blood white blood cell count and increased blood sedimentation.
(2) Pathogenetic examination Yellow particles with a diameter of 0.25-3mm can be seen in sputum, pus or sinus secretion. Observed under low magnification microscope is round, the central color is lighter, arranged in a radial shape, similar to spores. The particles were crushed for Gram staining, and Gram-positive Y-shaped branching bacterial filaments were seen under oil microscope. The specimen containing sulfur particles was placed on antibiotic-free medium under anaerobic conditions, and the growth of pathogenic bacteria was visible, combined with biochemical reactions and strain identification. The cultured strain is injected into the abdominal cavity of mice, and after 4-6 weeks, many small abscesses can be seen in the abdominal cavity, “sulfur particles” can be seen in the section, and gram-positive branching filaments can be seen in the microscopic examination.
2.Other auxiliary examination
X-ray shows bronchopneumonia, solid changes in the lungs, with multiple small translucent areas. It can also be manifested as mass shadow, and if it is spread by bloodstream, it can be manifested as cornified lesions in the lungs. In the advanced stage, there are pulmonary fibrosis and pleural thickening.
Diagnosis
Early stage is difficult to diagnose because there are no characteristic changes on clinical and X-ray. Confirmation of the diagnosis depends mainly on microbiologic and histologic examination. The diagnosis can be confirmed by finding sulfur particles in pus, sputum or tissue of the fistula wall, or anaerobic culture of pathogenic bacteria.
Differential diagnosis
This disease is more easily confused with tuberculosis, bronchial carcinoma and lung abscess; it is quite similar to Nucleococcal mycobacteriosis in terms of clinical and X-ray manifestations as well as the morphology of the causative organisms, and should be differentiated. Nucleococcus often invades the central nervous system, seldom forms chest wall fistula, no sulfur particles in the sputum, and is an aerobic bacterium.
Complications
Pulmonary actinomycosis lesions involving the pleura cause pleurisy or pyothorax, and can penetrate the chest wall to form a fistula, mediastinal involvement can lead to respiratory or swallowing difficulties, and severe cases can lead to death. Signs of lung abscess and pleural effusion may be present.
Actinomyces may occasionally invade the bloodstream causing actinomycosis sepsis and other organ diseases.
Treatment.
Penicillin G treatment is effective. A high dose is appropriate and can be reduced when the condition is stabilized. If the efficacy of penicillin is unsatisfactory, large doses of sulfonamides can be added, which can improve the efficacy. If allergic to penicillin or treatment is ineffective, streptomycin, erythromycin, lincomycin, tetracycline and cephalosporin antibiotics can be used instead. Chest wall abscess or pyothorax must be incised and drained. Long-standing actinomycosis pulmonary granulomas, fibrosis, bronchiectasis, chest wall or rib lesions, and fistulas can be surgically removed.
Treatment of pulmonary actinomycosis should be based on antibiotics. If there is abscess formation, surgical incision should be made to drain the pus, which can receive the effect of controlling inflammation.
1.Drug treatment
(1) Generally apply high-dose penicillin G treatment, intramuscular injection or add procaine local lesion closure. When available, antibiotics should be selected according to the drug sensitivity test. Such as with streptomycin, tetracycline and other joint use, may improve the efficacy.
(2) Sulfonamides can be used alone or in conjunction with antibiotics.
(3) Iodine preparation oral iodine preparation for the longer course of actinomycosis can obtain a certain effect.
(4) Immunotherapy is also effective. General application of actinomycetin for intradermal injection, actinomycetin immunotherapy can enhance the body’s immune ability.
2. Surgery
Pulmonary actinomycosis has formed abscess or broken left after the fistula, there are often necrotic granulation tissue proliferation, can be used surgical incision and drainage of pus or scraping granulation tissue. Because the lesion in the gland is not clear, and with the surrounding tissue adhesion, often the gland will be removed together.
3. Hyperbaric oxygen therapy
Because actinomycetes are anaerobic bacteria, in recent years, the application of hyperbaric oxygen therapy for pulmonary actinomycosis can play a better role in inhibiting the development of actinomycetes, and it is one of the comprehensive treatment methods currently used.