Staphylococcal pneumonia is an acute inflammation of the lung tissue caused by the pyogenic microbe Staphylococcus aureus, occurring with a high risk of destructive complications. The clinic of the disease is characterized by severe intoxication, febrility, recurrent chills, severe shortness of breath, cough, sometimes with purulent sputum. The diagnosis of staphylococcal pneumonia is based on the results of radiography and CT of the lungs, laboratory examination of pathological material and blood. With staphylococcal pneumonia, an intensive course of antibiotic therapy and detoxification therapy is carried out; according to the indications – bronchial sanitation, drainage of the pleural cavity.
J15.2 Pneumonia caused by staphylococcus
Staphylococcal pneumonia is a bacterial infection of the lungs that tends to abscess and develop pleural complications. It is one of the varieties of bacterial pneumonia, accounts for 5-10% of all hospital and 1-2% of outpatient pneumonia. The course of staphylococcal pneumonia is very severe, with a possible re-development of manifestations after recovery and a high percentage of mortality (up to 30-70%). Staphylococcal pneumonia is most common in young children and the elderly. The largest number of episodes is recorded in the period from October to May. The increase in the number of annually recorded cases of bacterial pneumonia is associated with the high prevalence of pathogenic strains of staphylococci, the rapid formation of their polyresistance to antibiotics.
Causes of staphylococcal pneumonia
The causative agents of staphylococcal pneumonia are representatives of the pyogenic microflora of the Staphylococcus family, mainly Staphylococcus aureus. St. aureus is represented by g + cocci of almost regular spherical shape with a diameter of 0.6-0.9 microns, which can be found singly, in pairs, in small chains (of 2-4 cocci), but more often irregular clusters in the form of bunches of grapes. St. aureus persists on the skin and mucous membranes of the upper respiratory tract in 15-30% of healthy adults (in the neonatal period – in 90% of children).
The ways of penetration of staphylococcus into the lungs are aspiration, hematogenic, less often – inhalation. Staphylococcal pneumonia in some cases develops independently (with airborne infection in community-acquired conditions), but more often acts as a complication of infectious processes (septicopyemia, staphylococcal endocarditis, purulent thrombophlebitis with hematogenic spread and the formation of a metastatic pulmonary focus).
Staphylococcal pneumonia always occurs in the presence of risk factors: infection in the nasopharynx, microaspiration of nasal and oral secretions, reduction of general and local immunity, severe debilitating diseases, surgical interventions, injecting drug addiction, chronic alcoholism, unfavorable epidemiological situation. The development of staphylococcal pneumonia is facilitated by prolonged hospitalization and stay in nursing homes, irrational antibiotic therapy, tracheal intubation, ventilators, transferred acute respiratory infections (influenza, measles), causing damage to the atrial epithelium of the respiratory tract and contributing to their colonization by staphylococcus.
The ability of staphylococci to secrete large amounts of toxins (hemolysin, cytoxin, leukocidin) and enzymes (lipases, nuclease, staphylokinase, coagulase) provokes the destruction of the lungs with intense hemorrhagic necrosis of extensive areas of the parenchyma. This process is accompanied by the formation of air bubbles up to 5-10 cm in size (bull, pneumocele), and with suppuration – the development of peribronchial abscess. In 50-95% of cases, extrapulmonary effusion appears. With the rupture of small subpleural abscesses, a pyopneumothorax occurs; in the presence of communication with the bronchus, a bronchopleural fistula is formed. Venous septic thrombi can form in the focus of significant inflammation and destruction of lung tissue.
Symptoms of staphylococcal pneumonia
The clinical picture is usually preceded by symptoms of acute respiratory infections, purulent infection of the skin or internal organs. Staphylococcal pneumonia proceeds according to the type of drain bronchopneumonia – unilateral or with a predominant lesion of one lung. The symptoms are quite diverse and depend on the virulence of the pathogen strain, the patient’s age and concomitant pathology. Staphylococcal pneumonia is characterized by a severe violent course with sudden deterioration, severe intoxication, high fever and recurrent chills, general malaise, severe shortness of breath, painful cough. Staphylococcal pneumonia occurs in various clinical forms: staphylococcal infiltration, bullous destruction of the lungs, abscessing pneumonia, metastatic destruction of the lungs, pulmonary pleural form.
- Staphylococcal infiltrate is accompanied by severe intoxication, asthmoid syndrome; resolves for more than 4-6 weeks, in the outcome, the formation of focal pneumosclerosis is possible.
- Bullous staphylococcal destruction of the lungs is observed most often. Staphylococcal bulls appear on the first day of the disease and with adequate treatment usually disappear after 6-12 weeks. Typical is a short period of fever, the absence of respiratory disorders, a favorable course. There is a risk of residual cysts remaining in place of destructive cavities.
- Abscessing pneumonia. The course of abscessing staphylococcal pneumonia before the breakthrough of the abscess is very severe – with febrility and chills, sharp weakness, chest pain in the abscess area, shortness of breath. The breakthrough of the abscess is accompanied by a productive cough, the release of copious purulent, sometimes bloody sputum, a decrease in temperature and a weakening of the intoxication syndrome.
- Metastatic staphylococcal destruction of the lungs in sepsis is characterized by bilateral lung damage, severe shock, increased respiratory failure, confusion. The picture of staphylococcal pneumonia against the background of infectious endocarditis is masked by signs of endocardial inflammation.
- The pulmonary-pleural form of staphylococcal pneumonia, which proceeds with the formation of infiltrative and abscessing pulmonary foci and pleural lesions, has a frequent outcome in parapneumonic and purulent pleurisy, empyema and pyopneumothorax. Intoxication, respiratory and cardiovascular insufficiency are increasing, tachypnea, cyanosis of the skin and lips, anxiety, followed by lethargy, gastrointestinal disorders (vomiting, loss of appetite, diarrhea, bloating) appear.
Staphylococcal pneumonia refers to severe forms of bacterial infection. Its course is associated with life-threatening complications, both infectious and toxic. The most dangerous complications are staphylococcal pericarditis, meningitis, osteomyelitis, multi-focal metastatic abscesses of soft tissues, toxic myocardial damage.
The diagnosis of staphylococcal pneumonia is based on the data of the clinical picture, radiography and CT of the lungs, microscopy of sputum smears, pleural effusion and blood, as well as serological tests.
In the initial stage of staphylococcal pneumonia, there is a shortening and dulling of the percussion sound; in the affected area – weakened bronchial breathing with scattered crepitating wheezes. During the formation of an abscess in its projection, small bubbly wheezing and amphoric breathing are detected; with staphylococcal infiltrate, breathing is weakened vesicular.
The excess of the leukocyte level >15-20×109 / l with a shift of the formula to the left, high ESR is recorded in the blood. In severe cases, an unfavorable prognostic sign is a decrease in the number of leukocytes < 5×109/l. Bacteriological examination allows to identify the pathogen in the foci of the disease (pulmonary and pleural cavities) and blood (bacteremia occurs in 20-50% of cases), to determine the degree of pathogenicity of strains and antibiotic sensitivity. Positive data of serological tests are noted – an increase in the titer of antitoxin and agglutinins to the staphylococcal autostamp.
If staphylococcal pneumonia is suspected, repeated lung radiographs are performed at short intervals. At an early stage, signs of nonspecific bronchopneumonia are detected. Staphylococcal infiltrates are visible as inhomogeneous polymorphic areas of darkening, usually at the borders of the pulmonary segments. After the formation of abscesses in the area of the infiltration focus, cavities with a horizontal liquid level are revealed. In the case of metastatic destruction of the lungs, cavities with liquid contents and perifocal infiltration are combined with air cavities that do not have walls.
Differential diagnosis is performed with other bacterial, viral, fungal pneumonia, infiltrative tuberculosis and suppurated lung cyst.
Staphylococcal pneumonia treatment
Patients are hospitalized in the department of pulmonology with the appointment of large doses of antibiotics (b-lactam penicillins, macrolides, lincosamines, fluoroquinolones, cephalosporins) first parenterally (intravenously, intramuscularly), then orally. Usually the course of treatment is 3-4 weeks, if necessary, it can be extended. Infusions of glucose-salt solutions, antistaphylococcal plasma are carried out. In the acute period, extracorporeal detoxification (including plasmapheresis, hemosorption) can be used, with severe anemia – hemotransfusion. Bronchodilators, diuretics, corticosteroids, and oxygen therapy are used to eliminate respiratory insufficiency. Correction of microcirculatory disorders and immune status is advisable.
With abscess formation, the development of pyopneumothorax and empyema, bronchoscopic sanitation, postural drainage, pleural puncture, drainage or thoracoscopic sanitation of the pleural cavity are performed. Therapeutic and rehabilitation procedures are effective – vibration massage, reflexotherapy, physical therapy, UHF, microwave and laser therapy.
The prognosis of staphylococcal pneumonia is quite serious. In the absence of aggravating pathology, the outcome is usually favorable, in some cases it is possible to preserve residual changes and chronization of the disease. The elderly and young children with severe septic course have a high mortality rate.
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