Streptococcal pneumonia is an infectious inflammation of lung tissue that develops with the participation of pathogenic bacteria of the genus Streptococcus. The disease affects children more often, mainly occurs as a complication of other respiratory infections. Streptococcal pneumonia occurs with fever, cough, shortness of breath, chest pain; it is often complicated by purulent pleurisy, pericarditis, abscess formation, glomerulonephritis. The diagnosis is verified by lung x-ray, determination of streptococcus in sputum, blood or pleural aspirate. When confirming the streptococcal etiology of pneumonia, it is preferable to prescribe penicillins; in the presence of effusion, thoracocentesis may be required.
Streptococcal pneumonia is bacterial pneumonia, the etiological agent of which is various types of streptococcus (beta-hemolytic, peptostreptococci, etc.). Pneumonia caused by bacteria of the genus Streptococcus pneumoniae (Pneumococcus) is usually considered in clinical pulmonology as an independent nosological form – pneumococcal pneumonia. The share of streptococcal pneumonia in the overall morbidity structure of adult patients is low – 1-4%. However, this pathogen often becomes the “culprit” of pneumonia in young children (20%), elderly and weakened persons, and also contributes to the development of purulent complications. Among focal pneumonias of various etiologies, the proportion of streptococcal pneumonia is about 10%.
Causes of streptococcal pneumonia
Representatives of the genus Streptococcus are pathogens of a wide range of streptococcal infections. Most often, these microorganisms cause pharyngitis, tonsillitis, sinusitis, scarlet fever, otitis, impetigo, but they can also cause meningitis, neonatal sepsis, infectious endocarditis, abscess of the brain and abdominal cavity.
Infections of the lower respiratory tract – tracheobronchitis and streptococcal pneumonia are rare. Beta-hemolytic streptococci of group A usually cause pneumonia in children, as well as patients suffering from diabetes mellitus and other severe concomitant diseases. There are cases of mass morbidity of soldiers undergoing military service (the largest epidemic of streptococcal pneumonia occurred in the First World War), but sporadic cases are usually found.
The method of penetration of streptococcus into the respiratory tract is airborne. The incidence of streptococcal pneumonia is higher in autumn and spring, during periods of SARS outbreaks. In most cases, bacterial infection of the lungs complicates diseases such as influenza, measles, whooping cough, chickenpox, sudden exanthema. Lung damage most often manifests itself in the form of segmental or interstitial pneumonia, less often – focal or lobar pneumonia.
Getting into the respiratory tract, streptococcus causes ulceration and necrosis of the mucous membrane of the trachea and bronchi, accompanied by abundant exudation and hemorrhages. In the lung tissue, pathological changes usually affect the interalveolar septa. Streptococcal infection spreads rapidly through the lymphatic system to the lymph nodes of the lung root and mediastinum. Hematogenically, the purulent flora penetrates into the pleural cavity: effusion with streptococcal pneumonia is usually abundant, by nature serous (serous-hemorrhagic) or liquid purulent.
Symptoms of streptococcal pneumonia
The clinical picture of streptococcal pneumonia differs little from pneumonia caused by pneumococcus. Both etiological forms are characterized by a sudden onset with an increase in body temperature to 39 ° C, a rapid increase in intoxication. Against the background of fever, cough, shortness of breath, chest pain appear. Chills are rare. Cough from dry and unproductive soon becomes moist, with the release of mucopurulent sputum. “Rusty sputum” is uncharacteristic. If streptococcal pneumonia is preceded by a viral disease, then the addition of a bacterial infection may indicate a worsening of the course of SARS. Intoxication and respiratory symptoms may be accompanied by the appearance of a scarlet fever-like rash.
A characteristic feature of streptococcal pneumonia is the frequent addition of parapneumonic pleurisy and empyema of the pleura, which occur already on the 2-3 day of the disease. These complications occur in almost 60% of children and 50% of adults. Purulent pericarditis, the formation of pulmonary abscesses in the area of a pneumonic focus is noted somewhat less often (in 35% of patients). Cases of purulent arthritis, osteomyelitis and glomerulonephritis are even rarer.
Separately, streptococcal pneumonia of newborns is isolated, which manifests in the first 5-7 days of a child’s life. Most often it serves as a manifestation of intrauterine sepsis caused by streptococcal infection. Such pneumonia occurs with severe respiratory disorders (tachypnea, dyspnea, episodes of apnea, diffuse cyanosis, increasing hypoxemia).
During the etiological verification of pneumonia, the pulmonologist takes into account the anamnesis (transferred viral and bacterial infections), acute onset, previously the addition of pleurisy. Percussion and auscultative data in streptococcal pneumonia are scarce, which is explained by the small size of pneumonic foci. Meanwhile, in the general blood test from the first days of the disease, there is marked leukocytosis (up to 20-30×109 / l), a shift of the leukocyte formula to the left.
Radiography of the lungs reveals scattered infiltrative shadows, more often in the middle and lower lobes. During the formation of an abscess, a cavity with a horizontal fluid level is determined; the development of pleurisy is indicated by intense homogeneous darkening with an oblique upper border. To establish the nature of the exudate (serous or purulent), a pleural puncture is performed.
Bacteriological sputum culture is an important part of confirming the diagnosis of streptococcal pneumonia. Streptococcus culture can also be isolated from other biological media – blood, pleural exudate. The streptococcal etiology of pneumonia may be indicated by an increase in antistreptolysin-O (ASL-O) titers in the patient’s blood. Differential diagnosis should be carried out with other types of pneumonia (pneumococcal, staphylococcal, atypical, etc.).
Streptococcal pneumonia treatment
The principles of treatment of streptococcal pneumonia do not differ from the main approaches to the treatment of bacterial pneumonia in general. The main links include the appointment of bed rest for the period of fever, antibiotic therapy, detoxification measures, rehabilitation procedures.
The first-line antibiotics for streptococcal pneumonia are penicillins (penicillin G, carbenicillin, ampicillin, amoxicillin), which are often used in combination with aminoglycosides. The second and third-line drugs, respectively, are macrolides and cephalosporins of the 2nd generation. Antibiotics are initially administered parenterally, then after the onset of clinical improvement – inside for 2-3 weeks.
In order to detoxify, correct the water-electrolyte balance and replenish protein losses, intravenous administration of glucose, water-salt solutions, plasma transfusion is carried out. When streptococcal pneumonia is complicated by pleurisy (serous or purulent), repeated thoracocentesis or closed drainage of the pleural cavity with aspiration of exudate and subsequent washing with antiseptics or antibiotics is indicated.
In the late period, after the relief of feverish intoxication syndrome, physiotherapy rehabilitation is prescribed (drug electrophoresis, UHF, inductothermy, microwave therapy, inhalation therapy), chest massage, physical therapy.
Prognosis and prevention
In general, the mortality rate from streptococcal pneumonia is low. Prolonged course of the disease and purulent complications with timely and rational antibiotic therapy are rare. Prevention consists in strengthening the protective functions of the body, rehabilitation of foci of streptococcal infection in the nasopharynx. A measure of specific prevention of complications is vaccination of children and the elderly against pneumococcal infection.