Pneumococcal infection in children

Pneumococcal infections are a group of diseases of bacterial etiology, clinically manifested by purulent-inflammatory changes in various organs and systems, but especially often in the lungs as lobar pneumonia and in the central nervous system as purulent meningitis.

The disease most often occurs in children and adults with a deficiency of humoral immunity.

Infection with pneumococci can occur both exogenously and endogenously. With exogenous infection, lobar pneumonia most often develops. Endogenous infection occurs due to a sharp weakening of the immune defense and the activation of saprophytic pneumococci on the mucous membranes of the respiratory tract. Under these conditions, pneumococci can cause meningitis, septicemia, endocarditis, otitis media, pericarditis, peritonitis, sinusitis and other purulent-septic diseases.

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Epidemiology of pneumococcal infection

Pneumococci are common inhabitants of the human upper respiratory tract and in this sense they can be classified as opportunistic microorganisms.

The source of infection is always a person - a patient or a carrier of pneumococci. The pathogen is transmitted by airborne droplets and contact-household means.

Susceptibility to pneumococci has not been precisely established. The disease usually develops in children with a deficiency of type-specific antibodies and is especially severe in children with sickle cell anemia, other forms of hemoglobinopathy, and deficiency of the complement component C3. It is believed that in these cases the disease develops against the background of incomplete opsonization of pneumococci, which makes their elimination by phagocytosis impossible.

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Causes of pneumococcal infection

According to the modern classification, pneumococci belong to the Streptococcaceae family, Streptococcus genus. These are gram-positive cocci of oval or spherical shape, 0.5-1.25 µm in size, located in pairs, sometimes in short chains. Pneumococci have a well-organized capsule. According to its polysaccharide composition, more than 85 serotypes (serovars) of pneumococci have been identified. Only smooth capsular strains are pathogenic for humans, which, using special serums, are classified as one of the first 8 types; the remaining serovars are weakly pathogenic for humans.

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Pathogenesis of pneumococcal infection

Pneumococci can affect any organs and systems, but the lungs and respiratory tract should be considered a triple organ. The reasons that determine the tropism of pneumococci to the bronchopulmonary system have not been reliably established. It is more likely that the capsular antigens of pneumococci have an affinity for the tissues of the lungs and the epithelium of the respiratory tract. The introduction of the pathogen into the lung tissue is facilitated by acute respiratory infections, which eliminate the protective function of the epithelium of the respiratory tract and reduce the overall immunoreactivity. Various congenital and acquired defects of the bacterial antigen elimination system are also important: defects in the surfactant system of the lung, insufficient phagocytic activity of neutrophils and alveolar macrophages, impaired bronchial patency, decreased cough reflex, etc.

Causes and pathogenesis of pneumococcal infection

Symptoms of pneumococcal infection

Croupous pneumonia (from the English word croup - to croak) is an acute inflammation of the lungs, characterized by the rapid involvement of a lobe of the lung and the adjacent area of the pleura in the process.

The disease is observed mainly in older children. In infants and young children, lobar pneumonia is extremely rare, which is explained by insufficient reactivity and the peculiarities of the anatomical and physiological structure of the lungs (relatively wide intersegmental connective tissue layers that prevent contact spread of the inflammatory process). Lobar pneumonia is most often caused by I, III and especially IV serotypes of pneumococci, other serotypes rarely cause it.

Symptoms of pneumococcal infection

Classification

Depending on the site of the lesion, there are lobar pneumonia, pneumococcal meningitis, otitis media, osteomyelitis, endocarditis, and peritonitis.

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Diagnosis of pneumococcal infection

Pneumococcal infection can be accurately diagnosed only after the pathogen has been isolated from the lesion or blood. Sputum is taken for examination in case of lobar pneumonia, blood in case of suspected sepsis, purulent discharge or inflammatory exudate in case of other diseases. Pathological material is subjected to microscopy. Detection of gram-positive lanceolate diplococci surrounded by a capsule serves as the basis for preliminary diagnosis of pneumococcal infection.

Diagnosis of pneumococcal infection

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Treatment of pneumococcal infection

In severe cases, antibiotics are prescribed.

For mild and moderate forms (nasopharyngitis, bronchitis, otitis, etc.), phenoxymethylpenicillin (vepicombin) can be prescribed at 5,000-100,000 U/kg per day in 4 doses orally or penicillin at the same dose 3 times a day intramuscularly for 5-7 days.

Treatment of pneumococcal infection

• Pneumonia - Treatment regimen and nutrition
• Antibacterial drugs for the treatment of pneumonia
• Pathogenetic treatment of pneumonia
• Symptomatic treatment of pneumonia
• Combating complications of acute pneumonia
• Physiotherapy, exercise therapy, breathing exercises for pneumonia
• Sanatorium and resort treatment and rehabilitation for pneumonia

Prevention of pneumococcal infection

For the prevention of pneumococcal infection, it is proposed to administer the polyvalent polysaccharide vaccine against pneumococcal infection Pneumo-23 by Sanofi Pasteur (France), which is a mixture of purified capsular polysaccharides of 23 most common serotypes of pneumococcus. One dose of such a vaccine contains 25 mcg of each type of polysaccharide, as well as an isotonic solution of sodium chloride and 1.25 mg of phenol as a preservative. The vaccine does not contain other impurities. It is recommended to administer it to children at risk for pneumococcal infection over 2 years old, which include children with immunodeficiencies, asplenia, sickle cell anemia, nephritic syndrome, hemoglobinopathies.

Prevention of pneumococcal infection

Forecast

In pneumococcal meningitis, the mortality rate is about 10-20% (in the pre-antibiotic era - 100%). In other forms of the disease, fatal cases are rare. They occur, as a rule, in children with congenital or acquired immunodeficiency, long-term treatment with immunosuppressive drugs, in children with congenital deformities.

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