Pneumonia

   Pneumonia - an acute infectious inflammatory disease of the lung parenchyma with involvement in the process of all structural elements, mainly respiratory portions of the lungs.   The concept of "pneumonia" does not include lung disease caused by physical and chemical factors, diseases caused by vascular changes and allergies, bronchitis, bronchiolitis, and diffuse pulmonary fibrosis.

   In the structure of lung disease in young children acute pneumonia is about 80%. Until now pneumonia among the 10 most common causes of death. The incidence of pneumonia in different regions of the averages from 4 to 17 cases per 1000 children.

   The classification is based on the pneumonia severity and duration of the disease, as well as X-ray morphological characteristics of its various forms. In the classification into account the etiology of pneumonia terms of infecting the baby, and his premorbid background (immunodeficiency, ventilation, etc.).

• Terms of infecting the baby.

• Community-acquired pneumonia developed in the home, most often as a complication of viral respiratory infections.

• Of Hospital (nosocomial) pneumonia believe, had developed 72 hours after the child's hospitalization and within 72 hours after discharge.

• Intrauterine or congenital, called pneumonia arising in the first 72 hours after birth, evolved at a later date is considered acquired or postnatal.

• Rentgenomorfologicheskim featured on isolated focal, segmental, lobar, and interstitial pneumonia.

• Focal bronchopneumonia characterized by catarrhal inflammation of lung tissue with the formation of fluid in the lumen of the alveoli. Foci size 0.5-1 cm infiltration may be located in one or more segments of the lung, at least - bilaterally. One of the options focal pneumonia - focal and confluent form. In this form of individual sections of infiltration coalesce to form large, heterogeneous density center, which occupies an entire lobe and often has a tendency to destruction.

• Segmental pneumonia (mono-and polysegmentary) are characterized by inflammation of a segment, which has been reduced because of the lightness expressed atelektaticheskogo component. These pneumonia often have a tendency to prolonged duration. The end result could be a protracted pneumonia fibrosis lung tissue and bronchial distortion.

• Lobar pneumonia (pneumococcal usually) different hyperergic lobar inflammation, having cycled during the phases of the tide, red, then white hepatization and resolution. Inflammation has a lobar or sublobarnoe spread with pleural involvement in the process.

• Acute interstitial pneumonia is characterized by the development of plasma or mononuclear cell infiltration and proliferation of interstitial lung tissue of focal or widespread nature. Such pneumonia most often lead to certain pathogens (viruses, Pneumocystis, fungi, etc.).

• According to clinical manifestations release not heavy (uncomplicated) and severe (complicated) form of pneumonia. The severity of the latter may be due to the development of a toxic syndrome, respiratory failure, cardiovascular disorders, pulmonary edema, pulmonary tissue destruction, the emergence of pleurisy or extrapulmonary septic foci, etc. Pneumonia can have an acute and prolonged duration.

• If the acute course of clinical and radiological resolution of pneumonia occurs within 4-6 weeks from the onset.

• The average duration of protracted pneumonia - 2-4 months or more (up to 6 months), after which, with adequate treatment, recovery occurs.

The causes of pneumonia

    Causative agents of pneumonia are diverse: viruses, bacteria, pathogenic fungi, protozoa, mycoplasma, chlamydia, and other microorganisms, which often form the association.   Viral infection often plays the role of a factor in the emergence of pneumonia. However, in young children, especially in neonates and premature, an independent etiological significance in the development of pneumonia during seasonal epidemics of influenza viruses may have, parainfluenza, respiratory syncytial virus. In congenital cytomegalovirus pneumonia is often diagnosed interstitial processes. Recorded and early measles pneumonia.   Etiology pneumonia depends substantially on the conditions of its occurrence (home, hospital, etc.), as well as the age of the child, so these factors should be carefully considered when assigning antibiotic therapy.

    Pneumonia in infants usually develop as a result of intrauterine infection and nosocomial group B streptococci, Escherichia coli, Klebsiella, Staphylococcus aureus. Often diagnosed pneumonia caused by herpes viruses (cytomegalovirus, herpes simplex virus types 1 and 2). Community-acquired pneumonia in children under 6 months of life is most often caused by gram-negative intestinal flora and staphylococci. The main causative agent of atypical pneumonia that occur with normal or low grade temperature, - Chlamydia trachomatis, infecting children intrapartum, and manifests in 1.5-2 months. Premature children and immunocompromised pneumonia can be caused by pathogenic microflora and protozoa (eg, Pneumocystis carinii).

    In children older than 6 months predominant causative agent of community-acquired pneumonia - pneumococcus (35-50%). Less commonly (7-10%), Haemophilus influenzae disease and cause of the family Neisseriaceae (eg, Moraxella catarrhalis). The children of school age pneumonia caused by Haemophilus influenzae, almost there, but increases the frequency of atypical pneumonia caused by Mycoplasma pneumoniae and Chlamydia pneumoniae. The leading role in the occurrence of nosocomial pneumonia belongs to Gram negative (Escherichia coli, Proteus, Klebsiella pneumoniae, Enterobacter, Pseudomonas aeruginosa), Staphylococcus aureus less frequently. Hospital flora is often resistant to most antibiotics used. Nosocomial pneumonia is the most serious course and outcome.

    Pathogenic flora in children with immunodeficiency depends on its type and in violation of the process of cell-mediated immunity in the lung may be caused not only common, but also opportunistic pathogens (Pneumocystis carinii, Candida albicans), and viruses. If you violate the primary humoral immunity more likely to cause pneumococcal pneumonia, staphylococci and gram-negative enterobacteria.

    Pneumonia developing in children on mechanical ventilation at the beginning are associated with autoflora, which quickly gives way to hospital strains of bacteria. 

Pathogenesis

 The main route of infection in the lungs - aerogenic. Pathogens entering the respiratory tract, spread it in the respiratory parts of the lungs, aided by the earlier SARS. Viruses infecting the respiratory tract mucosa, violate the protective barrier function of the epithelium and mucociliary clearance. Excess production of mucus in the upper respiratory tract protects organisms from the bactericidal action of bronchial secretions, facilitating their penetration into the terminal respiratory bronchioles. Here microorganisms rapidly multiply and cause inflammation involving the adjacent areas of the lung parenchyma. The formation of the inflammatory focus in the lungs contribute to the disruption of bronchial patency and development gipopnevmatozov. Impaired patency of bronchial microcirculation disorders, inflammatory infiltration, interstitial edema and reduced lightness lung parenchyma leads to a violation of the diffusion of gases and hypoxemia. Last accompanied by respiratory acidosis, hypercapnia, dyspnea and compensatory onset of clinical signs of respiratory distress and hypoxia. Pneumonia in children is often accompanied not only respiratory, but also cardiovascular failure resulting from circulatory disorders, overloading of the pulmonary circulation, metabolic-dystrophic changes in the myocardium. 

The clinical picture

    The most common general symptoms of pneumonia - fever to febrile values ​​(above 38 ° C), kept more than 3 days (in the absence of treatment), and signs of intoxication (pale, grayish skin with marble pattern, lethargy, sleep and eating disorders). Infants often appear regurgitation and vomiting.

   Respiratory (lung) symptoms may be represented by shortness of breath, wet, sometimes dry cough, cyanosis nasolabial triangle and grunting with severe forms of the disease. However, all these signs are unstable.

   Shortening the percussion sound on a separate plot of the lung, strengthening bronhofonii, the changing nature of breathing (more attenuation) and local small bubbling rales or crackles in the same place can make a diagnosis of pneumonia by clinical data. However, to discover these local features is not always possible (only in 60-80% of patients). The absence of local symptoms of lung disease in the presence of general toxic, inflammatory and "respiratory" symptoms did not rule out the diagnosis of acute pneumonia!

   Additional methods of research reveals typical pneumonia changes in blood inflammatory (neutrophilic leukocytosis with a shift to the left in the leucocyte count, increased erythrocyte sedimentation rate). The x-ray, depending on the nature of lung disease or interstitial infiltrates detected changes.

   The clinical picture depends on the form of pneumonia severity and characteristics of the pathogen causing the disease. However, to determine the etiology of pneumonia solely on clinical signs is very difficult and often impossible.