Diagnosis of pneumonia in children
Last reviewed: 23.04.2024
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Laboratory Diagnosis of Pneumonia
The analysis of peripheral blood should be performed by all patients with suspected pneumonia. Leukocytosis more than 10-12x10 9 / l and a stab shift of more than 10% indicate a high probability of bacterial pneumonia. With the diagnosis of pneumonia, leukopenia less than 3 × 10 9 / L or leukocytosis more than 25 × 10 9 / L is considered unfavorable prognostic signs.
Biochemical analysis of blood and the study of the acid-base state of blood are standard methods for examining children and adolescents with severe pneumonia. In need of hospitalization. Determine the activity of liver enzymes, the level of creatinine and urea, electrolytes.
Etiological diagnosis is established mainly in severe pneumonia. Perform a blood culture, which gives a positive result in 10-40% of cases. The microbiological examination of sputum in pediatrics is not widely used due to the technical difficulties of sampling sputum in the first 7-10 years of life. But in cases of bronchoscopy, a microbiological study is used, aspirates from the nasopharynx, tracheostomy and endotracheal tube serve as material for it. In addition, to identify the pathogen, puncture the pleural cavity and sow the punctate pleural contents.
Serological methods of research are also used to determine the etiology of the disease. The growth of titres of specific antibodies in paired sera taken in the acute period and the period of convalescence. May indicate a mycoplasmal or chlamydial etiology of pneumonia. Reliable methods are also considered detection of antigens by latex agglutination methods, counter immunoelectrophoresis, ELISA. PCR, etc. All these methods, however, take time, do not affect the choice of treatment tactics and have only epidemiological significance.
Instrumental methods of diagnosing pneumonia
The "Golden Standard" for the diagnosis of pneumonia in children is chest X-ray examination, which is considered a highly informative and specific diagnostic method (the specificity of the method is 92%). When analyzing the radiographs, the following indicators are evaluated:
- the sizes of infiltration of lungs and its prevalence;
- presence or absence of pleural effusion;
- presence or absence of destruction of the pulmonary parenchyma.
All these data help determine the severity of the disease and correctly choose antibiotic therapy. Subsequently, with a distinct positive dynamics of clinical manifestations of community-acquired pneumonia, there is no need for control radiography (at hospital discharge or when the child is treated at home). It is more expedient to carry out the control radiography not earlier than in 4-5 weeks from the onset of the disease.
Radiography in dynamics in the acute period of the disease is carried out only if there is a progression of symptoms of lung damage or when signs of destruction and / or involvement of the pleura in the inflammatory process appear. In cases of a complicated course of pneumonia, mandatory radiographic monitoring is performed before the patient is discharged from the hospital.
In hospital pneumonia, it must be remembered that if pneumonia develops 48 hours before the death, then the radiographic examination can give a negative result. Such x-ray negative pneumonia (when the radiography, conducted 5-48 hours before the patient's death, did not detect pneumonic infiltration in the lungs) is observed in 15-30% of cases. Diagnosis is established only clinically on the basis of pronounced respiratory failure, weakened breathing; there can often be a brief rise in temperature.
Radiographic study in the dynamics of hospital pneumonia in the acute period of the disease is performed with the progression of symptoms of lung damage or with the appearance of signs of destruction and / or involvement of the pleura in the inflammatory process. With a distinct positive dynamics of clinical manifestations of pneumonia, control radiography is performed at discharge from the hospital.
When assessing the condition of children and children with severe community-acquired pneumonia previously hospitalized for any pathology, special attention should be given to the state and effectiveness of the respiratory function, in particular pulsoximetry. In case of severe pneumonia and hospital pneumonia, especially VAP, monitoring of such parameters as breathing rate, pulse rate, arterial pressure, acid-base state, diuresis, and body weight are necessary for children of the first half of the year.
Computed tomography (CT) is used, if necessary, for differential diagnosis, since CT has a 2-fold higher sensitivity than survey radiographs in detecting infiltration sites in the lower and upper lobes of the lungs.
Fibroblochoscopy and other invasive techniques are used to obtain material for microbiological examination in patients with severe immunity disorders and in differential diagnosis.
Differential diagnosis of pneumonia in children
When conducting differential diagnosis, it is necessary to take into account the age of the child, since in different age periods the pathological processes in the lungs have their own peculiarities.
In infancy, the clinical picture of respiratory failure may be due to conditions such as aspiration, foreign body in the bronchi, previously untreated tracheoesophageal fistula, gastroesophageal reflux, developmental defects of the lungs (fractional emphysema), heart and large vessels, cystic fibrosis and a-antitrypsin deficiency. Children of the second and third years of life and in the older age (up to 6-7 years) should exclude the Kartagener syndrome; hemosiderosis of the lungs; nonspecific alveolitis; selective IgA deficiency.
Differential diagnosis at this age should be based on the use (in addition to lung radiography and peripheral blood analysis) of the endoscopic examination of the trachea and bronchi, lung scintigraphy, angiography, conduction of sweat and other samples for cystic fibrosis, determination of the concentration of a-antitrypsin, study of the blood immunogram and other research.
At any age it is necessary to exclude tuberculosis of the lungs. In the absence of positive dynamics of the process within 3-5 days (maximum 7 days) of therapy, prolonged course of community-acquired pneumonia, its resistance to ongoing therapy, it is necessary to expand the survey plan for identifying atypical pathogens (S. psittaci, Ps. Aerugenozae, Leptospira, Coxiella burneti). and for the diagnosis of other lung diseases.
In patients with severe immunity defects in the appearance of dyspnea and focal-infiltrative changes on the chest radiograph, it is necessary to exclude the involvement of the lungs in the main pathological process (for example, in systemic connective tissue diseases), as well as lung damage as a consequence of the therapy (lung medication, radiation pneumonitis .).
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