Differential diagnosis of pneumonia

Pulmonary tuberculosis

Regardless of the clinical variant of pneumonia and the form of pulmonary tuberculosis, differential diagnostics between these diseases requires, first of all, the use of well-known methods for diagnosing pulmonary tuberculosis as a nosological unit.

Analysis of anamnesis data

Assuming that the patient has tuberculosis, the following anamnestic data allow:

• presence of tuberculosis in the patient's family;
• previously suffered from tuberculosis of any localization;
• ascertaining the course of the disease. An acute onset and severe course are observed in acute miliary pulmonary tuberculosis and caseous pneumonia, with the remaining forms of tuberculosis, the onset of the disease is usually gradual, often completely unnoticeable. Acute lobar pneumonia has an acute onset, focal pneumonia begins gradually, but the duration of the initial period is, of course, significantly less than with pulmonary tuberculosis;
• information about previous illnesses. Diseases such as exudative pleurisy, often repeated fibrinous (dry) pleurisy, prolonged subfebrile condition of unknown origin and unexplained malaise, sweating, weight loss, prolonged coughing (especially if the patient does not smoke) with hemoptysis may be manifestations of pulmonary tuberculosis.

Analysis of external examination data of patients

About the previously transferred tuberculosis may be indicative of irregularly shaped scars in the region of previously affected cervical lymph nodes, about the spinal tuberculosis that once took place-kyphosis.

Rapidly evolving severe intoxication and a severe condition of the patient are more characteristic of shared or total pneumonia and are not characteristic for tuberculosis, with the exception of acute miliary tuberculosis and caseous pneumonia.

Analysis of physical findings from lung examination

Unfortunately, there are no physical symptoms, absolutely pathognomonic for pulmonary tuberculosis. Data such as changes in vocal tremor, bronchophoria, bronchial breathing, crepitation, wet and dry rales, and pleural friction noise can be observed in pulmonary tuberculosis and in non-specific lung diseases, including pneumonia.

However, the following features of the physical data characteristic of pulmonary tuberculosis may have some diagnostic value:

• localization of pathological percussion and auscultative phenomena mainly in the upper parts of the lungs (of course, this is not an absolute rule);
• the scarcity of physical data in comparison with the data of X-ray research (the aphorism of the old doctors "is not audible, but it is much visible in pulmonary tuberculosis and is heard a lot, but it is not very visible with non-tubercular pneumonia"). Of course, this pattern does not apply to all forms of tuberculosis, but can be observed with focal, miliary tuberculosis, tuberculoma.

Staging of tuberculin samples

The setting of tuberculin samples (tuberculin diagnostics) is based on the definition of tuberculin allergy - an increased sensitivity of the body to tuberculin, caused by infection with virulent mycobacteria tuberculosis or vaccination with BCG.

The most commonly used intradermal Mantoux test, with 0.1 ml of tuberculin injected into the skin of the inner surface of the middle third of the forearm. The results of the test are evaluated after 72 hours, measuring the diameter of the papule with a transparent millimeter ruler. Record the diameter of the papule (relative to the axis of the arm); the reaction is considered negative with a papule diameter from 0 to 1 mm, questionable at a diameter of 2-4 mm, positive - with a diameter of 5 mm or more, hyperergic - at a diameter of 17 mm or more in children and adolescents and 21 mm or more in adults . Hyperergic also include vesicular necrotic reactions, regardless of the size of the infiltrate.

A positive and especially hyperergic tuberculin test may indicate the presence of pulmonary tuberculosis. However, the final diagnosis of pulmonary tuberculosis is made only on the basis of a comprehensive clinical, laboratory and radiographic examination of the patient, and, of course, the results of tuberculin samples are taken into account.

Microbiological diagnosis of tuberculosis

The definition of mycobacteria tuberculosis in sputum, bronchial flushing fluid, in pleural exudate is the most important method of diagnosing tuberculosis. Classical microbiological methods are used: bacterioscopy, culture or culture, a biological test on laboratory animals susceptible to tuberculosis infection.

Sputum analysis is one of the main and most common methods. To increase the sensitivity of the method, a flotation method is used in which the mycobacteria are extracted from the aqueous sputum suspension using fluids with a relative density less than water (xylene, toluene, benzene, benzene). In this case, the frequency of detection of mycobacteria increases by no less than 10% compared to conventional microscopy.

Smears are prepared from native sputum. The color is produced by the Tsilya-Nilsson method. Mycobacteria are found in the preparation in the form of thin straight or slightly curved bright red sticks.

In recent years, the method of luminescence microscopy has been applied. The method is based on the ability of lipids of mycobacteria to perceive luminescent dyes and then to glow when irradiated with ultraviolet rays. Mycobacterium tuberculosis in luminescent microscopy gives a bright red or luminescent-yellow glow on a green background (depending on the type of dye). Luminescent microscopy significantly increases the effectiveness of the bacterioscopic method of detecting mycobacteria tuberculosis.

The method of inoculation (the culture method for the detection of mycobacteria tuberculosis) is more sensitive than bacterioscopic. It detects mycobacterium tuberculosis in sputum, with 1 liter of its several dozen viable individuals. Various nutrient media are used for the cultivation of mycobacterium tuberculosis. WHO experts recommend the Levenstein-Jensen medium (dense egg medium) as the standard medium for primary excretory excretion in which a good growth of mycobacterium tuberculosis is obtained 15-25 days after planting a bacterioscopically positive material.

When a bacterioscopically negative material (sputum) is sown on dense nutrient media, the average duration of growth of mycobacteria is 20-46 days, however, individual strains can grow up to 60-90 days. That is why it is necessary to maintain sputum culture in a thermostat for at least 3 months. Then a microscopy of the smear from the grown colonies, colored according to Tsiol-Nielsen, is performed. Mycobacterium tuberculosis is detected in the form of bright red or dark red sticks.

Biological assay is the most sensitive method for detecting mycobacterium tuberculosis. It is used with negative results of bacterioscopy and sputum culture, but with a continuing suspicion of tuberculosis. The test consists in the introduction of guinea pig specially treated sputum of the patient. Then the pig is slaughtered after 3 months and with a positive result of the biological test, morphological signs of tuberculosis in the organs and tissues are found. At the time of the autopsy, they make smear-prints from the organs for bacterioscopy studies. In the absence of macroscopic signs of tuberculosis in the organs, a culture is taken from the lymph nodes, spleen, liver, lungs and specially processed material on dense nutrient media.

The biological method is relatively rarely used due to its laboriousness.

X-ray examination of the lungs

In the diagnosis of pulmonary tuberculosis, the leading role belongs to the radiographic methods of investigation. L. I. Dmitrieva (1996) suggests using them as follows:

• mandatory radiographic diagnostic minimum (large-frame fluorography, review radiography);
• in-depth X-ray examination (radiography in two mutually perpendicular projections, fluoroscopy, standard tomography);
• additional X-ray examination (various methods of radiography and tomography, including computer and magnetic resonance imaging).

The characteristic X-ray manifestations of individual forms of pulmonary tuberculosis are presented below.

Focal pulmonary tuberculosis

Focal pulmonary tuberculosis is a clinical form characterized by a limited inflammatory process (focal size about 10 mm) and a low-symptom clinical course. The main clinical features of focal pulmonary tuberculosis are the following:

• a prolonged chronic undulating course with a change in the phases of exacerbation and remission. For acute pneumonia such a course is not typical;
• absence of bright clinical manifestations even in the phase of exacerbation, and even more so in the phase of compaction; with pneumonia, as a rule, the symptom of intoxication is expressed significantly, especially with lobar pneumonia;
• characteristic long cough without discharge or with the release of a small amount of sputum (even if the patient is not a smoker);
• listening to small bubbling rales in a restricted area of the lung and, as a rule, after coughing;
• characteristic radiographic picture.

X-ray manifestations of focal pulmonary tuberculosis can be divided into three main groups):

• fresh forms differ in unsharply outlined foci of various shapes and sizes, sometimes merging with a background of pronounced lymphangitis;
• subacute forms are characterized by more sharply outlined foci due to pronounced productive changes;
• fibro-indurative changes with predominance of linear cords over focal shadows.

With exacerbation of focal tuberculosis around the old foci, a zone of perifocal inflammation appears and possible development of new foci against the background of dense old foci.

Infiltrative pulmonary tuberculosis

Infiltrative pulmonary tuberculosis is a clinical form characterized mainly by an exudative type of inflammatory process with a tendency to rapid formation of caseous necrosis and destruction.

TB infiltrates are small in size (diameter from 1.5 to 3 cm), medium (3 to 5 cm) and large (more than 5 cm).

Clinical symptoms in infiltrative pulmonary tuberculosis are determined by the magnitude of the lesion and the phase of the process.

The following clinical x-ray variants of infiltrative pulmonary tuberculosis are distinguished:

• Cloud-like variant - characterized by a gentle, non-intensive homogeneous shadow with fuzzy outlines. At the same time, the formation of a disintegration and a fresh cavern is possible;
• a round variant - is shown by a round homogenous weak-intensive shadow with precise contours, the diameter of the shadow is more than 10 mm;
• lobit - the infiltrative process affects the entire share, the shadow is inhomogeneous with the presence of cavities of decay;
• periscissuritis - a vast infiltrate localized at interlobar crevices and often causing inter-pediatric pleurisy, while the shadow on one side has a clear contour, on the other - its outlines are blurred;
• lobular variant - is characterized by an inhomogeneous shadow formed due to the fusion of large and small foci.

To differentiate infiltrative pulmonary tuberculosis and acute pneumonia by clinical signs is very difficult, as there is a great similarity in the clinical manifestations of both these diseases. As a rule, infiltrative tuberculosis, like acute pneumonia, proceeds with a high body temperature, expressed by symptoms of intoxication, the physical data are also similar. However, unlike pneumonia with infiltrative tuberculosis, hemoptysis is much more common. Very rarely, a tuberculous infiltrate is asymptomatic or asymptomatic. In the diagnosis of infiltrative pulmonary tuberculosis, a radiological examination of the lungs, a sharply positive tuberculin test, determination of mycobacteria in sputum, a clear positive effect of antituberculous therapy acquire the leading role.

In addition, it should be noted that for all clinical and x-ray variants of infiltrative tuberculosis is characterized not only the presence of infiltrative shade, but also bronchogenic seeding in the form of fresh foci both in the lung, in which there is an infiltrate, and in the second lung. Quite often, with a tuberculous infiltrate, there is a "pathway" from the infiltrate to the lung root, caused by inflammatory peribronchial and perivascular changes (this is clearly seen on radiographs). Finally, it should be taken into account that, although the tuberculous infiltrate may be located in any part of the lung, it is most often localized in the region of the second bronchopulmonary segment and is most often detected in the lateral zone of the subclavian region on the anterior radiograph.

Caseous pneumonia

Caseous pneumonia is a clinical form of pulmonary tuberculosis characterized by pronounced exudative inflammation of the entire lobe of the lung or most of it, which is quickly replaced by caseous-necrotic changes ("curdled" decay) followed by the formation of caverns. The course of caseous pneumonia is severe.

Miliary tuberculosis of the lungs

Miliary tuberculosis of the lungs is the dissemination of the tuberculosis process with the formation of small foci (1-2 mm) with a predominantly productive reaction, although case-necrotic changes are also possible. The disease begins sharply, the body temperature rises to 39-40 ° C, the intoxication syndrome is expressed dramatically, the patients are disturbed by pronounced weakness, sweating (possible debilitating night sweats), anorexia, weight loss, shortness of breath, persistent dry cough. With percussion of the lungs, there is no significant change in percussion sound, while auscultation of the lungs can listen to a small number of dry wheezes in connection with the development of the bronchiolitis. Thus, there is some similarity in the clinical manifestations of severe pneumonia and miliary pulmonary tuberculosis.

Disseminated tuberculosis of the lungs

Disseminated pulmonary tuberculosis is a clinical form characterized by the formation of a multitude of tuberculosis foci. With the flow, acute, subacute and chronic forms of disseminated pulmonary tuberculosis are distinguished. Acute and subacute forms are characterized by severe course, patients have high body temperature, chills, night sweats, a very toxic intoxication syndrome, coughing, usually dry, less often with sputum. Excess short breath can develop. With auscultation of the lungs you can listen to small bubbling rales, crepitation in the upper and middle sections. The main diagnostic method is radiological.

With acute disseminated tuberculosis, focal shadows are determined in the lungs, evenly distributed from the tips to the diaphragm - a pattern of dense dissemination of small and medium-sized soft foci.

When subacute disseminated tuberculosis is characterized by the appearance of larger soft foci, merging with each other. The foci are prone to decay, rapid formation of caverns.

Chronic disseminated tuberculosis of the lungs usually develops imperceptibly, the clinical course of its prolonged, periodic dissemination of the process in the lungs may not give a clear clinical picture or proceed under the guise of pneumonia, exacerbation of chronic bronchitis. Often develops fibrinous or exudative pleurisy. Physical data for chronic disseminated pulmonary tuberculosis are meager: it is possible to detect a shortening of percussion sound, mainly in the upper parts of the lungs, severe vesicular breathing, sometimes small bubbles or single dry wheezing (in connection with bronchial lesions) can be heard under the areas of blunting. Chronic disseminated tuberculosis of the lungs, both acute and subacute, can be complicated by the decay and formation of a cavity. In this case, the tetrad of symptoms is characteristic: cough with sputum separation, hemoptysis, wet wheezing, mycobacterium tuberculosis in sputum.

Progression of the process in chronic disseminated pulmonary tuberculosis leads to increased development of fibrosis and cirrhosis of the lungs.

Thus, disseminated pulmonary tuberculosis is difficult to distinguish from pneumonia. A decisive role in diagnosis belongs to the X-ray method of investigation.

The main radiographic signs of disseminated pulmonary tuberculosis are (Μ. Lomako, 1978):

• two-sided destruction;
• polymorphism of focal shadows;
• alternation of clearly defined foci with fresh, poorly contoured foci;
• localization of foci in the upper posterior parts (1-2 segments);
• different size of the foci in different parts of the lungs: in the upper parts foci are larger, with distinct contours and even the presence of calcareous inclusions; in the lower parts foci of smaller dimensions with more diffuse contours;
• symmetrical location of foci in both lungs with acute, asymmetric - with chronic disseminated pulmonary tuberculosis;
• the appearance of cavity decay during the progression of the process;
• progressive development of fibrosis and cirrhosis.

Differential diagnosis of pneumonia, pulmonary tuberculosis, cavernous and fibrous-cavernous pulmonary tuberculosis is simple in that these forms of tuberculosis have clear radiological manifestations.

Tuberculoma is an isolated and encapsulated by a connective tissue curdled necrotic focus of round form more than 1 cm in diameter.

In the X-ray image, tuberculoma looks like a clearly defined formation of a homogeneous or heterogeneous structure against the background of the intact lung. It is localized mainly in 1-2, 6 segments. Its shape is round, the edges are even. For the most part, tuberculoma has a homogeneous structure. However, in a number of cases its structure is heterogeneous, which is due to calcifications, foci of enlightenment, fibrotic changes.

The most important differential diagnostic feature, not characteristic for pneumonia, is the presence of a double path in tuberculoma, which runs from tuberculoma to the root of the lung. This path is caused by a tight peribronchial and perivascular infiltration. Often around tuberculomas a capsule is revealed. In the lung tissue around the tuberculoma can be found focal shadows. During the exacerbation of the tuberculosis process, the radiological image of tuberculoma is less clear than in the phase of remission, even a foci of decay may appear. With the progressing course of tuberculoma, with the development of communication between it and the draining bronchus, mycobacterium tuberculosis may appear in the sputum.

Tuberculoma is sometimes difficult to distinguish from peripheral lung cancer. The most reliable method of diagnosing tuberculomas is bronchoscopy with biopsy followed by cytological and bacteriological research.

Exudative pleurisy

The need for differential diagnosis of pneumonia with exudative pleurisy is caused by a certain similarity in the symptoms of both diseases - the presence of dyspnea, symptoms of intoxication, increased body temperature, blunt percussion sound on the side of the lesion. The main distinguishing features are the following:

• much more pronounced lag in the respiration of the corresponding half of the chest in exudative pleurisy than with pneumonia;
• a greater intensity of blunt sound with percussion in exudative pleurisy than with longitudinal pneumonia. Stupidity percussion sound in exudative pleurisy is considered absolute ("femoral"), it grows considerably downwards, percussion finger-pletsimeter feels resistance. With pneumonia, the percussion sound intensity is less;
• absence of auscultatory phenomena over the zone of stupidity (there is no vesicular and bronchial breathing, voice trembling, bronhophonia);
• intense dense homogeneous obscuration with the upper oblique boundary during radiographic examination of the lungs, displacement of the mediastinum to a healthy side;
• Detection of fluid in the pleural cavity by ultrasound and pleural puncture.

Lung infarction

Infarction of the lung occurs due to pulmonary embolism. The main signs that distinguish it from pneumonia are:

• the appearance at the beginning of the disease of intense pain in the chest and shortness of breath, then - an increase in body temperature; with lobar pneumonia, the relationship of pain and increase in body temperature is reversed: as a rule, a sudden increase in body temperature, chills; then there is pain in the chest, sometimes with pneumonia, there is a simultaneous increase in body temperature and chest pain;
• no significant intoxication at the onset of pulmonary embolism;
• hemoptysis is a common sign of a lung infarction; however, it can also be observed with pneumonia, but with a mild infarction, almost pure red blood is excreted, and with pneumonia, mucus is purulent-purulent with an admixture of blood (or "rusty sputum");
• a smaller area of the lung lesion (usually less than the fraction), in contrast to, for example, a fractional lesion in pneumococcal pneumonia;
• a sharp decrease in isotope accumulation in the infarction zone (due to a sharp violation of capillary blood flow) with radioisotope scanning of the lungs;
• characteristic changes in the ECG, suddenly appearing - deviation of the electric axis of the heart to the right, overload of the right atrium (high acute prong of the 2nd and 3rd standard leads in the lead aVF), turning the heart around the longitudinal axis clockwise with the right ventricle forward (the appearance of a deep tooth 5 in all thoracic leads). These ECG changes can also be observed in acute lobar pneumonia, but they are much less pronounced and less frequent;
• presence of thrombophlebitis of the veins of the lower extremities;
• characteristic radiographic changes - bulging of the cone a.pulmonalis, the foci of blackout has the shape of a band, more rarely a triangle with the apex directed towards the root of the lung.

Lungs' cancer

Lung cancer is a common disease. From 1985 to 2000, the number of patients with lung cancer will increase by 44%, and mortality - by 34.4%. The following methods are used to diagnose lung cancer.

Analysis of anamnesis data

Lung cancer is more common in men, especially over the age of 50. As a rule, they abstain from smoking for a long time. Many patients have occupational hazards contributing to the development of lung cancer: work with carcinogenic chemicals, compounds of nickel, cobalt, chromium, iron oxides, sulfur compounds, radioactive substances, asbestos, radon, etc. Significant importance in the diagnosis of lung cancer has the appearance of such symptoms as a persistent cough, change in the tone of voice, the appearance of blood in the sputum, fever, lack of appetite, weight loss, chest pain. The significance of these anamnestic data is even greater if they are combined with the deformity or indistinctness of the lung root, first detected by roentgenologic examination.

X-ray examination of the lungs

Peripheral lung cancer develops from the epithelium of the small bronchi or from the epithelium of the alveoli and can be located in any segment (segment) of the lung. However, most often it is localized in the anterior segments of the upper lobes of the lungs.

X-ray manifestations of peripheral cancer largely depend on the size of the tumor. X-ray signs of peripheral lung cancer can be characterized as follows:

• a tumor of small size (up to 1-2 cm in diameter), as a rule, is manifested by a foci of darkening irregular round, polygonal shape; cancer of medium and large size has a more regular spherical shape;
• The intensity of the shadow of a cancerous tumor depends on its size. When the diameter of the node is up to 2 cm, the shadow has a small intensity, with a larger diameter of the tumor, its intensity increases significantly;
• very often the shadow of the tumor has an inhomogeneous character, which is due to the uneven growth of the tumor, the presence in it of several tumor nodules. This is especially noticeable in tumors of large size;
• the contours of tumor dimming depend on the phase of development of the tumor. A tumor up to 2 cm in size has an irregular polygonal shape and fuzzy outlines. With tumor sizes up to 2.5-3 cm, the blackout has a spherical shape, the contours become radiant. At 3-3.5 cm in diameter, the contours of the tumor become more distinct, however, with the further growth of peripheral cancer, the sharpness of the contours disappears, the tuberosity of the tumor is clearly visible, sometimes cavities of decay are determined in it;
• characteristic is the symptom of Riegler - the presence of cuttings along the contour of the tumor, which is due to the uneven growth of cancer;
• quite often in peripheral lung cancer, a "pathway" to the lung's root is visible, due to lymphangitis, peribronchial and perivascular growth of the tumor;
• X-ray examination in dynamics reveals the progressive growth of the tumor. According to VA Normantovich (1998), in 37% of patients the tumor doubling occurs within 17-80 days; in 43% of patients - 81-160 days, in 20% of cases - 161-256 days;
• in far-reaching cases, the tumor compresses the corresponding bronchus, and the atelectasis of the lobe of the lung develops.

More detailed X-ray signs of cancer and compression of the bronchus are detected using X-ray tomography and computed tomography of the lung.

In the differential diagnosis of acute pneumonia and peripheral lung cancer, the following circumstances must be taken into account:

• in acute pneumonia, under the influence of rational antibacterial therapy, positive dynamics appears rather quickly-a decrease in severity and then a complete disappearance of the foci of darkening; with cancer of similar dynamics is not observed;
• for acute pneumonia is characterized by a positive symptom Fleischnera - good visibility of small bronchi against a background of blackout; this sign is not observed in lung cancer;

Central cancer of the upper lobe and mid-lobe bronchi is manifested by darkening the entire lobe or segment with a decrease in the volume of the lobe. With X-ray tomography, the symptom of the stump of the lobar bronchus is determined. Cancer of the main bronchus is characterized by varying severity of its stenosis up to complete stenosis with the development of atelectasis of the entire lobe of the lung. The stenosis of large bronchi is well revealed in X-ray tomography and computed tomography.

An important diagnostic method is a bronchographic examination that reveals an abruption ("amputation") of the bronchus when the tumor overlaps its lumen.

Bronchoscopy

Bronchoscopy with multiple biopsies of the bronchial mucosa is of great importance in the diagnosis of lung cancer. During bronchoscopy, you can identify direct signs of lung cancer: endobronchial, endophytic or exophytic tumor growth, infiltrative changes in the bronchial wall. A tumor that grows peribronhially, manifests indirect signs: protrusion, rigidity of the bronchus wall, looseness of the mucous membrane, indistinctness of the pattern of the cartilaginous rings of the lobar and segmental bronchi. Along with a biopsy of the bronchial mucosa, flushing of the bronchus is performed followed by a cytological examination of flushing.

In 1982, Kinsley et al. Described a method of fibrobronchoscopy with simultaneous ultraviolet irradiation of the bronchial mucosa. The method is based on the fact that bronchogenic cancer cells have the property of selectively accumulating the hematoporphyrin derivative in comparison with healthy tissues and then fluorescing in ultraviolet rays. Using this technique, the fibroblochoscope is provided with a special source of ultraviolet radiation, a lightguide, a filter, and a focused image amplifier.

In a number of cases, bronchoscopy produces a transbronchial puncture biopsy of a lymph node suspicious in terms of metastasis.

Sputum cytology

It is necessary to test sputum for cancer cells at least 5 times. Cancer cells can be detected in sputum in 50-85% of patients with central and in 30-60% of patients with peripheral lung cancer.

Cytological examination of pleural exudate

The appearance of exudative pleurisy with lung cancer testifies to the far-gone tumor process. Pleural fluid in this case often has a hemorrhagic character, with its cytological examination, tumor cells are detected.

Puncture biopsy of palpable peripheral lymph nodes

Palpable peripheral lymph nodes (cervical, axillary, etc.) indicate metastasis of lung cancer. Puncture biopsy of these lymph nodes provides verification of cancer metastasis in 60-70% of patients.

Immunological methods of diagnosis

Immunological methods for diagnosing cancer have not yet been widely used clinically. However, according to the literature, in the complex diagnosis of lung cancer, the detection in the blood of tumor markers: cancer-embryonic antigen, tissue polypeptide antigen, lipid-bound sialic acids, can have a certain diagnostic value. It should take into account the nonspecificity of these tumor markers, they can be found in the blood in cancer of other organs (liver, stomach, etc.).

Transthoracic puncture

Transthoracic puncture is performed under X-ray television control and is the main method of verifying the diagnosis of peripheral cancer, confirming the diagnosis in 65-70% of cases.

Acute appendicitis

The need for differential diagnosis of acute appendicitis and pneumonia occurs when it is located in the lower lobe of the right lung. This is more common in children. Right-sided lower-lobe pneumonia is often accompanied by pain and muscle tension in the right half of the abdomen, including in the right ileal region.

The main differential-diagnostic differences in right-sided low-grade pneumonia and acute appendicitis are as follows:

• with pneumonia, pain in the right ileal region does not increase when the arm moves inward when palpation of the abdomen; with acute appendicitis - the pain sharply increases, at the same time the tension of the abdominal muscles increases;
• when pneumonia pain increases with breathing, with acute appendicitis this connection is not characteristic or little expressed; However, when coughing, abdominal pain increases both with pneumonia and with acute appendicitis;
• with acute appendicitis, the temperature in the rectum is much higher than the temperature in the axillary region (the difference exceeds the HS), with acute pneumonia there is no such regularity;
• careful percussion and auscultation, radiologic examination of the lungs reveal the symptoms of acute pneumonia in the lower lobe of the right lung, which serves as the main criterion for differential diagnosis.

Cardiogenic pulmonary edema

The need for differential diagnosis of pneumonia and cardiogenic pulmonary edema ("congestive lung") is explained by the presence of similar symptoms: cough with sputum (sometimes with a trace of blood), dyspnoea, crepitus and small bubbling rales in the lower parts of the lungs. Differential-diagnostic differences are the following:

• the presence in patients with "congestive lungs" of symptomatic decompensated cardiac diseases (heart defects, postinfarction cardiosclerosis, severe arterial hypertension, diffuse myocarditis, exudative pericarditis, etc.);
• with "stagnant lungs", as a rule, an increase in the size of the heart, more frequent atrial fibrillation, episodes of cardiac asthma and pulmonary edema (the clinic of these conditions is described in the chapter "Acute circulatory failure");
• pulmonary edema almost always occurs as a two-way process, with auscultation of the lungs, crepitation and small bubbling rales are heard in the lower parts of both lungs;
• X-ray changes in the lungs with stagnant phenomena depend on the degree of expression of the stagnant process. At the stage of interstitial edema, the enhancement and deformation of the pulmonary pattern are revealed, thanks to the shadows of the longitudinal projections of the overcrowded small vessels. With the further progression of stagnant phenomena and the filling of the alveoli with the transudate, bilateral darkening (often of a rounded shape) appears without clear boundaries, mainly in the medial areas of the middle and lower fields. With a pronounced stagnation, the increase in the roots of the lungs is determined - they take the form of a butterfly;
• stagnation in the lungs develops, as a rule, against the background of other clinical manifestations of circulatory insufficiency (pronounced peripheral edema, ascites, enlarged painful liver);
• in the absence of concomitant pneumonia, congestion in the lungs is not accompanied by marked laboratory signs of inflammation;
• changes in the radiograph of a stagnant character are significantly reduced and may even completely disappear after successful treatment of heart failure;
• sometimes in the sputum of patients with congestion in the lungs, cells of the alveolar epithelium are found, the protoplasm of which contains in excess the phagocytosed grains of the hemoglobin derivative hemosiderin.

The above signs make it possible to distinguish pneumonia from stagnant phenomena in the lungs. However, one should take into account that pneumonia can develop against the background of stagnant phenomena in the lungs. In this case, an asymmetric obscuration is most radically detected in the lower lobe of the right lung, and laboratory signs of the inflammatory process appear.

Pneumonitis in systemic vasculitis and diffuse connective tissue diseases

With systemic vasculitis and diffuse connective tissue diseases, focal blackouts in the lower parts of the lungs or peribronchial, perivascular infiltration, enhancement of the pulmonary pattern can be observed. In differential diagnostics with pneumonia, attention should be paid to the characteristic clinical manifestations of systemic vasculitis and systemic diseases of connective tissue (systemic lesions, articular syndrome, as a rule, involvement of the kidneys in the pathological process, cutaneous erythematous, hemorrhagic rashes, etc.), appropriate laboratory manifestations, inefficiency antibacterial therapy and a positive effect of treatment with glucocorticosteroids.

Etiological diagnosis

At present, the problem of timely and successful aetiological diagnosis has become extremely relevant. An exact etiological diagnosis is the key to the correct and successful treatment of pneumonia.

The main methods of establishing the etiological diagnosis of pneumonia are:

• Careful analysis of clinical, radiological and laboratory features of pneumonia, depending on its etiology.
• Microbiological examination of sputum, sometimes bronchial flushing, pleural effusion with a quantitative assessment of the content of microflora. Sputum should be collected in sterile dishes after preliminary rinsing of the oral cavity. To increase the effectiveness of the study, it is expedient at first to perform sputum treatment using the Mulder method. To do this, take a purulent piece of sputum and thoroughly wash in a sterile isotonic solution of sodium chloride sequentially in three Petri dishes for 1 minute in each. This facilitates the removal from the surface of the lump of mucus of mucus containing the microflora of the upper respiratory tract and oral cavity. It is advisable to take at least three lumps from different parts of the sputum. After this, sputum is planted into elective biological media. A count is also made of the number of microbial bodies in 1 ml of sputum.

The pathogens of pneumonia in this patient are those microorganisms that are sown from sputum in an amount of 1,000,000 or more microbial bodies per ml.

Simultaneously with sowing sputum on elective biological media, sputum smears are performed with subsequent bacterioscopy. One smear is stained by the method of Romanovsky-Giemsa for cytological analysis (determine the type and number of leukocytes, the presence of bronchial, alveolar epithelium, erythrocytes, atypical cells and that). The second smear is stained by Gram and estimated abundance of microflora, the presence of Gram-positive and Gram-negative microorganisms, intracellular or extracellular localization. But first it should be established that the drugs belong to sputum, and not to the oral mucosa. The criteria for belonging to sputum preparations, stained according to Gram, are:

• the number of epithelial cells, the main source of which is the oropharynx, less than 10 per total counted cells;
• prevalence of neutrophilic leukocytes over epithelial cells;
• the predominance of microorganisms of a single morphological type. Bacterioscopy of sputum smears, stained by Gram, allows tentatively assume the causative agent of pneumonia. So, if gram-positive diplococci are found, one should think of pneumococcus; chains of gram-positive cocci are characteristic of streptococcus, bunch of Gram-positive cocci - for staphylococcus; short gram-negative rods - for a hemophilic rod; In addition, the gram-negative microorganisms include Moraxella, Neisseria, Klebsiella, Escherichia coli.

Immunological research. Immunological methods that allow verifying the causative agent of pneumonia include the detection of bacterial agents with the help of immune sera in the reaction of counter immunoelectrophoresis; determination of titers of specific antibodies (with the help of enzyme immunoassay, indirect hemagglutination reaction, complement fixation reaction). The role of the determination of specific antibodies in the blood serum increases especially when using the method of paired sera (a significant increase in the antibody titer in the re-examination after 10-14 days compared with the titers obtained at the onset of the disease).

[1], [2], [3], [4], [5], [6], [7], [8], [9]