Sputum examination: research goals and methods

Sputum is a secret secreted by inflammation of the trachea, bronchi and lungs. Its appearance is noted not only in the defeat of respiratory organs, but also in disorders of the heart and blood vessels. Methods of sputum examination imply a macroscopic, chemical and microscopic determination of its characteristics.

What does analysis reveal?

Sputum examination makes it possible to detect microorganisms causing a pathological process, to denote the presence of mycobacterium in tuberculosis, to identify cancer cells, blood and purulent impurities, and to determine the resistance of bacteria to antibiotics.

Under what conditions is the analysis

Sputum examination for general analysis is performed under the following conditions:

• cough;
• pneumonia;
• Inflammation of the bronchi;
• Suppuration of the lung;
• tuberculosis;
• Bronchiectatic disease;
• Pulmonary gangrene;
• Swelling in the lungs;
• Bronchitis in acute form;
• Bronchitis in chronic form;
• Tonsillitis in chronic form;
• tuberculosis;
• whooping cough;
• silicosis;
• Acute form of obstructive bronchitis;
• pneumonia;
• anthrax.

Preparation for research

Slime will be better to stand out if the day before the test is taken, take an expectorant or use a large amount of warm drink. Before collecting it is recommended to clean the teeth and mouth, rinsing it with warm boiled water.

Basic rules for collecting

It is desirable to collect sputum for bacteriological research in the morning (it accumulates the night before meals) in a sterile container that is issued by the laboratory. For the analysis, enough amounts of 5 ml. The secret is analyzed no later than 2 hours after its collection. Until the moment of shipment to the study, the container containing the contents should be kept closed in the refrigerator.

Sputum for various diseases

The amount of secreted secret varies depending on the nature of the pathological process. Usually it varies from several spittles to 1 liter per day. A small amount is allocated for inflammation of the bronchi, stagnant processes of the lungs and at the onset of an attack of bronchial asthma. At the end of the attack, the volume increases. It can be up to 0.5 liters, and also be released in large quantities if there is pulmonary edema.

A lot of mucus is secreted in the purulent process in the lungs when communicating with the bronchi, with suppuration, bronchiectasis and gangrene.

Sputum examination for tuberculosis shows the disintegration of lung tissue. In particular, this process provokes a cavern that communicates with the bronchi.

What is the reason for the decrease or increase in secretion

An increase in the amount of secreted secretion may be associated with a worsening of the patient's condition and observed during the period of exacerbation. The increase can relate to the positive dynamics of the disease.

Reducing the amount of mucus released may indicate regress of inflammation or a violation in the area of drainage of a cavity filled with pus. At the same time, the patient's state of health deteriorates.

The nature of the secretions

The mucous secretion is secreted in bronchitis in acute or chronic form, bronchial asthma, pneumonia, lung cancer, bronchiectasis, lung echinococcosis, accompanied by suppuration, actinomycosis.

Sputum with an admixture of pus is observed with lung abscess, echinococcosis and bronchoectatic disease.

A mucus with an admixture of blood or consisting entirely of blood is inherent in tuberculosis. The appearance of blood can indicate the presence of oncology, bronchoectatic disease, suppuration of the lung. Also, this phenomenon is observed in the syndrome of the middle lobe, heart attack in the lung, trauma, actinomycosis and syphilitic lesion. Blood can also be released during croupous and focal inflammation of the lungs, stagnant processes, cardiac asthma and pulmonary edema.

Serous sputum is noted with swelling of the lungs.

Sputum color

Examination of sputum reveals its different coloration. Mucous and serous discharge does not have color or have a whitish hue.

The addition of pus gives a greenish tinge to the secret, which characterizes such pathological processes as lung abscess, gangrene, bronchiectasis, actinomycosis of the lung.

Discharges with a touch of rust or brown indicate that they do not contain fresh blood, and the product of its decomposition is hematin. Such secret can be allocated for croupous pneumonia, anthrax, lung infarction.

Greenish color with an admixture of dirt or yellow secret indicates a pathology of the respiratory system in combination with jaundice.

In bright yellow, sputum is colored with eosinophilic pneumonia.

Ophthalmic slime occurs with lung siderosis.

Blackish or grayish secret is noted when there is an admixture of dust from the coal. When swelling of the lungs, serous sputum is observed in large numbers. As a rule, it is colored evenly in a pinkish color, which is due to the presence of red blood cells. Such secretions are similar to liquid cranberry mors.

It is possible to stain the secret from some medications. For example, the antibiotic "Rifampicin" can give it a red color.

Smell

The nature of the pathological process in the respiratory organs can be evidenced by the smell of secretion. Sputum gives off the smell of rot with gangrene of lung or putrefaction of bronchi, oncological neoplasms complicated by necrosis of bronchoectatic disease.

The presence of layers

Often the study of the secretions reveals the presence of layers. When the stagnant nature of sputum with an admixture of pus is observed with suppuration of the lung and bronchiectasis.

The secret with an admixture of rot contains three layers. The top layer is similar to foam, medium serous, and the bottom layer with an admixture of pus. Such a composition characterizes gangrene of the lung.

Impurities

An admixture of food can be noted in the presence of a malignant tumor in the esophagus when it is transmitted to the bronchi and trachea. When the echinococcus enters the bronchi in sputum, hooks or scolex of the parasite can be found. Very rarely, adult Ascaris are found, which penetrate the respiratory organs of weakened people.

Eggs of pulmonary fluky appear when the cyst ruptures, which is formed in the lungs in the presence of parasites.

Gangrene and suppuration of the lungs cause the appearance of pieces of lung necrosis. With a tumor in the secretions, fragments can be present.

Convolutions containing fibrin are found in patients with fibrinous bronchitis, tuberculosis and pneumonia.

Rice bodies, or Koch lenses, are inherent in tuberculosis.

Dietrich plugs, which include the decay products of bacteria and lung tissue cells of fatty acids, are found in putrefactive bronchitis or gangrene of the lung.

Chronic form of tonsillitis involves the excretion of the tonsils plugs, similar to the corks of Dietrich.

Chemical method

Sputum examination by chemical means involves the definition of:

• Protein index, which can help in the differential diagnosis of the chronic form of bronchitis and tuberculosis. With bronchitis of a chronic form, traces of protein are noted in the secret, and in the case of tuberculous lesions, the amount of protein in the sputum will be much higher, and it can be designated by numbers (up to 100-120 g / l).
• Bile pigments. They are found in sputum with a defeat of the respiratory system in combination with hepatitis. In this case, the liver communicates with the lungs. Bile pigments are inherent in pneumonia, which is due to the breakdown inside the lungs of erythrocytes and the subsequent change in hemoglobin.

Cytological method of studying the secret

For differential diagnosis of tuberculosis and many other lung lesions, the cytological method is widely used, which includes two stages: clinical and microscopic examination of sputum.

Clinical research helps determine which method should be used to collect the material in order to obtain the correct result of the analysis.

There are two main types of material that require sputum microscopy: spontaneous and reduced. The second type of secret is obtained by the action of various stimuli (means for expectoration, inhalation, etc.).

Material obtained with needle biopsy

Cytological examination of sputum suggests the study of macroscopic and microscopic analysis of its cells.

The most information for cytological analysis is sputum taken in the morning on an empty stomach. Before the study, it should be stored no more than 4 hours.

• Sputum cells of flat epithelium are found in the phlegm, which are examined microscopically. But for the diagnosis they do not matter. Cells of the cylindrical epithelium - both single and in the group - can be noted with such diseases as bronchial asthma, bronchitis and lung cancer. It should be noted that the cylindrical epithelium may also appear due to the penetration of mucus from the nasopharynx.
• Alveolar macrophages are cells of the reticuloendothelium. Macrophages that are contained in the protoplasm (phagocytic particles or dust cells) can be found in patients who have inhaled the dust for a long time.
• Macrophages of protoplasm (formed during the decay of hemoglobin) are called cells of cardiac defect. They can occur during stagnant processes in the lungs, stenosis of the mitral valve, pulmonary infarction.

• A small amount of white blood cells is contained in any sputum. Their increased content is noted in secret with an admixture of pus.
• Eosinophils. Such cells are rich in sputum in asthmatics. Cells can be noted with eosinophilic form of pneumonia, helminths, tuberculosis and lung infarction.
• Erythrocytes. Single red blood cells do not reflect the disease pattern. The appearance of an increased number indicates the presence of bleeding in the lungs. Unchanged erythrocytes are detected in fresh blood. If there is an admixture of blood that has stagnated in the lungs for a long time, then leached red blood cells are found.
• Cancer cells. They can be found in secret by groups. They indicate the presence of a tumor. When finding single cells, there is often a difficulty in diagnosing. In such cases, sputum analysis is repeated.
• Elastic fibers, the appearance of which is caused by the disintegration of lung tissue, triggered by tuberculosis, abscess, gangrene, tumor. Gangrene, such cells are not always characterized, because due to the action of enzymes that are in a secret, they can be dissolved.
• Kurshman's spiral. These are special bodies that look like tubes. They are found when examined under a microscope. Sometimes visible and with the eye. Typically, spirals are inherent in such diseases as bronchial asthma, pulmonary tuberculosis and pneumonia.
• Charcot-Leiden crystals are found in sputum with an increased content of eosinophils in such lesions as bronchial asthma, eosinophilic pneumonia. The opening of the focus of tuberculosis in the lumen of the bronchi may be characterized by the presence in the secret of elastic fiber crystals of cholesterol, MBT and amorphous lime (the so-called Ehrlich tetrad) - 100%.

Application of a bacterioscopy

The collection of sputum for the study by a bacterioscopic method implies the analysis of the secret for the detection of mycobacteria characteristic of tuberculosis. They are similar to thin, thickened on the sides or in the middle of curved sticks of different lengths, which are arranged either singly or in groups.

Detection of mycobacterium tuberculosis is not a dominant sign for diagnosis and requires confirmation by a bacteriological method. Tuberculous mycobacteria are not detected in secret.

The basis for the analysis is purulent particles, which are taken from forty-six different regions and are carefully triturated to a homogeneous mass with two glasses. Further they are dried in the air and fixed by the flame of the burner.

Bacteriological examination of sputum by the Tsilya-Nielsen method suggests its coloration in red. In this case, all the secret particles, with the exception of mycobacteria, acquire a blue tint, and the mycobacteria become red.

If there is a suspicion of a tuberculosis infection after a triplicate study for the presence of mycobacteria with a negative response, resort to a flotation technique (Pottenger analysis).

The usual way to study a stained smear on MTB gives a positive result only when the number of MTB is at least 50,000 units in 1 ml of sputum. According to the number of mycobacteria, it is impossible to judge the presence of tuberculosis.

Bacterioscopy of patients with nonspecific lung diseases

Laboratory tests of sputum in the presence of nonspecific lung diseases during bacterioscopy can identify the following bacteria:

• With pneumonia, pneumococci, Frenkel's diplococci, Friedlander bacteria, streptococci, staphylococci (100%).
• With gangrene of the lungs, a spindle-shaped stick can be found in combination with Vincent spirochete (80%).
• Yeast-like fungi (70%), to determine the type of which requires seeding secretions.
• Drusy actinomycete (100%) with actinomycosis.

The amount of secretion in a healthy person

The amount of mucus secreted by the trachea and bronchi in a person who does not suffer from any pathology ranges from 10 to 100 ml / day.

Normally, the level of leukocytes is low, and a study of a stained smear on mycobacteria gives a negative result.