Diagnostic capabilities of bronchoalveolar lavage
M.V. Samsonova
The introduction into clinical practice of fiber-optic bronchoscopy and the bronchoalveolar lavage (BAL) technique, which allows obtaining bronchial washings (BS) and bronchoalveolar washings (BAS), has significantly expanded the diagnostic capabilities in pulmonology. Thanks to the BAL technique, it has become possible to use a whole range of cytological, bacteriological, immunological, biochemical and biophysical methods. These studies contribute to the correct diagnosis of cancer and disseminated processes in the lungs, and also allow us to assess the activity of the inflammatory process in the bronchoalveolar space.
BAL technique
BAL is performed during fibrobronchoscopy under local or general anesthesia. The bronchoscope is inserted into the lobar bronchus (usually the middle lobe of the right lung), and the bronchial tree is washed with a large amount of saline heated to 37°C. After washing, the solution is completely aspirated from the bronchial tree.
The bronchoscope is inserted into the mouth of the segmental bronchus, occluding it. A polyethylene catheter is passed through the biopsy channel of the bronchoscope and 50 ml of saline is injected into the lumen of the segmental bronchus, which is then completely aspirated. The resulting portion of liquid is a bronchial wash. Then the catheter is advanced 6-7 cm deep into the segment
Maria Viktorovna Samsonova -
doc. honey. sciences, head lab. Pathological Anatomy Research Institute of Pulmonology of Roszdrav.
bronchus and 4 portions of 50 ml of physiological solution are injected in fractions, which are completely aspirated each time. These mixed portions constitute the bronchoalveolar lavage.
Methods for studying BS and ALS
The main methods for studying BS and ALS include biochemical and immunological studies of the supernatant, as well as the study of cell sediment. At the same time, the viability of BS and ALS cells, a cytogram are calculated, cytochemical studies of the cells are carried out, as well as a cytobacterioscopic assessment. Recently, a method for calculating the macrophage formula of ALS has been developed for various diseases of the bronchopulmonary system. The BAL study also allows you to assess the state of the surfactant system of the lungs by measuring surface tension and studying the phospholipid composition of the surfactant.
A bronchial portion of BAL fluid is used to conduct qualitative and quantitative microbiological studies. In addition, changes in the cellular composition of the BS can determine the severity of the inflammatory reaction in the bronchial tree.
bronchial epithelium 5-20%
including
columnar epithelium 4-15% squamous epithelium 1-5%
alveolar macrophages 64-88% neutrophils 5-11%
lymphocytes 2-4%
mast cells 0-0.5%
eosinophils 0-0.5%
A normal cytogram of the alveolar portion of BAL (Fig. 1) is shown in Table. 1.
Diagnostic value of studying BS and ALS
The study of BS and ALS has the greatest diagnostic significance for assessing the degree of inflammation in the tracheobronchial tree, in lung tumors and alveolar proteinosis.
Cytological examination of ALS has a high diagnostic value only for some lung diseases. Such nosologies include histiocytosis X, in which Langer-Hans cells appear (in their cytoplasm, upon electron microscopy, characteristic X-bodies are determined; according to the immunophenotype, these are CD1+ cells). Using BAS it is possible to confirm the presence of pulmonary hemorrhage. The study of ALS is also indicated in the verification of alveolar proteinosis, which is characterized by the presence of extracellular substance (Fig. 2), well determined using light (PIR reaction) and electron microscopy. In this disease, BAL serves not only as a diagnostic, but also as a therapeutic procedure.
Rice. 1. Normal cellular composition of ALS. Staining according to Romanovsky. x400.
In case of pneumoconiosis, using a BAS study it is only possible to confirm exposure to the dust agent. Specific diagnosis of beryllium disease can be carried out by studying the functional proliferative activity of ALS cells in response to the action of beryllium salts. With asbestosis in the BAS, asbestos bodies can be detected (Fig. 3) in the form of characteristic fibers - both extracellularly and intracellularly. These bodies are asbestos fibers with hemosiderin, ferritin, and glycoprotein aggregated on them, so they stain well when performing the PAS reaction and Perls staining. It is extremely rare that asbestos bodies are found in persons who have had non-occupational contact with asbestos, and the concentration of such particles in BAS does not exceed 0.5 in 1 ml. Pseudoasbestos bodies can also be found in ALS - in pneumoconiosis associated with exposure to dust from coal, aluminum, glass fibers, etc.
In patients with immunodeficiency conditions (in particular, HIV infection), BAL is the method of choice for detecting pathogens of infectious lung lesions. The sensitivity of BAL fluid in diagnosing Pneumocystis infection (Fig. 4), according to some data, exceeds 95%.
In other diseases, the study of BAS is not highly specific, but can provide additional information, which is assessed in conjunction with clinical, radiological, functional and laboratory data.
With diffuse alveolar hemorrhage (DAH), which occurs in various diseases, free and phagocytosed erythrocytes and siderophages can be found in the ALS (Fig. 5). BAS is an effective method for detecting BAV even in the absence of hemoptysis, when the diagnosis of this condition is extremely difficult. BAV should be differentiated from acute respiratory distress syndrome (ARDS),
in which siderophages also appear in the BAS.
As part of the differential diagnosis of idiopathic fibrosing alveolitis (IFA), cytological examination of ALS allows one to exclude other interstitial lung diseases. Thus, a moderate increase in the proportion of neutrophils and eosinophils in ALS does not contradict the diagnosis of ELISA. A significant increase in the percentage of lymphocytes and eosinophils is not typical for ELISA, and in these cases one should think about other alveolitis (exogenous allergic, medicinal or occupational).
Cytological examination of ALS serves as a sensitive method in the diagnosis of exogenous allergic alveolitis (EAA). A high percentage of lymphocytes, the presence of plasma and mast cells, as well as “dust” macrophages, in combination with anamnestic and laboratory data, makes it possible to diagnose EAA. Possible appearance of eosi-
Table 1. Normal ALS cytogram
Cellular composition of ALS Non-smokers Smokers
Cytosis, number of cells x106/ml 0.1-0.3 >0.3
Alveolar macrophages, % 82-98 94
Lymphocytes, % 7-12 5
Neutrophils,% 1-2 0.8
Eosinophils, %<1 0,6
Mast cells, %<1 <1
Rice. 2. Extracellular substance in ALS with alveolar proteinosis. Staining according to Romanovsky. x400.
nofils or giant multinucleated cells (Fig. 6). Among lymphocytes, cells with the immunophenotype C03+/C08+/C057+/C016- predominate. It should be remembered that several months after the onset of the disease, along with T-suppressors, the number of T-helpers begins to increase. Additional research methods make it possible to exclude other diseases in which there is an increase in the proportion of lymphocytes in the ALS - diffuse connective tissue diseases, drug-induced alveolitis (LA), obliterating bronchiolitis with organizing pneumonia (OBOP), silicosis.
In sarcoidosis, there is also an increase in the proportion of lymphocytes in the BAS, and sarcoidosis is characterized by co-
Rice. 4. Pneumocystis jiroveci in ALS. Staining according to Romanovsky. x400.
Rice. 5. Siderophages in ALS. Perls staining. x100.
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Rice. 6. EAA: increased proportion of eosinophils, neutrophils, lymphocytes in BAS, multinucleated giant cell. Staining according to Romanovsky. x200.
Rice. 7. “Amiodarone lung” (LA): macrophages with foamy cytoplasm in ALS. Staining according to Romanovsky. x1000, oil immersion.
Rice. 8. Lymphocytic type of ALS cytogram. Staining according to Romanovsky. x1000, oil immersion.
the ratio of T-helpers and T-suppressors (CO4+/CD8+) is above 3.5 (the sensitivity of this sign is 55-95%, specificity is up to 88%). Multinucleated giant cells (a type of foreign body cell) may also be found in the ALS of patients with sarcoidosis.
Rice. 9. Neutrophilic type of ALS cytogram. Staining according to Romanovsky. x1000, oil immersion.
With medicinal alveoli-
Thus, morphological changes in the lungs can be varied; alveolar hemorrhagic syndrome or ABOP is often observed. In the cytogram of ALS, an increase in the proportion of eosinophils and neutrophils may be noted, but most often with LA opi-
Table 2. Examples of the use of cytological analysis of ALS for differential diagnosis (according to OgeP M. et al., 2000)
Cytogram indicators
ALS and their assessment
Clinical examples of ALS cytogram
Cytosis, x104/ml 29 110 100 20 64
Macrophages, % 65.8 18.2 19.6 65.7 41.0
Lymphocytes, % 33.2 61.6 51.0 14.8 12.2
Neutrophils, % 0.6 12.8 22.2 12.4 4.2
Eosinophils, % 0.2 6.2 7.0 6.8 42.2
Mast cells, % 0.2 1.0 0.2 0.3 0.4
Plasmocytes, % 0 0.2 0 0 0
CO4+/CO8+ ratio 3.6 1.8 1.9 2.8 0.8
Bacterial culture - - - - -
The most likely diagnosis is Sarcoidosis EAA LA ELISA OEP
Probability of correct diagnosis*, % 99.9 99.6 98.1 94.3 Not calculated
*Calculated using a mathematical model. Designations: AEP - acute eosinophilic pneumonia.
indicate an increase in the percentage of lymphocytes, among which, as a rule, CD8+ cells predominate. A very high content of neutrophils in BAS occurs when taking the antidepressant nomifensine (the proportion of neutrophils can reach 80%, followed by a decrease and a simultaneous increase in the number of lymphocytes). With amiodarone LA (“amiodarone lung”), specific changes in ALS occur in the form of the appearance of a large number of “foamy” macrophages (Fig. 7). This is a very sensitive, but low-specific sign: the same macrophages can be found in other diseases (EAA, OBOP), as well as in patients taking amiodarone in the absence of alveolitis (amiodarone increases the content of phospholipids, especially in phagocytes).
In other cases, when BAL does not reveal highly specific signs of any disease, this method makes it possible to limit the differential diagnostic search (Tables 2 and 3) to a certain group of nosological units with one or another type of alveolitis:
Lymphocytic (increased proportion of lymphocytes, Fig. 8): sarcoidosis, hypersensitivity pneumonitis, post-radiation pneumonia, ELISA, chronic infectious process in the lungs, AIDS, silicosis, Sjogren's syndrome, Crohn's disease, carcinomatosis, drug-induced pneumopathy;
Neutrophilic (increased proportion of neutrophils, Fig. 9): scleroderma, dermatomyositis, acute infectious process in the lungs, sarcoidosis in a malignant course, asbestosis, drug-induced alveolitis;
Eosinophilic (increased proportion of eosinophils, Fig. 10): Cher-ja-Strauss angiitis, eosinophilic pneumonia, drug-induced alveolitis;
Mixed (Fig. 11): tuberculosis. histiocytosis.
When diagnosing lung cancer, the BAL method has an advantage
Table 3. Cytological indicators of ALS are normal and their changes in various pathologies (according to OgeP M. et al., 2000)
Alveolar macrophages Lymphocytes Neutrophils Eosinophils Plasmocytes Mast cells CD4+/CD8+ ratio
Normal values
Non-smokers 9.5-10.5* 0.7-1.5* 0.05-0.25* 0.02-0.08* 0* 0.01-0.02* 2.2-2.8
85-95% 7,5-12,5% 1,0-2,0% 0,2-0,5% 0% 0,02-0,09%
Smokers 25-42* 0.8-1.8* 0.25-0.95* 0.10-0.35* 0* 0.10-0.35* 0.7-1.8
90-95% 3,5-7,5% 1,0-2,5% 0,3-0,8% 0% 0,02-1,0%
Non-infectious diseases
Sarcoidosis T = =/T - =/T T/=/4
EAA “Foamy” MF TT T =/T +/- TT 4/=
Medicinal “Foamy” MF TT T T +/- TT 4/=
alveolitis
ELISA T T/TT T - T =
OBOP “Foamy” MF T T T -/+ =/T 4
Eosinophilic T = TT +/- =/T 4
pneumonia
Alveolar “Foamy” MF T = = - N.d. T/=
proteinosis
Diseases of the joint - T =/T =/T - =/T T/=/4
body fabric
Pneumoconiosis VKV (particles) T T =/T - =/T T/=/4
Diffuse alveo- Color =/T T =/T - N.d. =
lary bleeding on Fe: +++
ARDS Coloring for Fe: + T TT T - =/T 4/=
Malignant tumors
Adenocarcinoma = = = - = =
Cancerous lymphangitis T T/= T/= -/+ T/= 4/=
Hemoblastosis T T T -/+ T 4/=
And infections
Bacterial BCV (bacteria) = TT T - N.d. =
Viral VKV T T T - N.d. T/=
Tuberculosis BCV (mycobacteria) T = T - T =
HIV VKV T T T/= - N.d. 4
Designations: MF - macrophages, VKV - intracellular inclusions; indicator: T - increased; TT - significantly increased; 4 - reduced; =/T - not changed, less often increased; T/=/4 - can be increased, decreased or not changed; T/TT - increased, less often significantly increased; T/= - increased, less often unchanged; 4/= - decreased, less often not changed; = - not changed; - No; -/+ - rare; +/- occur; N.d. - no data.
* Data are presented in absolute numbers x104ml-1.
before examining sputum to detect tumor cells, since the material may be
obtained from the lobe or segment where the tumor is localized. BAL makes it more likely
diagnose peripheral tumors, including bronchioloalveolar cancer (Fig. 12).
Rice. 10. Eosinophilic type of ALS cytogram, Char-co-Leiden crystals. Staining according to Romanovsky. x200.
Rice. 11. Mixed type of ALS cytogram: increased proportion of lymphocytes, neutrophils, eosinophils. Staining according to Romanovsky. x1000, oil immersion.
Rice. 13. ALS in chronic bronchitis: the presence of cylindrical ciliated cells, neutrophils, accumulation of coccal flora. Staining according to Romanovsky. x1000, oil immersion.
Rice. 14. Mycobacterium tuberculosis in ALS. Ziehl-Neelsen staining. x1000, oil immersion.
Rice. 15. Pseudomycelium of the fungus Candida albicans in ALS. Staining according to Romanovsky. x200.
The cytobacterioscopic method makes it possible to identify and semi-quantitatively assess the content of bacteria (Fig. 13), mycobacteria (Fig. 14) and fungi (Fig. 15) in BAS. These results (bacteria can be differentiated by Gram) serve as the basis for prescribing appropriate antibacterial therapy until the results of bacteriological examination are obtained. In casuistic
Rice. 16. Significant increase in the number of neutrophils in ALS, numerous protozoa such as amoebas. Staining according to Romanovsky. x200.
The study of BAS allows one to assess the degree of activity of the inflammatory process in infectious diseases and the effectiveness of the therapy. A low degree of inflammatory activity is characterized by an increase in the proportion of neutrophils in BAS within 10%,
medium - up to 11-30%, high - more than 30%.
The use of histochemical methods for studying BAL cells is possible with their high viability (more than 80%).
Conclusion
When assessing changes identified in BS and BAS, you should adhere to certain rules and remember the following:
The identified changes are characteristic only of the segment under study, so they should be treated with caution if the process is not diffuse in nature;
The identified changes are typical for a given point in time;
Since the lungs are simultaneously exposed to many factors (smoking, pollutants, etc.), it is always necessary to exclude the possibility of the influence of these factors on the development of pulmonary pathology.
Chernyaev A.L., Samsonova M.V. Pathological anatomy of the lungs: Atlas / Ed. Chuchalina A.G. M., 2004.
Shapiro N.A. Cytological diagnosis of lung diseases: Color atlas. T. 2. M., 2005.
Baughman R.P Bronchoalveolar Lavage. St. Louis, 1992.
Costabel U. Atlas of Bronchoalveolar Lavage. L., 1998.
Drent M. et al. //Eur. Resp. Monograph. V 5. Mon. 14. Huddersfield, 2000. P. 63.
Books from the Publishing House “ATMOSPHE”
Amelina E.L. etc. Mucoactive therapy /
Ed. A.G. Chuchalina, A.S. Belevsky
The monograph summarizes modern ideas about the structure and functioning of mucociliary clearance, its disorders in various respiratory diseases, research methods; The main medicinal and non-medicinal methods for correcting mucociliary clearance in bronchopulmonary pathology are considered. 128 p., ill.
For general practitioners, therapists, pulmonologists, medical students.
Microbiological and immunological studies of BS and ALS should be carried out to the same extent as sputum examination, and for similar indications. BS and ALS acquire the greatest diagnostic significance when assessing the level of inflammation in the tracheobronchial tree, with lung tumors and pulmonary proteinosis. Currently, a biochemical and immunological study of the supernatant of BS and BAS, as well as a study of the cell sediment, is being carried out. At the same time, the viability of BS and BAL cells, a cytogram are calculated, cytochemical studies of BAL cells are carried out, as well as a cytobacterioscopic assessment. Recently, a method has been developed for calculating the macrophage formula of BAL fluid for various diseases of the bronchopulmonary system. The study of BAL allows, by measuring surface tension and studying the phospholipid composition of the surfactant, to assess the state of the surfactant system of the lungs.
Bronchial portion of bronchoalveolar lavage used for qualitative and quantitative microbiological studies. In addition, changes in the cellular composition of the BS can determine the severity of the inflammatory reaction in the bronchial tree. According to the recommendations of the European Society of Pulmonology, the following composition of BS is typical for the norm:
It has high diagnostic value only for some lung diseases. Interstitial diseases in which the study of the cellular composition of ALS may be useful include histiocytosis X, in which Langerhans cells appear with characteristic X bodies in the cytoplasm, determined by electron microscopic examination (according to the immunophenotype, these are CD1+ cells). Using BAS it is possible to confirm the presence of pulmonary hemorrhage. The study of ALS is indicated in the diagnosis of alveolar proteinosis, which is characterized by the presence of an extracellular substance that is well determined using light (PIR reaction) and electron microscopy. In this disease, BAL is not only a diagnostic, but also a therapeutic procedure.
For interstitial lung diseases caused by inhalation of dust particles, using BAS testing it is only possible to confirm exposure to the dust agent. Specific diagnosis of beryllium disease can be carried out by studying the functional proliferative activity of ALS cells in response to the action of beryllium salts. With asbestosis, silicate bodies can be found in the BAS in the form of characteristic fibers - the so-called “glandular” bodies. Such asbestos bodies are asbestos fibers with hemosiderin, ferritin, and glycoprotein aggregated on them. Therefore, they stain well when performing the CHIC reaction and Perls staining. The described fibers in the wash can be detected both extra- and intracellularly. It is extremely rare that asbestos bodies can be found in persons who have had non-occupational contact with asbestos, and the concentration of such particles in the BAS will not exceed 0.5 ml. Pseudoasbestos bodies, described for pneumoconiosis associated with exposure to coal, aluminum, glass fibers, etc., can also be found in ALS.
Bronchoalveolar lavage is the method of choice when it is necessary to obtain material from the lower parts of the lungs in patients with immunosuppressive conditions. At the same time, the effectiveness of the study for detecting infectious agents has been proven. Thus, the sensitivity of BAL fluid in diagnosing Pneumocystis infection, according to some data, exceeds 95%.
For other diseases, ALS testing is not highly specific, but can provide additional information in a complex of clinical, radiological, functional and laboratory data. Thus, with diffuse alveolar bleeding, free and phagocytosed erythrocytes and siderophages can be detected in the BAS. This condition can occur in various diseases; BAS is an effective method for detecting diffuse bleeding even in the absence of hemoptysis, when the diagnosis of this condition is extremely difficult. It should be remembered that diffuse alveolar hemorrhage should be differentiated from diffuse alveolar damage - adult respiratory distress syndrome, in which siderophages also appear in the lavage.
One of the most serious differential diagnostic problems- diagnosis of idiopathic fibrosing alveolitis. When solving this problem, cytological examination of BAL allows one to exclude other interstitial lung diseases. Thus, an increase in the proportion of neutrophils and eosinophils in ALS does not contradict the diagnosis of idiopathic alveolitis. A significant increase in the number of lymphocytes is not typical for this disease; in these cases, one should think about exogenous allergic alveolitis or other medicinal or occupational alveolitis.
Cytological examination of ALS is a sensitive method in the diagnosis of exogenous allergic alveolitis. A high percentage of lymphocytes, the presence of plasma and mast cells, as well as foamy macrophages, in combination with anamnestic and laboratory data, allow us to diagnose this nosology. It is possible that eosinophils or giant multinucleated cells may appear in the ALS. Among lymphocytes, cells with the immunophenotype CD3+/CD8+/CD57+/CD16- predominate. It should, however, be remembered that in the late phase of the disease, several months after the onset of the disease, along with suppressors, the number of T-helper cells begins to increase. Other research methods make it possible to exclude other diseases in which there is an increase in lymphocytes - collagen diseases, drug-induced pneumonitis, bronchiolitis obliterans with organizing pneumonia or silicosis.
For sarcoidosis an increase in the proportion of lymphocytes was also noted, however, it was shown that the ratio of helpers and suppressors (CD4+/CD8+) above 4 is characteristic of this particular nosological form (the sensitivity of this sign is, according to various authors, from 55 to 95%, specificity - up to 88% ). In the ALS of patients with sarcoidosis, giant multinucleated cells of the “foreign body” type may also be found.
For medicinal alveolitis morphological changes in the lungs can be varied; alveolar hemorrhagic syndrome or bronchiolitis obliterans with organizing pneumonia are often observed. In the cellular composition of ALS, an increase in eosinophils, neutrophils, and lymphocytes is noted, and sometimes a combined increase in these cells is possible. However, most often with drug-induced alveolitis, an increase in lymphocytes is described, among which suppressor cytotoxic cells (CD8+) usually predominate. An extremely high content of neutrophils occurs, as a rule, when taking the antidepressant nomifensine, especially in the first 24 hours. In this case, the proportion of neutrophils in BAS can reach 80%, followed by a decrease within 2 days to 2%, at the same time the proportion of lymphocytes in the washout increases . Similar observations have been described for exogenous allergic alveolitis. When taking amiodarone and developing drug-induced alveolitis (the so-called “amiodarone lung”), specific changes in BAS occur, characterized by the appearance of a large number of foamy macrophages. This is a very sensitive, but not very specific sign: the same macrophages can be found in other diseases, including exogenous allergic alveolitis and bronchiolitis obliterans with organizing pneumonia. The same macrophages can be found in individuals taking amiodarone, but without the development of alveolitis. This is due to the fact that this substance increases the content of phospholipids, especially in phagocytes.
is a bronchoscopic method of obtaining a wash from the surface of the smallest bronchi (bronchioles) and alveolar structures of the lungs for cytological, microbiological, biochemical and immunological studies. Sometimes used for medicinal purposes to cleanse inflamed airways from excess secretory purulent contents.
In veterinary practice, we use this diagnostic method to conduct a cytological analysis of the obtained material, as well as for bacteriological examination. Thus, the diagnosis includes a qualitative/quantitative assessment of the cells that make up the bronchial mucus (for example, eosinophilic or neutrophilic inflammation predominates in the patient). Also, the resulting material is sown on nutrient media in order to determine which pathogen colonizes the surface of the bronchi and the sensitivity of the found microorganism to antibiotics is titrated.
When exactly is the study carried out?
Very often, animals with a history of chronic coughing attacks (the onset of symptoms was noted more than 1 month ago), periodically occurring noisy breathing, attacks of suffocation, and so on are brought to see a veterinarian.
Interestingly, neither a chest x-ray nor a complete blood count or nasal swabs can help differentiate feline asthma from bronchitis. Changes on a chest x-ray are nonspecific: as a rule, they are the same type of enhancement of the bronchial or broncho-interstitial pattern. As for washings from the surface of the upper respiratory tract, it should be remembered that the microbial landscape at the level of bronchioles and mucous membranes of the nasal passages is very different, and when mycoplasma is detected on the surface of the conjunctiva of the eye, we have no right to say that this pathogen causes irreversible changes at the level of the bronchi.
In dogs, chronic cough can also be diagnosed using a BAL. Thus, dog cough can be a symptom of very different diseases. For example, infectious and idiopathic bronchitis show the same changes on chest x-ray, but require completely different treatment. A very valuable method for selecting therapy for the development of severe pneumonia that is refractory to antibiotic treatment in puppies and young dogs. After all, bacteriological research allows you to accurately determine which pathogen is resistant to the standard antibacterial regimen. It is also possible to accurately and quickly select the necessary and specific antibiotic.
In addition, using the method, we can exclude eosinophilic pulmonary infiltration syndrome, which develops in young animals and requires aggressive steroid therapy to stop attacks, while steroids prescribed for an active bacterial process can kill the patient.
How exactly is the research carried out?
To collect swabs from the surface of the bronchi, we use the bronchoscopy method. A bronchoscope is inserted approximately to the level of the 2-3rd order bronchi, which makes it possible to examine the surface of the bronchial tree, as well as to exclude possible foreign objects that have entered the respiratory tract, for example, during active running. Next, using a bronchoscope, we inject a small volume of sterile solution and very quickly take it back. The resulting material is examined under a microscope and plated on special media.
Method safety
Bronchoalveolar lavage is considered safe, very effective in making a diagnosis, and often has a therapeutic effect. Characteristically, the cough disappears for a short time after the procedure. Requires minimal anesthesia (sedation). When carrying out specific preparation, it has no side effects.
Why do this research?
It is very important to understand that a chronic, prolonged, progressive cough often indicates the development of irreversible, severe bronchopulmonary problems, which, even with well-chosen therapy, may not respond well to treatment. Feline asthma has a high risk of sudden death. So, a timely diagnosis and selected therapy can get rid of problems at an early stage and significantly improve the quality of life of your pet.
Veterinarian
Filimonova D.M.
Today, fiberoptic bronchoscopy is a common standard diagnostic procedure that allows direct examination of the upper and lower airways. As the endoscope moves through the nasopharynx and trachea, large bronchi can easily determine the amount of mucus, as well as the degree of swelling of the mucous membrane and bronchospasm. In addition to examining the lumen of the airways, one of the great advantages of bronchoscopy is the ability to take samples from large and small airways and alveoli. The resulting samples are then analyzed for their cellular and non-cellular constituents.
In recent years, in cases of suspected diffuse inflammatory disease, bronchoalveolar lavage (BAL) using an endoscope or special tube has become somewhat more popular than more traditional methods of obtaining samples such as tracheal aspiration. For many years, it was believed that obtaining samples from the lower trachea provides representative information about the condition of the alveoli and small airways, since free airway cells from the peripheral lung are eventually flushed toward the trachea for removal.
However, a large case study of young performance horses with low performance associated with lower respiratory tract pathology found that cytologic and bacteriologic findings were poorly correlated between specimens obtained by tracheal aspiration and those obtained by BAL. Studies have shown that the numbers of different cells in cytological preparations from tracheal aspirates and BAL from the same horse varied significantly. This suggests that samples from tracheal fluid collections may not accurately reflect the population of cells and secretions present within the small airways and alveoli. This is important because exercise intolerance, inflammatory airway damage, and hyperresponsiveness are associated with small airway disease, and the best diagnostic method is BAL cytology. In addition, bacterial culture of tracheal aspirates yielded more positive results than culture of BAL performed on the same case. Thus, the lower part of the trachea apparently contains normal bacterial flora, which may be absent in the small airways and alveoli. For these reasons, BAL has become an increasingly popular tool for assessing inflammation of the distal (small) airways compared with obtaining samples by tracheal aspiration.
To substantiate the value of differential cell abundance in BAL fluid as an additional diagnostic tool for the evaluation of the respiratory system, other quantitative measurements are needed in addition to routine clinical examination. Emphysema syndrome has been studied in detail over the past two decades, and several research laboratories around the world have clearly demonstrated a high correlation between BAL cell differentiation and pulmonary function and histamine bronchochallenge testing in emphysema horses. In recent years, similarly characterized lung function in young performance horses with non-infectious inflammatory airway disease (IAD) has been consistent with these findings regarding the diagnostic utility of bronchoalveolar lavage.
The purpose of this chapter is to discuss the use of bronchoalveolar lavage technique as a tool to identify and characterize inflammation in the lungs of horses that suffer from diffuse pulmonary pathology, such as IAD in young performance horses and emphysema syndrome in adult animals. In addition, viral and bacterial lung diseases are briefly reviewed in terms of their diagnosis using bronchoalveolar lavage.
INDICATIONS FOR BRONCHOALVEOLAR LAVAGE
Inflammation of the lower respiratory tract in horses can develop for various reasons. Horses of any age can suffer from infectious (bacterial/viral) and non-infectious IAD and may exhibit a variety of clinical, physiological and pathological signs. In a large prospective study of 2- to 3-year-old Thoroughbred horses in training, coughing and nasal discharge were second only to lameness as the most common reason for missed training days. Non-infectious IAD is the most common respiratory pathology occurring in both young and adult performance horses.
The dominant feature of IAD is airway obstruction resulting from accumulation of secretions, thickening of the airway walls, transformation of the airways and, ultimately, in advanced cases, loss of the ability to maintain the diameter of the lumen of the small airways. Airway hyperresponsiveness is a consequence of the inflammatory process and leads to further obstruction due to bronchospasm and other functional abnormalities. In healthy horses, bronchospasm occurs in response to inhalation of a histamine aerosol at a concentration of 16 mg/ml. In contrast, in older horses with emphysema, bronchoconstriction occurs from inhaled histamine concentrations of less than 8 mg/ml. In performance horses 2 to 5 years of age with IAD, bronchoconstriction occurs in response to inhaled histamine at concentrations as low as 2 to 3 mg/mL, indicating even greater airway hyperresponsiveness. This severe airway hyperresponsiveness correlates with increased levels of inflammatory cells in BAL samples, and BAL is therefore an extremely useful tool for investigating the nature and basis of inflammatory airway disease.
The prevalence of poor performance due to respiratory problems is significant, especially in racehorses. Common respiratory abnormalities in this animal population include IAD, exercise-induced pulmonary hemorrhage, and upper airway dysfunction. In this context, IAD makes a significant contribution to substandard athletic performance, interrupted racing or training, and ultimately the premature end of a sporting career. Histological examination of lung specimens from older horses (>10 years) revealed a significant prevalence of non-infectious IAD in this age group. Therefore, IAD plays a significant role in the health and performance of horses of all age groups and sporting disciplines. Bronchoscopy and bronchoalveolar lavage to determine the nature and extent of such inflammation are extremely important to determine appropriate treatment and prognosis in each case.
Less common pathologies, but also significant for performance horses of all ages, are septic lung diseases such as lung abscesses and parapneumonic effusions. Abscesses are usually localized in the cranial part of the right or left caudal lobe of the lung." These diseases can be easily recognized clinically due to the presence of increased body temperature, anorexia and pain on palpation of the chest. Suspicion of bronchopneumonia or lung abscess is confirmed by radiography. However, in such patients, -Bronchoscopy still has value for both diagnostic and therapeutic purposes. During bronchoscopy, reddish-brown mucous secretion in the lower trachea is easily detected. Carefully moving the endoscope further around this collection, being careful not to touch these secretions, is often possible. follow the strip of discolored mucopurulent secretion and identify the specific segmental bronchial source. Then, using the biopsy channel of the bronchoscope, a polyethylene catheter can be inserted into the specific bronchus in order to obtain a sterile sample of secretions for bacterial culture and cytological analysis. Once this procedure is completed, a small volume of fluid (approximately 200-250 ml in 2 or 3 injections) can be infused into the affected bronchus and immediately aspirated to remove excess exudate. This process is called "toilet" of the airways, not bronchoalveolar lavage. This procedure provides therapeutic benefits by reducing bacterial attack and reducing exudative overload in the affected region of the lung. After the final suction of the fluid and before removing the endoscope, a dose of dissolved antibiotic can be locally injected into the affected area. This procedure may be repeated daily or every other day as a component of treatment for bacterial bronchopneumonia in combination with systemic therapy.
BRONCHOALVEOLAR LAVAGE PROCEDURE
BAL can be performed in most horses under mild sedation (xylazine 0.3-0.5 mg/kg IV or romifidine 0.03-0.05 mg/kg IV) and airway anesthesia with local anesthetic (0.4% lidocaine without epinephrine). This procedure can be performed using a 1.8-2 m bronchoscope or a special BAL tube (Bivona Medical Technologies, Gary, Ind.). When the bronchoscope or BAL tube is in contact with the trachea, reaching the tracheal bifurcation usually provokes coughing. Therefore, at this stage it is useful to infuse 60-100 ml of pre-warmed lidocaine solution (0.4% without epinephrine) to desensitize the cough receptors located in the bifurcation. After this infusion, the endoscope or BAL tube is carefully, without excessive force (this is determined by the degree of resistance to further advancement ) is introduced deeper. Pre-warmed saline (200-300 ml) is quickly infused into the lung and then aspirated.
The total volume of saline solution for infusion should be divided into two separate boluses, while trying to get as much fluid as possible between each bolus. In general, a return of 40-60% of the total infusate volume indicates a satisfactory BAL. In horses with advanced disease, small volumes are collected and there is a lesser tendency for less foam (surfactant) to be present. BAL fluid samples are then pooled and kept on ice if processing is not possible within 1 hour of receipt. The fluid should be assessed macroscopically to identify any flocculent debris or discoloration. One or two serum or EDTA tubes are filled with VAL fluid and centrifuged (1500 rpm for 10 minutes); After removing the supernatant, smears are prepared from a drop of sediment, which are then air-dried. When preparing smears, slides must be air dried quickly using a small tabletop fan to well preserve cell morphology. Smears prepared in this way can be stored at room temperature for up to 8-10 months with minor cellular changes. Air-dried smears can be stained with Diff-Qnik, Wright-Giemsa, May Grmnwald, Leishman, or Gram stains for interpretation of cellular and noncellular components. Cellular profile and morphology may provide clues to the nature of airway injury, inflammation, and the lung's immunological response to infection or foreign antigens.
DIFFERENTIAL COUNTING OF CELLS IN BAL AND THEIR INTERPRETATION
In the field, the volume of fluid administered often varies, ranging from 60 to 300 ml of sterile saline per VAL. Additionally, in horses with severe bronchospasm, the volume of fluid withdrawn may be significantly reduced. Due to these circumstances, the dilution effect makes it difficult to accurately count the total number of nucleated cells, and given the wide range of TaKoii values, the count is of little clinical value in the interpretation of inflammatory conditions of the lungs and is considered to have no diagnostic value.
On the other hand, differential abundance of cell types is largely unaffected by dilution and is valuable for characterizing pathological increases in specific cell populations. Thus, with the help of differential cell counting, it is possible to identify the characteristic features of septic, non-septic and viral inflammatory diseases of the respiratory tract, which helps in deciding on the therapeutic approach in each specific case. Ranges of values were established for differential BAL cell abundance in healthy horses, horses with emphysema, and performance horses with poor performance. In each of the corresponding groups, characteristic cytological features are present.
Differential cell counting in healthy horses
Ranges of differential BAL cell counts were established by obtaining BAL samples from horses not suffering from respiratory disease and were confirmed by various methods. including clinical examination, testing of pulmonary function and, in some cases, the absence of airway hyperresponsiveness in response to bronchoprovocation with histamine aerosol (Fig. 8.2-1). In young horses (6 years of age), the neutrophil population can average up to 15% of healthy animals (based on the diagnostic methods described above), with a corresponding decrease in the percentage of the macrophage and lymphocyte population.
Deviations in differential cell numbers
Emphysema syndrome is a commonly diagnosed respiratory disease in adult horses with a characteristic history, clinical signs, abnormal pulmonary function tests, and airway hyperresponsiveness. Horses with exacerbation of emphysema have at least 23% neutrophils in the BAL fluid (Figure 8.2-2). However, in such cases, neutrophils often account for more than a third of the differential abundance of all inflammatory cells and play a major role in the clinical syndrome and the aforementioned airway hyperresponsiveness. BAL cytology specimens from emphysema horses often have an abundant mucoid background with many nontoxic and apoptotic (senescent) neutrophils. trapped inside this slime. In the BAL fluid of horses suffering from emphysema, in addition to the increased number of neutrophils, there is also a significant increase in the total number of mast cells, eosinophils, lymphocytes, macrophages and epithelial cells. These cells must be recognized and assessed separately from neutrophils. The number of desquamated epithelial cells is usually increased as a result of damage to the lining of the mucosa due to severe inflammation. In horses suffering from emphysema, in addition to the glandular higher cellular components, non-cellular structures such as Kurschmann coils are often present in BAL preparations, which indicate chronic nonseptic inflammatory disease of the respiratory tract.
CONCLUSION
BAL is clearly emerging as a powerful adjuvant diagnostic tool to aid in the diagnosis of clinical and subclinical lower respiratory tract diseases, such as non-infectious inflammatory airway disease in young performance horses and recurrent airway obstruction, or emphysema, in older horses. The BAL cell differential for healthy horses has been well established using generally accepted standardized procedures, and any deviation of cytological profiles from normal values will help recognize a wide range of non-septic inflammatory processes. Although clinicians currently prescribe specific treatments based on BAL cell differential cytology, greater knowledge regarding various disorders may in the future allow equine clinicians to provide more accurate prognostic information regarding respiratory problems to trainers, athletes and owners. In addition, in most young and adult sport horses with copious amounts of white mucopurulent secretion in the respiratory tract and a markedly increased percentage of neutrophils in the cellular differential, a septic process cannot be detected. Rather, such cases demonstrate a nonseptic inflammatory disease of the airways.
Author(s): S.K. Sobakina, P.V. Belokopytov, A.N. Lapshin, S.G. Atanasova, A.A. Ivanova
Organization(s): Innovative Veterinary Center of the Moscow Veterinary Academy
Magazine:
№5 - 2018
UDC 619:616.24
Key words: bronchoalveolar lavage, bronchoalveoli, bronchoscopy. Key words: bronchoalveolar lavage, bronchoalveoli, bronchoscopy/
Abbreviations: BAL – bronchoalveolar lavage, surfactant – surfactant
Purpose of the study: to describe existing techniques for performing bronchoalveolar lavage
Abstract
Bronchoalveolar lavage (BAL) is a minimally invasive technique used in humane and veterinary medicine to collect samples from the lower order bronchi and alveolar spaces.
BAL sampling is used to study the innate, cellular, and humoral cellular responses due to the presence of a population of cells that may facilitate the diagnosis of various diffuse lung diseases.
Bronchoalveolar lavage (BAL) is a minimally invasive technique used in human and veterinary medicine to sample the lower generation bronchi and alveolar spaces.
BAL sampling is used to study the congenital, cellular and humoral cellular response due to the presence of a cell population caused by the presence of a population of cells that can facilitate the diagnosis of various diffuse pulmonary diseases.
Bronchoscopy and BAL can provide definitive diagnoses in cases of inflammatory airway disease, bronchiectasis, eosinophilic pneumonia, pulmonary parasites, bacterial pneumonia, mycotic pneumonia and neoplasia.
Indications for BAL are cough, unclear or absent changes on a chest x-ray despite the manifestation of clinical signs consistent with diseases of the respiratory tract, lung neoplasms, pneumonia, stridor, removal of obstruction by bronchial mucus.
Contraindications to BAL are dyspnea (relative contraindication) and coagulopathy.
There are several criteria that guarantee that the solution enters the lower respiratory tract (bronchoalveoli): the percentage of fluid extracted and the presence of a surfactant layer.
A higher percentage of solution recovered (about 50%) indicates sampling from the lower respiratory tract. The median of the extracted solution in dogs is 42-48%, in cats 50-75%. In turn, a small amount of extracted liquid (< 40%) говорит о том, что проба взята из крупных дыхательных путей .
A surfactant (surfactant) is a phospholipid, protein, and ionic mixture secreted by type II pneumocytes into the alveolar epithelial surface to reduce alveolar surface tension. Since pulmonary surfactant in the respiratory tract is present only in the alveolar epithelial lining, the presence of surfactant in BAL fluid confirms that the samples were taken from the alveoli. In BAL samples, the surfactant appears in the form of foam (Fig. 1).
Rice. 1. Presence of a surfactant in a BAL fluid sample
Cytological analysis remains the mainstay of BAL evaluation. Normally, in a healthy animal, the BAL fluid contains macrophages, lymphocytes, neutrophils, eosinophils and mast cells.
BAL fluid samples are considered unacceptable if they have been contaminated from other areas of the respiratory tract or do not represent the bronchoalveolar environment.
Technique for performing BAL
The basic BAL technique involves infusing a sterile isotonic solution into the lower airway and aspirating the solution. BAL can be performed blindly, by passing a catheter into the lungs through an endotracheal tube, with bronchoscopic assistance, or under fluoroscopic guidance. Bronchoscopically assisted BAL allows visualization of the lower airways and directs BAL to the most affected lobes of the lungs.
Carrying out BAL in dogs
Lower respiratory tract disease in dogs results in structural changes in the bronchi (eg, thickening of the mucosa, increased exudation) and changes in the normal population of epithelial lining cells.
BAL in dogs is performed under general anesthesia. For patients undergoing BAL, it is recommended that oxygen therapy be supported during and for some time after the procedure until saturation returns to normal.
During blind oral BAL, a sterile urethral catheter is inserted into the trachea through a sterile endotracheal tube until it is gently wedged into the distal bronchus and resistance is felt. Care must be taken not to insert the catheter too far into the airway and cause iatrogenic pneumothorax, damaging the lung tissue transbronchially. After administration, 25 ml or 5 ml/kg (according to various sources) of a warm (37 C) sterile isotonic solution is injected three to five times, aspiration (transtracheal lavage) is immediately performed, and then 2-3 manual inhalations are performed with an Ambu bag. After this, the remaining liquid is aspirated by gravity or using an aspirator. Sometimes lifting the back of the animal can increase the amount of fluid extracted (Fig. 2).
Rice. 2. Raising the back of the animal to increase the amount of fluid extracted
This BAL method often provides lavage of the caudal lobes of the lungs (Fig. 3).
Rice. 3. A set of tools for performing BAL
During bronchoscopic BAL, a bronchoscope is inserted orally into the trachea. Before performing BAL, a complete bronchoscopic examination is performed. Once the area of lavage is identified, the bronchoscope is carefully wedged into the subsegmental bronchus. The tight fit of the bronchoscope to the bronchus being examined ensures maximum extraction of the injected solution. When a tight fit to the bronchus is achieved, a warm (37C°) isotonic solution is injected through the biopsy channel of the bronchoscope. It is recommended to administer a warm isotonic saline solution to reduce the risk of bronchospasm. A total of 5 to 50 ml of solution (1-2 ml/kg) is administered 1 to 4 times. Studies have found that using volume as a ml/kg weight calculation results in a larger volume of fluid recovered. Injecting a small amount of solution may not be sufficient to reach the alveoli. Once the saline solution has been injected into the airway, immediate aspiration occurs using a syringe or using an aspirator connected in series with the suction valve of the bronchoscope or with a urethral catheter through a sterile collection tube. Lack of solution during aspiration may be due to airway collapse and less force should be applied to the syringe for aspiration. If negative pressure is still present, the bronchoscope can be retracted a few millimeters, but in this case the volume of fluid obtained may be less. It is recommended to collect BAL fluid samples from several lobes of the lungs, even in cases of diffuse lung disease. In patients with focal lung lesions (aspiration pneumonia), BAL should be performed only from the affected lobe of the lung. If insufficient volume of solution is obtained or if there is no foam, the procedure should be repeated.
Humane medicine research has shown that bronchoscopically-assisted BAL provides specimens of higher diagnostic quality and reliability than unguided techniques. But the peculiarity and special attention that must be paid to the use of this technique in veterinary medicine, in our opinion, is the difficulty in preparing the instrumental channel for research to exclude contamination of BAL samples by the flora of the instrumental channel of the bronchoscope.
Carrying out BAL in cats
Rice. 4. Carrying out BAL on a cat
The smaller size of the respiratory tract in cats makes bronchoscopy difficult. This is associated with a greater number of complications compared to other animal species. For example, in a retrospective review of flexible bronchoscopy and BAL in cats at a veterinary center, there was a 38% complication rate compared with 5% in humans. The majority (24%) of complications in this review were considered mild (eg, hemoglobin desaturation). Pre-administration of inhaled bronchodilators (salbutamol, ipratropium bromide) before BAL in cats is recommended. BAL in cats is performed similarly to BAL in dogs. The volume of the injected solution varies up to 20 ml or 3-5 ml/kg, most often 2-3 injections are sufficient (Fig. 4).
Studies comparing 2 methods of aspiration, manual and suction, have shown that suction produces more aspirated fluid and better samples, but does not affect the final results of BAL fluid analysis.
Fluoroscopy-assisted BAL
In a retrospective study, fluoroscopy-assisted BAL was performed in cats. The intubated patient was given a 0.035" hydrophilic guidewire through which an 8Fr red rubber catheter was inserted. BAL was performed by injecting twice 5 ml of sterile saline, which was aspirated with a 20 ml syringe. As a result of fluoroscopy-assisted BAL, only catheterization of the cranial right lobe of the lungs was unsuccessful, catheterization of the remaining lobes of the lungs was carried out successfully, the results of the cytological analysis met all the necessary requirements. Therefore, fluoroscopically assisted BAL may be a practical, reliable and safe technique for sampling all lung lobes except the cranial right lobe (Figs. 5, 6).
Rice. 5. Conducting fluoroscopic-assisted BAL on a dog
Rice. 6. Fluoroscopy visualization during BAL
Side effects and complications after BAL
Minor complications may include bleeding, persistent hypoxemia, bronchospasm, and vasovagal syncope. Major complications include pneumonia, arrhythmias, pneumothorax, pneumomediastinum, respiratory failure, and cardiac arrest.
All patients require supplemental oxygenation after BAL. If cyanosis or desaturation is noted, supplemental oxygenation is necessary. If supplemental oxygen is not sufficient for the patient, other causes such as bronchospasm or pneumothorax should be considered. Also, after any lavage procedure, there may be a temporary deterioration in respiratory function or cough.
Cases of spontaneous pneumothorax have been reported. Rarely, complications following BAL can be fatal; such patients either had respiratory distress before undergoing BAL or were unable to restore adequate oxygenation and ventilation after the procedure.
A 2% mortality/euthanasia rate was reported (2/101). In this study, mortality was associated with pre-BAL respiratory distress. These findings lead to the conclusion that pre-existing dyspnea is a relative contraindication to BAL. Significant bronchospasm has also been reported following BAL in dogs with eosinophilic airway disease, which was treated with bronchodilators and oxygenation. A retrospective review of flexible bronchoscopy BAL in cats reported that 6% of cats required overnight hospitalization and oxygen therapy, 3% developed pneumothorax, and 6% had mortality or euthanasia due to failure to restore ventilation after the procedure. Significantly fewer complications have been reported in cats that have previously received terbutaline 0.01 mg/kg subcutaneously over 12 to 24 hours. before bronchoscopy and BAL (8%) compared with cats that received nothing beforehand (40%). Pre-treatment with inhaled bronchodilators (salbutamol, ipratropium bromide) before BAL prevents bronchoconstriction in allergen-sensitive cats. Therefore, pre-treatment with bronchodilators prior to bronchoscopy in cats is currently recommended.
BAL fluid analysis
For best results, processing of BAL samples should be performed within one hour of collection. When evaluating cytology, lavage samples from each lobe should be evaluated separately. In one study, 37% of dogs had different results when samples from different lung lobes were evaluated.
At least 200 cells must be counted in each sample. The most common cell type isolated in BAL fluid is the alveolar macrophage. Cat BAL fluid normally contains a higher number of eosinophils compared to other species.
Most dogs with bacterial infections have neutrophilic inflammation. Dogs with chronic bronchitis most often present with mixed inflammatory or neutrophilic inflammation. An increase in the number of eosinophils (from 20% to 450%) is observed in dogs with eosinophilic bronchopneumonia. Also, mixed inflammation often occurs in the presence of fungal infections.
Neutrophilic inflammation with or without intracellular bacteria may be seen in cats with pneumonia. Cats with bronchitis or asthma often have elevated eosinophil counts. However, neutrophilic and eosinophilic inflammation are not pathognomonic of an infectious or immunological process, since both eosinophilic and neutrophilic inflammation can also be seen in neoplasia.
It is difficult to diagnose neoplasia from BAL specimens. All cells must be examined according to malignancy criteria. In a small study, cats with histologically diagnosed carcinoma showed neutrophilic inflammation, but no evidence of cancer was found in BAL fluid cytology. Another study showed significant overlap in the number of differential cells in cats with pneumonia, bronchitis, and neoplasia. For these reasons, BAL cell counts should be interpreted in conjunction with clinical signs and radiographic and bronchoscopy findings.
The respiratory tract is not normally sterile, so quantifying bacterial cells can help differentiate contamination from actual respiratory tract infection. A content of more than 1.7 * 10 3 colony-forming units per milliliter is characteristic of the presence of bacterial bronchopneumonia. All samples obtained must be analyzed for the presence of aerobes and mycoplasmas. Fungal testing should be carried out in endemic areas.
The use of PCR in species diagnosis has been reported Micoplasma, Bordetella bronchiseptica And Toxoplasma gondii. PCR results must be interpreted with caution due to the fact that Mycoplasma and Bartonella may normally be present in the oropharynx of dogs and cats. Therefore, positive results do not guarantee that these pathogens are causing the patient's current clinical signs. In addition, a negative result does not exclude the presence of infection. Although the microorganism may be present in the respiratory tract, it may not be present in the small sample used for DNA extraction, resulting in a false negative result.
Table 1.
Cytology after BAL
.
Rice. 7. Segmented neutrophils and alveolar Fig. 8. Ciliated respiratory epithelium
macrophages against the background of mucus
Rice. 9. Segmented neutrophils against the background of Fig. 10. Conglomerate of epithelial cells
eosinophilic
pink interstitial substance - mucus
Conclusions
The diagnostic value of this procedure should not be overestimated because patients with respiratory disease have increased risks associated with anesthesia and respiratory procedures. The risk of a procedure must always be weighed against the expected results. Also, as studies show, BAL accompanied by bronchoscopy has fewer complications and a greater diagnostic value of the samples obtained. The choice of technique can also be made on the basis of the material resources of the veterinary institution, but in any case, the implementation of BAL must be technically regulated and performed by trained specialists.
Literature
1. Carol R. Reinero, DVM, PhD, Diplomate ACVIM (Internal Medicine), University of Missouri–Columbia. Bronchoalveolar Lavage Fluid Collection Using a Blind Technique.
2. Standardization of Bronchoalveolar Lavage Aspiration Techniques to Optimize Diagnostic Yield of Canine Lower Respiratory Tract Samples by Katharine Sarah Woods.
3. Mills PC, Lister AL. Using urea dilution to standardize cellular and non-cellular components of pleural and bronchoalveolar lavage (BAL) fluids in the cat. J. Fel. Med. Surg. 2006; 8:105-110. Mordelet-Dambrine M., Arnoux.
4. Melamies MA, Jarvinen AK, Seppala KM, Rita HJ, Rajamaki MM. Comparison of results for weight-adjusted and fixed-amount bronchoalveolar lavage techniques in healthy Beagles. Am. J. Vet. Res. 72:694–698, 2011.
5. Chalker VJ, Owen WM, Paterson C, et al. Mycoplasmas associated with canine infectious respiratory disease. Microbiology 150:3491–3497, 2004.
6. Creevy KE. Airway evaluation and flexible endoscopic procedures in dogs and cats: laryngoscopy, trans-tracheal wash, tracheobronchoscopy, and bronchoalveolar lavage. Vet Clin North Am Small Anim Pract 2009; 39:869-880
7. Spector D, Wheat J, Beamis D, Rohrbach B, Taboada T, Legendre AM. Antigen testing for the diagnosis of Blastomycosis. J Vet Intern Med 20:711–712, 2006.
8. Egberink H, Addie D, Belak S, et al. Bordetella bronchiseptica infections in cats. J Fel Med Surg 11:610–614, 2009.
9. Anfray P, Bonetti C, Fabbrini F, Magnino S, Mancianti F, Abramo F. Feline cutaneous toxoplasmosis: a case report. Vet Dermat 16:131–136, 2005.
10. American Thoracic Society. Bronchoalveolar lavage guidelines. Jul 8, 2012.
11. Hawkins EC, Berry Cr. Use of a modified stomach tube for bronchoalveolar lavage in dogs. J Am Vet Med Assoc 1999; 215(11):1635-1638.
12. Hawkins EC, Davidson MG, Meuten DJ, et al. Cytologic identification of Toxoplasma gondii in bronchoalveolar lavage fluid of experimentally infected cats. J Am Vet Med Assoc 1997; 210(5):648-650.
13. Hawkins EC, DeNicola DB. Cytologic analysis of tracheal wash specimens and bronchoalveolar lavage fluid in the diagnosis of mycotic infections in dogs. J Am Vet Med Assoc 1990a; 197(1):79-83.
14. Hawkins EC, DeNicola DB, Kuehn NF. Bronchoalveolar lavage in the evaluation of pulmonary disease in the dog and cat: state of the art. J Vet Intern Med 1990b; 4:267-274.
15. Hawkins EC, DeNicola DB, Plier ML. Cytological analysis of bronchoalveolar lavage fluid in the diagnosis of spontaneous respiratory tract disease in dogs: a retrospective study. J Vet Intern Med 1995; 9:386–392.
16. Johnson LR, Drazenovich TL. Flexible bronchoscopy and bronchoalveolar lavage in 68 cats (2001–2006). J Vet Int MEd 2007; 21:219–225.
17. Silverstein DC, Drobratz KJ. Clinical evaluation of the respiratory tract. In: Ettinger SJ, Feldman EC, eds. Textbook of veterinary internal medicine. 7th ed. Saunders Elsevier: St Louis, 2010:1055–1066.
18. Yoneda KY, Morrissey BM. The technique of adult flexible bronchoscopy: part 1. J Respir Dis 2008; 29(11):423-428.
19. Hawkins EC. Bronchoalveolar lavage. In: King LG, ed. Textbook of respiratory disease in dogs and cats. Saunders Elsevier: St Louis, 2004:118-128.
20. Cooper ES, Schober KE, Drost WT. Severe bronchoconstriction after bronchoalveolar lavage in a dog with eosinophilic airway disease. J Am Vet Med Assoc 2005; 227(8):1257-1262.
21. Johnson LR, Queen EV, Vernau W, et al. Microbiologic and cytologic assessment of bronchoalveolar lavage fluid from dogs with lower respiratory tract infection: 105 cases (2001-2011). J Vet Intern Med 2013;27(2):259-267.
22. Kirschvink N, Leemans J, Delvaux F, et al. Bronchodilators in bronchoscopy induced airflow limitation in allergen-sensitized cats. J Vet Intern Med 2005;19:161-167.
23. Padrid PA. Laryngoscopy and tracheobronchoscopy of the dog and cat. In: Tams TR, Rawlings CA, eds. Small Animal Endoscopy. St. Louis, MI: Elsevier Mosby, 2011:331-359.
24. Fluoroscopic-Guided Bronchoalveolar Lavage (F-Bal) for Sampling the Lower Airways of Cats Hooi KS1, Defarges A1, Nykamp S1, Weese S2, Bienzle D2. Departments of Clinical Studies1 and Pathobiology2, University of Guelph, ON.
