Bronchoalveolar lavage

BAL is diagnostic procedure done by pulmonologists using bronchoscope to diagnose various lung diseases

1. Bronchoalveolar Lavage Dr Dileep MD Asst. Professor Pulmonary Medicine Mediciti Medical College Hyderabad

2. Introduction Procedure Analysis Complications Limitations of BAL Diagnostic Role

3. Introduction The most commonly employed bronchoscopic techniques for sampling airways & alveolar spaces include: 1. B ronchial washings 2. Bronchial brushings 3. Bronchoalveolar lavage (BAL) Bronchoalveolar lavage is safe noninvasive means of sampling both cellular & acellular components of lung parenchyma It is safe even in critically ill pts where biopsy & brushings may not be recommended due to risk of bleeding

4. Procedure By instilling sterile 0.9% NaCl via a channel of FOB, which has been wedged into a bronchus Total of 100-300ml of NaCl can be instilled for adequate sampling of a pulmonary subsegment and about 40-60% of injected volume is recovered usually Prewarming the lavage fluid to 37” C may help prevent coughing, especially in patients with hyperresponsive airways When the disease is focal, lavage should be directed to the site of greatest abnormality When the disease is diffuse, lavage of middle lobe, lingula / lower lobes allows for better fluid recovery

5. BAL fluid Analysis Detection of alveolar hemorrhage Microbiological testing-Gram stain, C/S Cytological analysis Cell count TC, DC PCR for organism specific DNA Flow cytometry Evaluation of immunological parameters & tissue markers

6. Complications Fever 2.5% -due to release of proinflammatory cytokines from activation of alveolar macrophages ,rather than infection Pneumonitis-0.4% Hemorrhage -0.7% Bronchospasm -0.7% Focal areas of consolidation corresponding to region undergoing lavage , subsides within 24 hrs

7. Limitations of BAL Large range of normal values for each parameter makes BAL insensitive Abnormalities of BALF are not specific for any of the ILDs

8. PULMONARY INFECTION Immunocompromised host VAP Non-resolving Pneumonia DPLD Alveolar hemorrhage Sarcoidosis Pulmonary alveolar proteinosis Eosinophilic pneumonia Drug toxicity PLCH Hypersensitivity pneumonitis Idiopathic pulmonary fibrosis PULMONARY MALIGNANCY Lymphangitic carcinomatosis Bronchoalveolar carcinoma Other malignancies OCCUPATIONAL LUNG DISEASE Chronic beryllium disease Asbestosis PEDIATRIC LUNG DISEASE Infection Interstitial Lung Disease Aspiration Hemorrhage Cystic fibrosis POSTTRANSPLANT MONITORING OF THE LUNG ALLOGRAFT BAL : Diagnostic Role

9. BAL in Pulmonary Infections Useful in both immunocompetent and immunocompromised patients Uncentrifuged BAL fluid: quantitative bacterial culture Cytospin preparations can be stained to detect the presence of bacteria, Pneumocystis carinii , mycobacteria , or fungi Useful in detecting causative organism in VAP-Positive bacterial cultures - >10^4 CFU/ml Immunofluorescent staining / PCR methods can provide rapid diagnosis BAL combined with PCR is useful in the diagnosis of pulmonary tuberculosis in smear-negative patients

10. BAL in DPLD BAL differential cell counts can support the diagnosis of specific ILD, however with low specificity and sensitivity Cell findings in BALF are non specific in most cases A BAL of a healthy nonsmoker adult yields 80% to 95% macrophages 5% to 15% lymphocytes (CD4/CD8 ratio of 1.5–1.8) less than 3% neutrophils less than 1% eosinophils and mast cells

11. Bronchoalveolar Lavage Cellular Changes Associated with DPLD Lymphocytes (15%) Sarcoidosis Hypersensitivity pneumonitis CVD-associated ILD Drug-induced pneumonitis IIP (NSIP-cellular, COP) Occupational disease (e.g., chronic beryllium disease) Infection ( mycobacteria , viral) Radiation pneumonitis Neutrophils (5%) Infection Lung injury IIP (COP, DIP, IPF, NSIP) CVD-associated ILD Drug-induced pneumonitis Occupational lung disease Aspiration pneumonia Semin Respir Crit Care Med 2007

12. Eosinophils (3%) Eosinophilic pneumonia Drug-induced pneumonitis Churg -Strauss syndrome Hypereosinophilic syndrome Parasitic infection CVD-associated ILD Pneumocystis pneumonia Bronchoalveolar Lavage Cellular Changes Associated with DPLD Semin Respir Crit Care Med 2007

13. Use of flow cytometry Increased (5% of total cells) CD1a-positive cells can support diagnosis of pulmonary Langerhans cell histiocytosis (PLCH) CD4+ : CD8+ ratio > 3.5 has been shown to be fairly specific for sarcoidosis , however, the sensitivity is relatively low CD4+ : CD8+ ratio < 1 has been reported for HP, drug-induced lung disease , COP, EP, IPF

14. DISEASE FINDINGS IN BAL Pulmonary Alveolar Proteinosis Lipoproteinaceous material that looks milky & sandy, stains + ve with PAS Pulmonary Alveolar Microlithisiasis Looks milky & sandy, centrifuging demonstrates sedimentation Pulmonary langerhans cell granulomatosis >5%langerhans cells,Birbeck granules Asbestosis Ferruginous bodies Silicosis Dust particles on polarised microscopy Berylliosis + ve lymphocyte transformation test Some drugs Foamy macrophages Diffuse alveolar hemorrhage Hemosiderin laden macrophages(>20%) Lipoid pneumonia Fat globules in macrophages Malignancy Malignant cells

15. BAL in Pulmonary Malignancy Can increase the diagnostic yield of FOB in peripheral lesions in bronchogenic carcinoma Positivity rates vary between 47-69% BAL can be useful in bronchoalveolar carcinoma, lymphangitic carcinoma, and infiltration of the lung with hematological malignancies

16. BAL in Occupational Lung Disease Although silica particles or asbestos fibers can be detected in BAL, it alone cannot differentiate exposure from disease Chronic beryllium disease: lymphocytic alveolitis + beryllium-sensitized lymphocytes from BAL is diagnostic

17. BAL in Children The constituents of BAL fluid similar to adults Detection of lipid-laden macrophages is suggestive of aspiration Measurement of pepsin levels in BAL, is quite specific for GE reflux BAL has also been used to study cystic fibrosis extensively

18. BAL and Lung Allograft Routinely performed along with TBLB for surveillance or diagnostic purposes in acute deterioration in graft function Useful tool for the detection of infection Upto 3 months after transplant BAL neutrophilia occurs as a consequence of reperfusion injury Techniques to diagnose chronic/acute rejection via microarray analysis of BAL cell gene expression or BAL fluid protein analysis are being investigated

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