Introduction: Why Your Lungs Deserve a Closer Look
When your chest X-ray or CT scan shows something concerning, or when a persistent cough, breathlessness, or unexplained lung infection refuses to resolve, your pulmonologist may recommend a procedure called flexible bronchoscopy. This minimally invasive diagnostic tool has transformed modern respiratory medicine, giving doctors a direct window into the airways and lungs to pinpoint the exact cause of your symptoms.
Flexible bronchoscopy is not just a single procedure — it is a platform through which several advanced techniques can be performed simultaneously: Bronchoalveolar Lavage (BAL), Bronchial Brush Biopsy, and Forceps Biopsy. Together, these techniques allow accurate diagnosis of infections, cancers, inflammatory diseases, and rare pulmonary conditions that would otherwise remain a mystery.
In this blog, we walk you through everything you need to know about flexible bronchoscopy — what it is, how each sampling technique works, what conditions it diagnoses, and what to expect before, during, and after the procedure.
What Is Flexible Bronchoscopy?
Flexible bronchoscopy is a medical procedure in which a thin, flexible tube called a bronchoscope is inserted through the nose or mouth, down through the throat and vocal cords, into the trachea (windpipe), and into the bronchial tubes of the lungs. The bronchoscope has a camera and a light at its tip, transmitting real-time video to a monitor so the doctor can visually examine the entire airway.
Unlike rigid bronchoscopy (used mainly in operating theatres for therapeutic interventions), flexible bronchoscopy can be performed under conscious sedation in an endoscopy suite or bronchoscopy unit, making it far more accessible and comfortable for patients.
The procedure typically takes 20 to 45 minutes and allows the pulmonologist to:
- Directly visualize the airways including the vocal cords, trachea, and all major bronchi
- Identify abnormalities such as tumors, inflammation, bleeding, or foreign bodies
- Collect tissue and fluid samples for laboratory analysis
- Perform therapeutic maneuvers in selected cases
The Three Core Sampling Techniques
1. Bronchoalveolar Lavage (BAL)
Bronchoalveolar Lavage, commonly known as BAL, is a technique in which sterile saline (salt water) is instilled into a segment of the lung through the bronchoscope and then gently suctioned back. This lavage fluid contains cells and microorganisms from the deep alveolar (air sac) spaces, providing a rich sample for analysis.
What BAL Diagnoses: BAL is invaluable for diagnosing respiratory infections (including tuberculosis, Pneumocystis jirovecii pneumonia, fungal infections, and viral pneumonitis), interstitial lung diseases such as hypersensitivity pneumonitis and sarcoidosis, and in immunocompromised patients where identifying the causative organism is critical.
How It Works: The bronchoscope is gently wedged into a subsegmental bronchus. About 100 to 200 ml of saline is instilled in small aliquots and immediately aspirated. The recovered fluid (typically 40 to 60%) is sent to the microbiology, cytology, and cell differential labs.
What You May Feel: During BAL, you may experience a mild sensation of fluid in the chest and a brief urge to cough. Sedation significantly minimizes discomfort.
2. Bronchial Brush Biopsy
The brush biopsy technique involves advancing a small cytology brush through the working channel of the bronchoscope to scrape cells from the surface of abnormal airways or visible lesions. The brush is then withdrawn and the cells are smeared onto glass slides or placed in a liquid medium for cytological examination.
What Brush Biopsy Diagnoses: This technique is particularly effective for diagnosing endobronchial (airway-lining) cancers, pre-malignant lesions, and infections involving the bronchial walls. It complements BAL and forceps biopsy to improve the overall diagnostic yield.
Why It Matters: Brush biopsy increases the chances of capturing malignant cells from tumors that grow along the airway surface. Combined with forceps biopsy, sensitivity for lung cancer diagnosis can exceed 90% for centrally located tumors.
3. Endobronchial and Transbronchial Biopsy
Biopsy using small forceps passed through the bronchoscope allows the doctor to obtain actual tissue specimens, not just cells. Two types are performed:
Endobronchial Biopsy: Tissue is taken directly from a visible abnormality within the airway — such as a tumor, granuloma, or inflamed mucosa.
Transbronchial Biopsy (TBB): The forceps are advanced beyond the visible airways into the lung parenchyma to sample peripheral lung tissue — invaluable for diagnosing diffuse infiltrative lung diseases like sarcoidosis, organizing pneumonia, and hypersensitivity pneumonitis.
Both techniques provide a histological (tissue-level) diagnosis, offering far greater detail than cytology alone.
Conditions Diagnosed by Flexible Bronchoscopy with BAL, Brush, and Biopsy
- Lung cancer (squamous cell carcinoma, adenocarcinoma, small cell carcinoma)
- Pulmonary tuberculosis and atypical mycobacterial infections
- Pneumonia unresponsive to standard treatment
- Fungal infections (Aspergillosis, Cryptococcosis, Candida)
- Sarcoidosis and other granulomatous lung diseases
- Interstitial lung disease (ILD) including UIP and NSIP patterns
- Organizing pneumonia and eosinophilic lung disease
- Immunocompromised patient workup (post-transplant, HIV-related, chemotherapy-induced)
- Foreign body detection and removal
- Evaluation of hemoptysis (coughing blood)
Preparing for Your Bronchoscopy
Preparation is simple but important. Your pulmonologist will advise you to fast for at least 4 to 6 hours before the procedure. Blood thinners may need to be paused, and you will need to arrange for someone to drive you home afterward since sedation will affect your reflexes.
On the day of the procedure, a local anesthetic spray is applied to the throat, and sedation is administered through an intravenous line. Oxygen and vital sign monitoring are maintained throughout.
Recovery and After-Care
Most patients can go home within 1 to 2 hours after the procedure. A mild sore throat, slight hoarseness, and occasional blood-tinged mucus are normal for 24 hours. You will be asked to avoid eating or drinking until the throat numbness wears off. Results from BAL and brush cytology are often available within 48 to 72 hours, while biopsy histology may take 5 to 7 days.
Frequently Asked Questions (FAQs) — Flexible Bronchoscopy
Q1: Is flexible bronchoscopy painful?
The procedure is performed under conscious sedation, so most patients feel minimal discomfort. Local anesthetic is sprayed in the throat to reduce the gag reflex. You may feel slight pressure or an urge to cough, but most patients tolerate it very well.
Q2: How long does the procedure take?
Flexible bronchoscopy typically takes 20 to 45 minutes, depending on the number of sampling techniques used. Including preparation and recovery, plan for a half-day visit.
Q3: What is the difference between BAL, brush, and biopsy?
BAL collects fluid and cells from deep lung spaces (alveoli), brush biopsy scrapes cells from airway surfaces, and forceps biopsy removes small tissue fragments. All three together maximize diagnostic accuracy.
Q4: Are there risks involved in bronchoscopy?
Flexible bronchoscopy is generally very safe. Minor risks include temporary low oxygen levels, mild bleeding from biopsy sites, and a small risk of pneumothorax (air leak) with transbronchial biopsy (<2%). Serious complications are rare and are managed promptly by experienced teams.
Q5: When will I get my results?
BAL microbiology and cytology results are typically available in 48 to 72 hours. Bacterial cultures take up to 5 days, and histopathology from biopsy specimens usually takes 5 to 7 days.
Q6: Can bronchoscopy detect lung cancer?
Yes. For centrally located tumors within visible airways, the combination of BAL, brush, and biopsy can detect lung cancer with sensitivity greater than 85 to 90%. For peripheral tumors, additional techniques like EBUS (endobronchial ultrasound) may be combined.
Q7: Who performs flexible bronchoscopy?
Flexible bronchoscopy is performed by trained pulmonologists (respiratory physicians) with specialized bronchoscopy certification, usually in a dedicated bronchoscopy suite with full monitoring and emergency support.