Introduction
A lung biopsy is performed to diagnose lung nodules, masses, and other pulmonary disorders, including sarcoidosis, pneumonitis, interstitial lung disease, and infections like tuberculosis. Various techniques of lung biopsy are performed depending on the requirement. A transbronchial biopsy is a lung biopsy that uses a bronchoscope (a device that uses a thin tube to examine the airways and the lungs) to obtain a sample of lung tissue. A transbronchial biopsy helps in determining the specific characteristics of a lung lesion.
What Does a Lung Biopsy Mean?
Lung biopsy is a widely accepted diagnostic procedure that is performed to diagnose a wide variety of lung disorders. Samples are obtained from the lung tissues for histopathological examination. A lung biopsy is performed when there is a need for a specific diagnosis or when the etiology is not clear. Various techniques are performed to obtain lung tissue for examination. It includes open lung biopsy, percutaneous transthoracic lung biopsy, video-assisted thoracic surgery, transbronchial biopsy, and cryo biopsy. Cone beam CT (computed tomography), robotic bronchoscopy, electromagnetic navigation bronchoscopy, and endobronchial ultrasound biopsy are recent advancements in the field of transbronchial biopsy.
What Is Transbronchial Biopsy?
The term transbronchial refers to the procedure performed via the bronchus (one of the tubular structures that carry air to the lungs). A transbronchial lung biopsy is a procedure performed to diagnose focal and diffuse diseases of the lung. Initially, a lung biopsy was performed by means of open surgical techniques until 1963. Later, the transbronchial biopsy was performed using a rigid bronchoscope. In 1974, Levin et al. performed a transbronchial biopsy with a flexible bronchoscope and shared their experience. A transbronchial biopsy helps determine various lung diseases, including infections, tumors, polyps, and cancer, from the lung tissue sample obtained. It is usually performed to diagnose interstitial lung disease or to specify the characteristics of the lesion from the samples obtained from the peripheral lung lesion.
What Are the Indications of Transbronchial Biopsy?
A transbronchial biopsy is usually performed to determine the etiology of nodules and masses in the lungs and to diagnose focal and diffuse lesions of the lung. A transbronchial biopsy is indicated in the following conditions:
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Sarcoidosis (a disorder in which there is a growth of tiny groups of inflammatory cells in any part of the body).
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Hypersensitivity pneumonitis (an immune system disorder characterized by lung inflammation in response to allergic reactions).
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Neoplastic diseases (abnormal growth of cells that cause cancerous and noncancerous diseases).
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Pulmonary infections, like tuberculosis.
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Eosinophilic pneumonia (a group of disorders in which there is a buildup of eosinophilic infiltrates in the parenchyma of the lungs).
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Lung diseases of unclear etiology.
What Are the Contraindications of Transbronchial Biopsy?
Absolute contraindications include:
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Severe hypoxia (low levels of oxygen in the body tissues).
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Malignant arrhythmia (ventricular arrhythmias that result in cardiovascular collapse).
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Status asthmaticus (severe asthma exacerbation that results in respiratory failure).
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Massive hemoptysis (coughing up blood).
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Medical instability.
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Lack of patient cooperation.
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Bleeding diathesis.
Relative contraindications include:
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Uremia.
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Pulmonary hypertension.
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Risk of arrhythmia.
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Mechanical ventilation.
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Antiplatelet drugs.
In relatively contraindicated conditions, a transbronchial biopsy can be performed with caution.
How Is Transbronchial Biopsy Performed?
A transbronchial biopsy is performed using a flexible bronchoscope. It is performed after topical anesthesia and conscious sedation. An imaging technique called fluoroscopy is used as an adjunct to this procedure. A flexible telescope with a tiny camera is used to examine the airways. A bronchoscope (a flexible tube) is passed through the nose or the mouth and down to reach the lungs. Further, tiny forceps are passed down through one of the airways to reach the lungs. This forceps is used to obtain tissue samples. Saline fluid helps in flushing the cells and in collecting their cells.
All the segments of the lungs are thoroughly inspected to exclude endobronchial abnormalities. The bronchoscope is wedged in the area to be examined, and the biopsy forceps are passed to enter the lung segment. The fluoroscopy unit allows visualization of the forceps. The forceps are then advanced to obtain the lung tissue sample.
This procedure is usually performed as an outpatient procedure, and the recovery process after this procedure is painless and relatively quick. It may cause throat discomfort and pain during swallowing for a few days.
What Are the Complications of Transbronchial Biopsy?
Though transbronchial biopsy helps in obtaining a sample of lung tissue, it can also cause potentially fatal complications. The major complications associated with transbronchial biopsy are pneumothorax and bleeding. Pneumothorax is a condition in which air leaks into the space between the chest wall and the lungs. It occurs in one to six percent of patients. The risk of pneumothorax can be minimized by placing the biopsy forceps near the lung surface and not at the lung surface. Other rare complications include subcutaneous and mediastinal emphysema (the presence of air under the skin and the space between the lungs).
What Is the Significance of Transbronchial Biopsy?
Transbronchial biopsy is a widely accepted conventional method of lung biopsy. It is a safe procedure with a 0.1 percent mortality rate compared to surgical lung biopsy with a one percent mortality rate. It can be performed for central lesions that are accessible. In addition, a transbronchial biopsy does not require general anesthesia and can be performed as an outpatient procedure. It is also highly sensitive in the diagnosis of lipoid pneumonia, eosinophilic pneumonia, drug-induced pneumonitis, Langerhans cell histiocytosis, pulmonary alveolar proteinosis, bronchoalveolar carcinoma, and lymphangitic spread of the tumor. Also, the diagnostic yield can be increased by combining this technique with CT guidance.
However, this technique is not as sensitive as percutaneous biopsy because of lesions that are less than two centimeters in diameter. The diagnostic accuracy of transbronchial biopsy increases when the lesion is larger than two centimeters in diameter. In order to improve the diagnostic yield of transbronchial biopsy, endobronchial ultrasound was introduced. Endobronchial ultrasound helps in determining the detailed images of bronchial and parabronchial structures.
Conclusion
A transbronchial biopsy is a procedure performed to diagnose focal and diffuse lesions of the lungs and other pulmonary diseases. It is a widely accepted method and is safe compared to open surgical techniques. It is a highly sensitive technique with advancements in imagining and guidance technologies.
