Introduction:
Bronchopulmonary sequestration (BPS) is a rare congenital disease that affects the respiratory system, presenting unique challenges for both patients and healthcare providers. This congenital malformation involves abnormal lung tissue development, leading to a mass or cyst that does not communicate with the normal bronchial tree and receives its blood supply from abnormal vessels. This article briefly explains bronchopulmonary sequestration, its causes, types, symptoms, diagnosis, and treatment.
What Is Bronchopulmonary Sequestration?
Bronchopulmonary sequestration is a rare congenital anomaly characterized by the presence of non-functional lung tissue that lacks a connection to the normal airway. Essentially, it is a mass or cyst that receives its blood supply from systemic vessels rather than the pulmonary arteries. This abnormality typically manifests in the lower lobes of the lungs.
What Causes Bronchopulmonary Sequestration?
Bronchopulmonary sequestration occurs during fetal development when a portion of the lung tissue becomes isolated from the normal bronchial tree. This non-functional lung tissue then forms a mass that receives its blood supply from systemic vessels rather than the pulmonary artery.
What Are the Types of Bronchopulmonary Sequestration (BPS)?
BPS is classified into two main types: intralobar and extralobar.
Intralobar Bronchopulmonary Sequestration: This type is more common and has a reported incidence of 75 percent to 86 percent among all sequestration cases. It involves a mass of abnormal lung tissue within a normal lung lobe. Intralobar BPS shares a common pleural covering with the surrounding lung tissue.
Extralobar Bronchopulmonary Sequestration: Extralobar BPS is rarer and involves a separate mass of lung tissue with its pleural covering. The mass is often located outside the normal lung tissue, usually in the chest cavity.
What Are the Symptoms of Bronchopulmonary Sequestration (BPS)?
The symptoms of BPS may vary depending on the type of bronchopulmonary sequestration.
1. Intralobar Sequestration:
Frequently Asymptomatic: Many individuals do not experience any symptoms and are diagnosed incidentally during chest CT (computed tomography) scans.
Recurrent Pneumonia: The most common presentation, often affecting a specific area of the lung.
Persistent Cough: This can be a chronic symptom, separate from or accompanying pneumonia.
Back Pain: This may be associated with the location of the sequestrated tissue.
Persistent Exertional Shortness of Breath: Difficulty breathing during physical activity.
Hemoptysis: Coughing up blood occurs more frequently than with extralobar sequestration.
2. Extralobar Sequestration: Extralobar sequestration is usually manifested clinically in early infancy with
Respiratory Distress: Difficulty breathing, often noticeable soon after birth.
High Output Congestive Heart Failure: Caused by a blood flow abnormality.
Occasional Spontaneous Pulmonary or Pleural Hemorrhage: Bleeding in the lungs or surrounding space.
Rarely Infected: Due to separation from the airway system by surrounding tissue.
How Is Bronchopulmonary Sequestration Diagnosed?
Diagnosing bronchopulmonary sequestration often involves the following:
Chest X-ray: Provides initial clues, especially for intralobar sequestration in young patients with recurrent infections.
Computed Tomography (CT) Scan: Highly accurate (90 %) for both types of sequestration, especially with 3D reconstruction and contrast. The current gold standard for non-invasive diagnosis.
Magnetic Resonance Imaging (MRI) and MR Angiography (MRA): Similar information to CT scans but less widely used.
Ultrasonography: Ideal for prenatal and postnatal settings, especially with color flow and duplex Doppler for identifying abnormal blood supply.
Radionuclide Angiography: Demonstrates systemic arterial blood supply to the sequestration, confirming diagnosis.
Angiography: This invasive procedure involves injecting a contrast dye into the blood vessels to visualize the blood supply to the anomalous lung tissue. The definitive diagnosis is made by using angiography. Angiography helps differentiate pulmonary sequestration from other abnormalities of the lung. Bleeding in the lungs must be interpreted along with clinical and chest radiographic findings.
Doppler Ultrasound: Can detect sequestration as early as 18 to 19 weeks gestation.
What Are the Possible Complications of Bronchopulmonary Sequestration?
Bronchopulmonary sequestration can lead to the following complications:
Growth abnormalities.
Hemorrhagic pleural effusion.
Recurrent infection is common in intralobar sequestration.
Rare cases of extra lobar sequestrations communicating with the GI (gastrointestinal) tract have been reported. They are known as congenital bronchopulmonary foregut malformations (CBPFM).
Development of malignant tumors within intralobar sequestration.
What Is the Treatment of Bronchopulmonary Sequestration?
The management of bronchopulmonary sequestration depends on various factors, including the patient's age, the presence of symptoms, and the size and location of the sequestration.
1. Early Intervention:
Hospitalization and Intensive Care: Specialized treatment is crucial due to potential complications like pulmonary hypoplasia (underdeveloped lungs).
Thoracoamniotic Shunting: For fetuses with hydrops (fluid accumulation) before 30 weeks gestation, this procedure helps drain excess fluid.
Postnatal Support: Depending on severity, newborns may require ventilator support, high-frequency oscillatory ventilation, or even extracorporeal membrane oxygenation (ECMO).
Tube Thoracostomy: This procedure drains large pleural effusions (fluid around the lungs) in severe cases.
Surgical Resection: Ultimately, surgery to remove the sequestered tissue is recommended, even for asymptomatic infants, to prevent future infections and inflammation. However, in certain cases with pulmonary hypoplasia and hypertension, surgery may be delayed until stabilization occurs.
2. Pulmonary lobectomy: The preferred treatment for symptomatic patients, even in some asymptomatic cases, to avoid complications.
3. Surgery Options:
Open Thoracotomy: Traditional open chest surgery approach.
Video-Assisted Thoracoscopic Surgery (VATS): Minimally invasive approach with smaller incisions, leading to potentially faster recovery times and fewer complications. Recent advancements even include uniportal VATS, requiring only one small incision.
4. Endovascular Embolization: This minimally invasive technique involves blocking blood flow to the sequestered tissue using coils or other embolic agents like particles, glue, plugs, or alcohol. This leads to shrinkage and eventual disappearance of the tissue.
What Is the Differential Diagnosis of Bronchopulmonary Sequestration?
Symptoms of bronchopulmonary sequestration (BPS) can mimic many other lung conditions, for example:
Cystic adenomatoid malformation (non-cancerous overgrowth of abnormal lung tissue).
Bronchogenic cyst (congenital abnormality arising from an abnormal budding of the tracheobronchial tree).
Focal bronchiectasis (usually occurs when the bronchi (large airway) become dilated).
Congenital lobar emphysema (developmental abnormality of lungs characterized by overinflation of a lung lobe due to a blockage of the airways).
Retroperitoneal tumors in extra lobar abdominal sequestrations.
Conclusion:
Bronchopulmonary sequestration, though rare, highlights the complexity of congenital anomalies affecting the respiratory system. Timely and accurate diagnosis is crucial for appropriate management decisions. Advances in imaging technology and surgical techniques have improved outcomes for individuals with BPS, offering hope for a healthier and more comfortable life. As research continues to uncover the intricacies of such anomalies, healthcare professionals can refine their approach to diagnosis, treatment, and long-term care for those affected by bronchopulmonary sequestration.
