93: Pulmonary Sequestration

Introduction

Pulmonary sequestration is a congenital syndrome characterized by abnormal systemic blood supply to the lung, usually the lower lobe. The anomaly causes a predisposition for pulmonary complications such as infection and hemoptysis. There are two types of sequestrations, intralobar and extralobar. As the name implies, the intralobar sequestration is located within the normal lung (Fig. 93-1), whereas the extralobar sequestration is separate from the normal lung, enclosed in its own pleural envelope (Fig. 93-2). One should be aware of the various other associated anomalies, such as abnormal communication of the bronchial tree, systemic venous drainage, rare communication to the foregut, and diaphragmatic hernia (Table 93-1). In addition, the aberrant systemic vessel can arise from any systemic intrathoracic or upper abdominal vessel, such as the aorta, the subclavian artery, and even the coronary arteries. While they are found most commonly in the lower lobes, left more often than right, sequestrations also can occur in the right or left upper lobe.

Clinical Presentation

Extralobar pulmonary sequestrations tend to present at an early age with respiratory distress because they are associated with other congenital anomalies, such as diaphragmatic hernias. They have systemic venous drainage and no bronchial communication. In contrast, intralobar sequestrations are commonly diagnosed in adulthood, present with frequent pulmonary infections or hemoptysis, have pulmonary venous drainage and a normal bronchial communication, and are rarely associated with other anomalies.^1–3 Fever, cough, multiple pulmonary infections, and hemoptysis can occur, although up to 13% can be asymptomatic.⁴ The affected lobe tends to develop chronic changes owing to recurrent infections with eventual cystic destruction of the parenchyma. A chest x-ray that reveals consolidation along the medial aspect of the lower lobe should arouse suspicion of a sequestration. A chest computed tomography (CT) scan can confirm the diagnosis of the sequestration, and ...