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Journal of Postgraduate Medicine, Vol. 49, No. 3, July-Sept, 2003, pp. 280-281 Images in Radiology Bronchopulmonary Sequestration Veerappan GR, Lettieri CJ
Department of Internal Medicine, Walter Reed Army Medical
Center, 6900 Georgia Ave, Washington, DC 20307, USA. Code Number: jp03076 A forty-seven year-old woman, non-smoker, initially presented four months prior with a non-productive cough and fever. A chest radiograph revealed a right lower lobe infiltrate. She completed two courses of antimicrobials without significant improvement. On follow-up, her vital signs, physical examination, spirometry, and complete blood count were within normal limits. A repeat chest radiograph revealed an unchanged right lower lobe consolidation. A detailed history revealed recurrent pneumonias since adolescence. She denied haemoptysis, any known history of tuberculosis exposure or risk factors for HIV infection. The persistent opacity in the same anatomic location raised the suspicion of anatomic abnormalities, bronchogenic cyst, chronic aspiration, diaphragmatic hernia and bronchopulmonary sequestration. The persistence of symptoms despite antimicrobials, also raised concern about lung abscess and resistant or indolent infection. Bronchioalveolar lavage revealed a normal cell count and was negative for acid-fast bacilli, fungi and bacteria. Computed tomography (CT) demonstrated an aberrant aortic branch supplying a consolidated right lower lobe [Figure-1] and [Figure-2]. Bronchopulmonary sequestration was suggested by the persistent lower lobe infiltrate and confirmed by demonstrating the aberrant arterial supply. DISCUSSION Bronchopulmonary sequestrations are congenital anomalies that may present in adults as recurrent pneumonia in a persistent location. These foregut malformations result in non-functioning pulmonary tissue with inadequate tracheobronchial communication and insufficient drainage, which predisposes to infection. The sequestration has aberrant systemic, rather than pulmonic, arterial supply.[1] Multiple aberrant arteries are seen in 15-20% of the cases.[2] Bronchopulmonary sequestrations are divided into intralobar and extralobar. Intralobar sequestrations are surrounded by normal lung parenchyma without separate pleura. They comprise 75% of all sequestrations, are typically diagnosed in adulthood, and have equal gender distribution.[3] The aberrant artery typically originates from the thoracic aorta, but venous drainage is pulmonic. In contrast, extralobar sequestrations are enclosed within their own visceral pleura, are more commonly seen in males, usually diagnosed in infancy or childhood and almost uniformly occur in the left lower lobe.[4] Other congenital anomalies, such as bronchogenic cysts and diaphragmatic hernias, are associated in 60% of cases.[4] Arterial supply is typically from the abdominal aorta with systemic venous drainage.[5] Intralobar sequestration typically presents in adults as recurrent lower lobe pneumonia. In such cases, recurrent pneumonia in a characteristic location raises the suspicion of bronchopulmonary sequestration, while the final diagnosis is established by demonstrating aberrant arterial supply. Arteriography is considered the gold standard for identification of the aberrant artery. Newer, less invasive imaging techniques are equally effective and safer alternatives to angiography. These include CT angiography, Doppler ultrasound, and Magnetic Resonance Angiography (MRA). Colour-enhanced, three-dimensional MRA can identify both the arterial and venous aberrancies and define the soft tissue abnormalities associated with sequestration.[6],[7] Multiplanar, three-dimensional reconstruction of the CT angiogram can demonstrate the entire route of the anomalous vessel and define the consolidation of the sequestered lobe.[2] These less invasive imaging techniques can provide additional information over traditional angiography and they should be used routinely in the preoperative evaluation of sequestrations. Therapeutic options include surgical resection and arterial embolization. Surgical resection is curative and should be considered to prevent recurrent infections and haemoptysis. Arterial embolization provides an alternative to surgery and has been performed successfully in children.[7] Its use in adults remains controversial, but has been used to control massive haemoptysis prior to surgery. In the present case, CT revealed a right basal infiltrate with aberrant blood supply, confirming the diagnosis of intralobar sequestration. CT multiplanar, three-dimensional reconstruction precisely identified the arterial supply and guided surgical excision. Our patient completed a 6-week course of antimicrobials followed by a right lower lobectomy with excellent results and is well on follow-up. REFERENCES
Copyright 2003 - Journal of Postgraduate Medicine. Online full-text also available at http://www.jpgmonline.com/ The following images related to this document are available:Photo images[jp03076f1.jpg] [jp03076f2.jpg] |
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