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Genetic and Rare Diseases Information Center (GARD)

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Pulmonary sequestration


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Your Question

I have been diagnosed with intralobular pulmonary sequestration. What are the symptoms of this condition? How is it treated?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is pulmonary sequestration?

Pulmonary sequestration is a rare malformation where non-functioning lung tissue is separated from the rest of the lung and supplied with blood from an unusual source, often an artery from systemic circulation.[1][2] It may be congenital (present from birth) or acquired.[2] Pulmonary sequestrations may be defined as intralobular or extralobular, depending on their location.[2][3] Symptoms may include chronic cough, respiratory distress or infection. Treatment depends on the location and may involve surgery.[2]
Last updated: 4/6/2010

What is intralobular pulmonary sequestration?

Intralobar pulmonary sequestrations share a common visceral pleural investment with the adjacent normal lung tissue. The sequestered tissue, denied normal access to the tracheobronchial tree, is prone to infection, cyst formation, and bronchiectasis with scarring. While the intralobular pulmonary sequestration is usually not in communication with the tracheobronchial tree, it may contain air via the pores of Kohn or a connection to normal small bronchi. Most pulmonary sequestrations (75%) are intralobular. They occur more often on the left side and almost exclusively in the lower lobes; bilateral involvement is rare. Infections are common and diagnosis may occur in later childhood, adolescence or adulthood.[2][4] They are rarely associated with other anomalies.[2]
Last updated: 4/6/2010

What are the symptoms of intralobular pulmonary sequestration?

From mid-childhood onward, cough, purulent (pus) sputum (the phlegm you cough out of your lungs) production, and hemoptysis develop; a chest radiograph may reveal a solid or cystic lesion in the lower lobe, more often on the left side.[4] Patients with intralobular pulmonary sequestration can present with massive spontaneous hemorrhage, which is potentially fatal but exceedingly rare. Other complications and causes of morbidity include chronic infection and fibrosis. Intralobular pulmonary sequestration is not commonly associated with other congenital anomalies.[2]
Last updated: 4/6/2010

What causes intralobular pulmonary sequestration?

Intralobular pulmonary sequestration can be congenital or acquired.[2] Familial cases are known but rare.[4] Acquired forms are believed to be associated with a postinflammatory process; acquired after one or more episodes of necrotizing pneumonia which results in obliterative bronchitis and obstruction of a lower lobe bronchus. Congenital cases are likely explained by the accessory lung bud theory.[2] During bronchial branching (complete in humans 16 weeks after conception), the dividing buds are supplied by a capillary plexus derived from the primitive aorta; this plexus later regresses. Growth  arrest locally of the pulmonary artery during bronchial division may disrupt maturation and tracheobronchial integrity, as well as leading to persistence of the blood supply from the aorta.[4] 
Last updated: 4/6/2010

How might intralobular pulmonary sequestration be treated?

Due to the risk for infection and bleeding, intralobar pulmonary sequestrations are usually removed, either by segmentectomy (removal of part of the lung) or lobectomy (removal of the full lobe). Historically, angiography was considered an important preoperative study before embarking on resection of a sequestration. More recently, CT and MRI have replaced the need for angiography and provide excellent mapping of the blood supply.[3][5] 
Last updated: 4/6/2010

References
  • Pikwer A, Gyllstedt E, Lillo-Gil R, et al.. Scand J Surg. 2006; http://www.ncbi.nlm.nih.gov/pubmed/17066616. Accessed 4/6/2010.
  • Khan AN, Aird M, Chiphang A, et al.. Pulmonary Sequestration. eMedicine. 2008; http://emedicine.medscape.com/article/412554-overview. Accessed 4/6/2010.
  • Kliegman. Chapter 392 - Congenital Disorders of the Lung. In: Finder JD, Michelson PH. Nelson Textbook of Pediatrics, 18th ed.. Saunders; 2007;
  • Mason. Murray & Nadel's Textbook of Respiratory Medicine, 4th ed.. Saunders; 2005;
  • Townsend. Sabaston Textbook of Surgery, 18th ed.. Saunders; 2007;