Pulmonary sequestration

bronchopulmonary sequestration

1. BRONCHOPULMONARY SEQUESTRATION Dr Hammad ur Rehman PGR, PSW,SHL

2. During repair of congenital diaphragmatic hernia, you noticed a small lobular tissue which has a blood supply from thoracic aorta. What is your likely Diagnosis? How will you manage this?

3. Introduction Bronchopulmonary sequestration (BPS ) is a rare congenital abnormality of the lower respiratory tract. ` It consists of a non-functioning mass of lung tissue that lacks normal communication with tracheobronchial tree. It has arterial blood supply from systemic circulation.

4. Types Intra lobar Sequestration (ILS) Extra lobar Sequestration (ELS)

5. Intralobar Sequestration Most Common 75 % Located within the normal lobe and does not have its own visceral pleura. Males and females are equally affected. 15 % are associated with congenital anomalies(Skeletal anomalies) Most occur in lower lobes , 60% located in posterior basal segment of left lower lobe

6. The right lower lobe may be affected in approximately one- third of cases Generally do not have communication with tracheobronchial tree. Arterial blood supply is by lower thoracic aorta or upper Abdominal aorta Venous drainage is usually via the pulmonary veins on left side and IVC on right side . Intralobar sequestration usually present in late childhood or in young adults with recurrant attacks of pneumonia .

7. Within visceral pleura of normal lobe Arterial supply by thoracic aorta Venous drainage into Pulmonary veins

8. Extralobar Sequestration Less Common 25 % Located outside the normal lung and has its own visceral Pleura Male predominance. ELS are more common on the left side [ between the left lower lobe and hemi diaphragm (80%)]. They may also be found within or below the diaphragm or in retroperitoneum

9. 50% congenital anomalies associated (diaphragmatic hernia, cardiac, verterbral defects, hybrid forms CPAM/sequestration) Extralobar sequestration is typically supplied by a systemic artery arising directly from the THORACIC aorta . The vessel is usually small with low flow. Its venous drainage is usually through azygos-hemiazygos system . Most regress during 3 rd trimester of gestation. Symptoms with first six months .

10. Accessory lung tissue surrounded by its own pleura Arterial supply by thoracic aorta Venous drainage into systemic veins

11. Rare types Hybrid lesions :- BPS occurs in combination with CPAM. These hybrid lesions have histological features of CPAM and blood supply from a systemic artery. Bronchopulmonary -foregut malformation (BPFM)- A Rare variant of sequestration where sequestrated lung tissue is connected to the gastrointestinal tract .

12. Pathogenesis The most frequently supported theory of sequestration involves formation of accessory lung bud that develops from the ventral aspect of the primitive foregut. The pleuripotent tissue from this additional lung bud migrates in a caudal direction with the normally developing lung.

13. The accessory lung bud receives its blood supply from vessels that connect to the aorta and cover the primitive foregut . These attachments to the aorta remain to form the systemic arterial supply of the sequestration.

14. Early embryologic development of the accessory lung bud in pseudoglandular stage (5-17weeks of gestation) results in formation of the sequestration within normal lung tissue. This sequestration is encased within the same pleural covering of normal lung resulting in the Intrapulmonary or Intralobar sequestration.

15. Later development of the accessory lung bud results in the Extralobar OR Extrapulmonary type that may give rise to communication with the GI tract

16. Prenatal Evaluation   On prenatal ultrasound , BPS appears as homogenous echogenic thoracic mass usually solid appearing, triangular, located in lower hemithorax adjacent to the diaphragm . Detection by color Doppler of systematic artery from aorta is a pathogenomic feature of fetal BPS. If Doppler finding is not detected, CCAM and BPS have similar sonographic appearance.

17. Clinical Presentation The clinical features of BPS are variable and depends upon the type, size and location of the lesion. Most infants are asymptomatic at birth. If symptomatic, may present with respiratory distress at birth or in the neonatal period, usually due to large lesions that limit the volume of normal lung

18. The most common symptomatic presentation after neonatal period is with pulmonary infection , typically presenting as fever and cough, sometimes hemoptysis or chest pain, in pts. with ILS. Patients with ELS unlikely to develop infection. ELS may induce hydrops fetalis Rarely may present with heart failure due to excessive flow through aberrant artery.

19. Post Natal Evaluation Chest Radiograph: Sequestrations typically appear as a uniform dense mass within the thoracic cavity or lung parenchyma. R ecurrent infections in ILS can lead to cystic areas within the mass. Air-fluid levels in case of bronchial communication

20. Computed tomography (CT) Most common appearance is a solid mass that may be homogenous or heterogenous , sometimes with cystic changes. Less frequently, a large cavitary lesion with an air-fluid level. Emphysematous changes at the margin of the lesion.

21. MRI This is a safe and non-invasive alternative imaging method, which may be useful. MRI provides an excellent observation of the supplying systemic arterial anatomy. MR imaging can also depict the pulmonary venous return of the lesion and the relationship of the draining vein to the cardiac chambers.

22. Angiography Traditionally, Angiography has been considered as the gold standard for diagnosis of pulmonary sequestration by virtue of its excellent depiction of the arterial and venous anatomy Now it is replaced by multidetector CT or MRI angiograph.

23. Advanced imaging may help to distinguish among ILS, ELS and hybrid lesions. They are not completely reliable in making these distinctions. T he final definitive diagnosis is made only by PATHOLOGICAL EXAMINATION after surgical resection

24. Protocol For Evaluation Immediate advanced imaging with CT/MRI for pts with high risk : - Any symptoms (respiratory distress) - Large BPS ( >20% of lobe involved) - Bilateral or multifocal cysts, pneumothorax The purpose of the advanced imaging is to make the diagnosis and identify the aberrant artery and to help with surgical planning

25. Management Prenatal: Mojaority of BPS cause no fetal compromise and are best manage after birth. If Hydrops fetalis develop = treated with thoracoamniotic shunting followed by postnatal resection A blation of feeding vessel with contact laser.

26. Post Natal Management For Extralobar Sequestration: The postnatal treatment depends on the S ize of the lesion Blood flow P resence of a pleural effusion L ocation .

27. Indications for Resection of Extralobar BronchopulmonarySequestrations Large systemic vascular supply Large lesions with compression of surrounding lung parenchyma or mediastinal shift Lesions with cystic components on prenatal ultrasound or postnatal CT scan Lesions that continue to grow postnatally Lesions within or under the diaphragm

28. For small intrathoracic or subdiaphragmatic ELS There is debate regarding the postnatal management of a small intrathoracic or subdiaphragmatic eBPS . Small eBPSs with small feeding vessels have been reported to spontaneously regress and carry a low risk of infection or malignancy .

29. The surgical management of eBPSs involves Ligation and division of the systemic vasculature removal of the mass . This must be done with care as systemic vessels arising from the abdominal aorta may cross the diaphragm and lead to difficult-to-control bleeding if not adequately ligated Percutaneous coil embolization of the feeding systemic artery

30. For intralobar Sequestration All these lesions should be resected because of the risk of infection as well as the natural evolution of the high output physiology . The optimal age for resection is 8–10 weeks of life . Thoracoscopic lobectomy is a preferred approach.

31. SUMMARY Bronchopulmonary Sequestration is a rare congenital abnormality of lower respiratory tract. • It consists of a non-functioning mass of lung tissue that lacks normal communication with tracheobronchial tree and receives it blood supply from the systemic circulation. • An intralobar sequestration (ILS) is located within a normal lobe and lacks its own visceral pleura whereas An extralobar sequestration (ELS) is located outside the normal lung with its own visceral pleura

32. Clinical presentation depends on type, size and location of the lesion. • BPS can be detected by prenatal ultrasound & they may regress during gestation in most cases or may progress. • The affected newborn is usually asymptomatic, sometimes may present with respiratory distress. • On chest x-ray, typically appears as a uniformly dense mass within the pulmonary parenchyma. Recurrent infections can lead to cystic areas within the mass, and air-fluid levels if communicates with a bronchus.

33. Infants presenting with respiratory distress are treated with surgical excision. • For asymptomatic pts of any age with high risk for developing complications, surgical resection rather than observation. • Without high risk characteristics, conservative management with observation