congenital lung anomalies.pptx by dr payal gawai

congenital lung anomalies.pptx by dr payal gawai

1. Tracheal Agenesis absence of growth in the trachea or in part of it . male to female ratio is 2: 1 incompatible with life 3 anatomical patterns are recognized – Type 1 -agenesis of the proximal trachea, 20 % of cases. The distal trachea is present and is often connected to the oesophagus by a fistulous communication . Type 2 , -main bronchi join in the midline and communicate with the oesophagus by a single fistula, is the most common variety (60%) Type 3, in which the left and right main bronchi join the oesophagus independently , 20% of cases . Sometimes the trachea, though patent, is shortened congenital brevicollis or the ‘short neck syndrome ’- the absence of a number of cartilaginous rings, patent, and short trachea. most commonly associated with Klippel–Feil syndrome, and characterized by a triad of short neck, decreased neck mobility and low occipital hairline

2. Tracheo-oesophageal fistula The H-type tracheo-oesophageal fistula , in which both the trachea and oesophagus remain patent, may be sufficiently small to go undetected until adult life , despite the presence of recurrent symptoms from infancy . Aspiration of oesophageal contents into the airways may cause choking, with cough and cyanotic episodes after feeding. abdominal distension, Recurrent pneumonia Tracheo-oesophageal fistula may occur in partial tracheal agenesis and also in oesophageal atresia , typified by a blind proximal pouch and distal fistulous communication between the lower oesophagus and trachea .

3. Tracheal stenosis Tracheal stenosis is diffuse ( 30% ), the pars membranacea being absent so that the trachea is encircled by ‘napkin-ring’ cartilages, the total number of which may exceed the usual complement of 22. More most common (50% of cases) the stenoses are segmental and may occur with equal frequency in the upper, middle and lower parts of the trachea . In 20% of cases the stenosis is carrot or funnel-like associated with tracheo-oesophageal fistulae , association with Down’s syndrome in infancy with stridor and respiratory insufficiency. Surgical treatment may be necessary, and various plastic tracheal reconstruction procedures have been described.

4. Tracheal narrowing due to extrinsic Pressure Congenital tracheal narrowing due to extrinsic pressure generally results from the close proximity of unusually large or abnormally placed vessels that have arisen as the result of faulty development of the primitive system of branchial arches . double aortic arch (47 %), right aortic arch with left ligamentum arteriosum (20%), retrooesophageal right subclavian artery (14 %), anomalous innominate artery (11 %), anomalous left carotid artery (4 %), retrotracheal or ‘sling’ left pulmonary artery (3 %) and right aortic arch with aberrant left subclavian artery (1 %) requires surgical repair .

5. Tracheomalacia This term is used to indicate excessive weakness and collapsibility of the tracheal walls as a result of abnormally soft or pliable cartilages . It may occur in localized form as the result of a deficiency of cartilage in a short segment of trachea . Acquired forms of tracheomalacia - 1. prolonged endotracheal intubation and 2. relapsing polychondritis Tracheomalacia may be associated with other tracheooesophageal anomalies and presents in childhood with expiratory airflow obstruction and apnoeic episodes. surgical intervention with aortopexy and tracheal splinting .

6. Tracheobronchomegaly unusual width of the trachea and main bronchi and , because of the ineffectiveness of cough, often complicated by lower respiratory infection and bronchiectasis The cough may have a loud booming quality congenital inherited - autosomal recessive; Association with Ehlers– Danlos syndrome. MC seen in young adults but it has been found in children. There is an atrophic or congenital defect of the connective tissues of the trachea and main bronchi. tracheo-bronchogram and on CT or magnetic resonance imaging There is gross variation in diameter of the trachea with respiration and there may be other distortions and irregularities . structural or functional narrowing of the trachea may produce clinical features, including wheezy dyspnoea , respiratory distress during feeding, recurrent lower respiratorytract infection, stridor , tugging inspiratory effort with intercostal muscle retraction, cyanosis and Apnoeic episodes .

7. Bronchial atresia - Bronchial atresia : Rare congenital condition where a segment of bronchus is sealed off. - Affected segment : Typically the apicoposterior segmental bronchus of the left upper lobe. - Pathophysiology : Sealed-off bronchus forms a mucocele due to retained secretions. - Ventilation: Collateral ventilation through interalveolar pores, but impaired lung development in affected segment. - Clinical presentation : Often asymptomatic; may be incidentally found on imaging. - Imaging findings : Coin lesion on chest radiograph ; hyperlucency in distal lung due to air trapping. - Diagnostic tools: Bronchography shows non-filling of affected bronchus; CT confirms diagnosis. - Management: Surgical excision ( lobectomy or segmentectomy ) for symptomatic cases or diagnostic confirmation. - Complications: Rarely associated with lower respiratory tract infections; vascular abnormalities and pectus excavatum may coexist.

8. Bronchogenic cysts ( bronchial cysts) Developmental origin : Arises from abnormal budding of the tracheobronchial tree during intrauterine development, typically between the 26th day and 16th week of gestation. Classification : Bronchogenic cysts can be classified based on their location: Central ( Mediastinal ) : Detach early from major airways, often found near the trachea, carina, main bronchi, or adjacent to the esophagus. Peripheral ( Intraparenchymal , Intrapulmonary) : Arise later in development, situated towards the periphery of the lung. Commonly found in lower lobes, and can be single or occasionally multiple. Epidemiology : More common in males and reportedly more frequent among Yemenite Jews. Distribution : Peripheral bronchogenic cysts are at least as common as central ones. Approximately two-thirds of peripheral cysts are located in the lower lobes . Multiplicity : Typically solitary but can be multiple and occasionally present bilaterally. Rare occurrences : Bronchogenic cysts can also manifest in ectopic locations such as near the pericardium, diaphragm, vertebral column, or even within the skin .

9. Pathological features Size : Bronchogenic cysts can vary in size and may grow up to 10 cm in diameter. Histological features : They typically have thin walls that can thicken if infected. Internally, they are lined with ciliated respiratory epithelium and contain smooth muscle, elastic tissue, cartilaginous structures, and mucous glands. Diagnostic features : Presence of cartilage in their walls distinguishes them from cysts of other origins. Some cysts may have a fistulous connection with an adjacent airway, which can fill the cyst with air and potentially lead to enlargement. Fluid contents : Uninfected cysts contain clear fluid, but infection can alter their contents and destroy their characteristic histological features. Clinical implications : In some cases, a ball-valve mechanism can cause cyst enlargement, leading to symptoms that may present in infancy or, rarely, in young adulthood due to lung displacement. Complications : Chronic infection can make it challenging to distinguish between a chronically infected bronchogenic cyst and an acquired lung abscess. Additionally, there have been reported cases of bronchogenic cysts developing rhabdomyosarcoma , although this is rare.

10. Clinical features Asymptomatic presentation : Often discovered incidentally on chest radiographs ordered for unrelated reasons. Symptoms : When present, symptoms are typically due to: Mass effect : Pressure on adjacent structures such as the trachea, bronchi, heart, or esophagus. Infection : More common cause of symptoms. Symptoms from mass effect : Respiratory : Dyspnea , cough, stridor due to compression of the trachea or bronchi. Cardiac : Dysrhythmias due to compression on the heart. Esophageal : Dysphagia from compression on the esophagus. Complications : Recurrent infections : Due to bronchial compression leading to lower respiratory tract infections or atelectasis . Infection of cyst contents : Can lead to cyst enlargement and rupture. Rupture : May occur into the mediastinum or adjacent airway, resulting in symptoms such as cough with mucopurulent material or hemoptysis (coughing up blood).

11. Radiographic features Radiographic findings : Diagnosis is often suspected based on chest radiographs showing: A well-circumscribed, rounded, homogeneous opacity. Location can be in the mediastinum close to a major airway or in the periphery of the lung. If there's a fistulous communication, an air-fluid level may be visible, sometimes resembling a large emphysematous bulla. Presence of calcification in the cyst wall is variable and uncertain. Additional diagnostic tools : Barium swallow : Useful if the cyst is centrally located to demonstrate compression of the esophagus. CT scan : Provides detailed imaging to confirm the presence, size, location, and characteristics of the cyst, helping distinguish it from other mediastinal or pulmonary lesions.

12. Treatment Elective surgical resection : Generally recommended due to the difficulty in definitively diagnosing the cyst preoperatively and the potential for serious or life-threatening complications. Diagnostic uncertainty : It's often challenging to differentiate bronchogenic cysts from neoplastic conditions solely based on imaging or clinical findings. Complications : Bronchogenic cysts can lead to significant complications, reinforcing the rationale for surgical intervention. Management considerations : Asymptomatic small cysts : In some cases, particularly if the cyst is small and asymptomatic, or if surgery poses high risks due to patient factors, observation or needle aspiration may be considered. Risks of leaving cysts : Leaving cysts in situ carries a risk of potential complications such as infection, enlargement, or rupture. Surgical indication : Surgery is typically indicated to confirm the diagnosis, prevent complications, and ensure complete removal of the cyst

13. Congenital adenomatoid malformation of the lung Synonyms and historical names :Also known as congenital bronchiectasis or pulmonary cystic disease in older literature. Extent of involvement : CCAM can affect a portion of a lobe, an entire lobe, or in rare cases, an entire lung. Pathological features :The affected lobe or lung lacks a well-defined bronchial system. It contains disorganized pulmonary tissue with excess air passages resembling terminal bronchioles. Often includes mucous cysts of varying sizes. Variants : Accessory lung : In some cases, CCAM may involve a separate mass connected by an extra bronchus to the normal bronchial tree, resembling an accessory lung. Classification by Stocker et al. : Type I : Characterized by single or multiple large cysts, which are the most common form (50% of cases) and generally have a good prognosis. Type II : Involves multiple small cysts (<1 cm in diameter), accounting for 40% of cases, and typically carries a poorer prognosis than Type I. Type III : Represents a solid, airless mass of tissue, indicating a very poor prognosis. Clinical implications : Prognosis varies significantly depending on the type and extent of CCAM. Surgical management is often necessary to alleviate symptoms, prevent complications, and potentially improve outcomes, especially in cases with poor prognostic indicators like Type II and Type III

14. Developmental origin : CCAM is believed to result from a developmental anomaly where the proximal bronchial system, originating from the epithelial laryngotracheal bud, fails to properly unite with the distal alveolated tissue derived from mesoderm. Nature of anomaly : It represents a developmental anomaly affecting both the tracheobronchial tree and the lung parenchyma. Neonatal and fetal outcomes :Approximately 50% of cases involve premature births, and 25% are stillborn. Many infants born alive may die within hours due to complications such as anasarca (fluid accumulation), often caused by compression of the vena cava due to the space-occupying effect of the abnormal tissue mass. Post-neonatal complications :If the infant survives beyond the neonatal period, infection of the cysts commonly occurs, although symptoms may not manifest until 2 or 3 years later. Pneumothorax (collapsed lung) can complicate the condition due to air trapping in the cystic spaces. Antenatal diagnosis : Advances in prenatal ultrasound examination allow for the antenatal diagnosis of CCAM. This early detection enables planning for potential surgical intervention, such as resection of affected parts of the lung. Treatment : Surgical resection of the affected lung tissue is often considered feasible in cases where diagnosis occurs antenatally or early in infancy, aiming to prevent complications and improve outcomes

15. Anomalies involving the lung parenchyma Agenesis and hypoplasia of the lung: Terms "agenesis" and " hypoplasia " can be inconsistently used in literature. In this book: "Agenesis" = absence or almost complete absence of lung growth. " Hypoplasia " = underdeveloped lung with normal number of lobes, fewer bronchial branches, and alveoli. Complete bilateral lung agenesis is extremely rare and incompatible with life. Unilateral lung agenesis: Less rare, varies in severity. More common in the left lung. Often associated with other congenital abnormalities, such as patent ductus arteriosus . Forms of unilateral lung agenesis: Rudimentary bronchus with complete absence of lung tissue. Total absence of both lung and bronchial system. Rudimentary bronchial system with reduced alveolated tissue, classified as lung hypoplasia .

16. In many patients, the cause of lung hypoplasia is unknown. Conditions that decrease intrathoracic space, such as congenital diaphragmatic herniae , can cause unilateral lung hypoplasia . This can also be associated with ipsilateral congenital vascular anomalies Bilateral pulmonary hypoplasia is associated with: Oligohydramnios caused by renal tract disorders or amniotic fluid leak. Premature rupture of membranes. Impaired lung development detectable antenatally via ultrasonographic measurement of chest wall diameter. Maternal treatment with angiotensin -converting enzyme inhibitors during pregnancy.

17. genesis or hypoplasia of the lung is often associated with major extrapulmonary developmental abnormalities.Death frequently occurs in infancy in such cases. If the anomaly is confined to a lung or part of it:Prolonged survival is possible. Likely to have recurrent episodes of lower respiratory tract infections. Imperfect drainage of lung secretions or spillover from a blind bronchial stump may cause infections. Chest radiograph in lung agenesis or hypoplasia shows:Hemithorax of diminished volume. Crowded ribs. Elevated hemidiaphragm . Mediastinal displacement to the affected side. Overinflation of the contralateral lung, which may expand across the midline. These radiographic appearances resemble atelectasis . Bronchoscopy , CT, and occasionally pulmonary angiography may be needed to differentiate

18. Congenital abnormalities of lobulation - Complete agenesis of a lung lobe is rare. - Congenital anomalies of lobulation are more common. - A frequently encountered lobulation anomaly is the azygos lobe. - An azygos lobe is the medial portion of a bifurcated right upper lobe. - It is considered an anatomical variation in humans. - It is a constant feature in porpoises. - Formation: - Occurs during lung development if the enlarging apex of the right lung encounters the azygos vein. - Normally, the right upper lobe lies lateral to the azygos vein. - In this anomaly, the right upper lobe bifurcates, placing a portion of the lung on either side of the azygos vein. - The azygos vein creates an invagination in the right upper lobe, forming a supernumerary fissure. - This fissure is bounded by layers of visceral and parietal pleura. - On chest radiographs, it appears as a thin outwardly convex line ending in a small triangular shadow. - Bronchial anatomy remains intact. - The presence of an azygos lobe carries no morbidity. - Present in about 0.25% of chest radiographs. - Correct interpretation of its features is important. - A similar anomaly can very rarely occur in the left upper lobe.

19. Lung sequestration - **Lung sequestration**: - A spectrum of developmental pulmonary anomalies. - Characterized by the formation of an abnormal, unventilated lung tissue island. - This tissue has no normal communication with the bronchial system. - Derives its arterial supply from the systemic circulation, not the pulmonary circulation. - **Types of Lung Sequestration**: 1. ** Intralobar Sequestration** (more common): - Abnormal lung tissue is contained within the substance of normal lung tissue. - Completely surrounded by normal lung tissue. 2. ** Extralobar Sequestration** (rarer): - Abnormal lung tissue lies close to but outside the normal lung. - Situated outside the pleural coverings of the lung. - Invested by its own separate pleural membranes. - There are numerous variants and much overlap between intralobar and extralobar types.

20. Extralobar Sequestration : Entirely disconnected from normal lung. Referred to by some authors as an "accessory lung without a bronchial connection". Occurs four times more commonly in males than females. Gender Incidence : Intralobar sequestration: equal incidence in males and females. Extralobar sequestration: more common in males. Location : Both forms occur more commonly in the left hemithorax . Intralobar sequestration: 60% of cases on the left side. Extralobar sequestration: over 90% of cases on the left side. Left-Sided Propensity : Reasons are unclear. Possibly connected to the later closure of the primitive pleuroperitoneal canal on the left side during development. Absence of hepatic tissue on the left provides additional space for abnormal tissue development.

21. Diaphragmatic Defects : Common in extralobar sequestration (60% of cases). Rare in intralobar forms. Common Sites : Intralobar Sequestration : Most commonly in the posterior basal segment of either lower lobe. Rarely involves the upper lobe. Occasionally, an entire lung may be sequestrated. Extralobar Sequestration : Majority found between the left lower lobe and the diaphragm. Can also occur below the diaphragm, within the diaphragmatic substance, within the mediastinum , or as far cephalad as the neck. Vascular Supply : Reviewed by Thilenius and colleagues. Both types usually receive arterial supply from the descending aorta or its branches. Extralobar Sequestration : More common subdiaphragmatic supply. Vessel passes through the aortic or oesophageal hiatus or a separate diaphragmatic defect. Intralobar Sequestration : Arteries tend to be disproportionately large relative to the tissue volume. Supplying arteries may be multiple in both types. Venous Drainage : Intralobar Sequestration : Drains into the pulmonary venous circulation. Extralobar Sequestration : Drains by the azygos system of veins. Large shunts can result, leading to early life heart failure in some patients.

22. Extralobar Sequestration : About 50% of patients have other congenital abnormalities. These abnormalities are often severe enough to bring medical attention. Diagnosed in the first year of life in up to 60% of patients. Intralobar Sequestration : Widespread congenital abnormalities are rare. Diagnosis seldom made in neonatal life. Over 50% of cases are diagnosed after the age of 20. Comparison of Features : A table (Table 50.1) is provided to compare features of intralobar and extralobar sequestration.

23. Aetiology No single theory of causation is entirely acceptable due to the need to explain both intralobar and extralobar sequestration and their variants. Theories of Causation : Occasional reports of both intralobar and extralobar sequestration in the same patient support a unitary theory. One proposition is that pulmonary sequestration develops from an accessory lung bud distal to the normal laryngotracheal bud on the ventral aspect of the primitive foregut. Development Process : Anomalous bronchial tissue grows and becomes invested by primitive respiratory mesenchyme . The amount of mesenchyme determines the size of the sequestration and the development of its respiratory bronchioles and alveolar tissue. The original foregut connection may involute and disappear, possibly due to outgrowth of its blood supply. Occasionally, a foregut communication persists, especially in extralobar forms. Intralobar vs. Extralobar Sequestrations : Accessory buds near the laryngotracheal bud may become incorporated into it during development, resulting in intralobar sequestrations. Accessory buds arising more distally from the foregut (either from the esophagus or proximal stomach) escape envelopment, resulting in extralobar sequestrations. Both types typically retain their primitive systemic arterial supply. Venous drainage varies: Intralobar Sequestration : Drains into the pulmonary system if developed close to the laryngotracheal bud. Extralobar Sequestration : Drains into the systemic system if developed more distally.

24. Pathology Intralobar Pulmonary Sequestration : Macroscopically appears as a well-circumscribed reddish-grey area. Clearly differentiated from healthy lung but intimately related to it. Typically situated within the posterior basal segment of either lower lobe. Extralobar Pulmonary Sequestration : Separated from normal lung. Surface is shiny and homogeneous, covered by its own pleural investment. Vascular Supply : Both forms typically receive a systemic arterial supply. Usually derived from the aorta. Vessels have the elastic structure of a pulmonary artery rather than the muscular structure of a normal aortic branch. Histological Features : Both intralobar and extralobar sequestrations typically contain: Dilated ciliated bronchi. Focal development of alveolated tissue. Bronchial dilatation by retained secretions and edema may form cysts visible to the naked eye. Usual histological features may be lost if the sequestration becomes infected.

25. Diagnosis in First Year of Life : Often discovered during investigation of multiple congenital abnormalities. Usually extralobar in type. Diagnosis in Adult Life : Sometimes found in asymptomatic individuals during routine chest radiographs. May present with non-specific symptoms of lower respiratory tract infection or recurrent pneumonia. Symptoms include cough, sputum production, and occasionally massive hemoptysis . Complications : Sequestrated segments can become distended by mucous secretions. Lack of foregut communication prevents drainage, compressing surrounding normal lung tissue and leading to infection. Infection can lead to the development of a fistula between the sequestrated segment and surrounding lung, resulting in persistent infection due to inadequate drainage. Extralobar sequestrations may be less prone to infection as they are entirely separate from normal lung. Clinical Features : Signs of pneumonic consolidation may be present. Features of pleurisy and pleural effusion are unusual. Finger clubbing and associated bony deformities of the ribs and chest wall have been described.

26. Radiographic Features : Intralobar Sequestration : Suspected with a persistent opacity in either of the posterior basal segments. Non-aerated tissue in the sequestration may produce a homogeneous shadow. Margins may be ill-defined, appearing as a solitary pulmonary nodule. Cystic changes may be visible, with cysts containing air-fluid levels, indicating a fistulous bronchial communication or collateral ventilation at the alveolar level. Extralobar Sequestration : Less easily seen. May appear as a small opacity contiguous with the left hemidiaphragmatic shadow. Persistent foregut connections can sometimes be demonstrated by barium swallow. Diagnostic Imaging : Bronchography : Shows non- opacification of the sequestration. Sequestration seen to be surrounded by normally ramifying bronchial branches. CT and Retrograde Thoracic Aortography : Confirm diagnosis. Demonstrate feeding arteries, usually from the descending aorta just above or below the diaphragm. Important to exclude other possibilities (e.g., pneumonia, bronchiectasis , lung abscess, and tumor) and forewarn thoracic surgeons of aberrant arteries. These diagnostic imaging techniques help in the identification and differentiation of pulmonary sequestration from other conditions.

27. Surgical Considerations : Identifying and ligating vessels is crucial during thoracotomy . Resection of symptomatic pulmonary sequestration is indicated. Preoperative Management : Treat any present infection with appropriate antibiotics. Surgical Procedures : Intralobar Sequestration : Usually requires segmental resection or lobectomy . Extralobar Sequestration : May be resected without disturbing normal lung tissue. Complications : Failure to properly identify aberrant vascular supply can result in disastrous bleeding. Bleeding has also been described as a complication of unresected sequestration.

28. Anomalies of the pulmonary vasculature Embryology of Pulmonary Vasculature : Intrapulmonary Vasculature : Derived from the mesenchymal investment of the primitive lung bud. Initially receives arterial supply from paired segmental arteries arising from the aorta. Pulmonary Vascular Plexus : Later joined by ramifications of the pulmonary arteries, derived from the sixth branchial arch. As the aorta migrates caudally, segmental aortic arteries involute and are replaced by bronchial arteries from the aorta at thoracic level. Venous Development : Initially drains into the primitive anterior and posterior cardinal veins. Later replaced when pulmonary veins from each lung fuse with a single large pulmonary vein from the sinus venosus . This structure is absorbed into the atrium, resulting in four pulmonary veins entering the left atrium separately. Pulmonary Vasculature Growth : Well developed by the 16th week of intrauterine life. Growth and vascular remodeling continue in utero . Disturbances in remodeling can lead to conditions like persistent pulmonary hypertension of the newborn. Persistent Pulmonary Hypertension of the Newborn : Associated with excessive muscularization of the intra- acinar arteries. One case linked to maternal aspirin ingestion during pregnancy. Hypothesized that pulmonary hypertension resulted from premature closure of the ductus arteriosus due to prostaglandin-inhibiting effects of aspirin.

29. Absent pulmonary artery trunk Absence of Pulmonary Artery Trunk : Can result from agenesis of the primitive sixth branchial arch. Can also result from developmental failure of the septum dividing the truncus arteriosus into the aorta and pulmonary artery trunk. Complications and Survival : A left-to-right shunt exists in these cases. Lungs are supplied by bronchial or other aberrant systemic vessels. Prolonged survival is impossible without major corrective surgery.

30. Absent unilateral pulmonary artery Definition : Absence of one or the other main pulmonary artery due to failure of the left or right primitive sixth branchial arch development in the embryo. Blood Supply : Affected side receives blood supply systemically, mainly from enlarged bronchial vessels or occasionally from aberrant arteries. Sources of Aberrant Arteries : Descending aorta, ascending aorta, aortic arch, left innominate artery, left subclavian artery, their branches, or a persistent right-sided ductus arteriosus . Frequency : Left and right pulmonary arteries are equally affected, but right-sided lesion more common in adults due to higher early mortality associated with left-sided lesion and congenital heart disease. Association with Congenital Heart Disease : 40% of cases with absent left pulmonary artery have Fallot’s tetralogy . Right pulmonary artery absence has no strong association with congenital heart disease. Lung Condition : Affected lung often hypoplastic with cystic and bronchiectatic changes. Pulmonary Hypertension : 20% of patients with right-sided absent pulmonary artery have pulmonary hypertension. Presentation : Infants: Often present with associated cardiac disease. Adults: May be asymptomatic, diagnosis often incidental via chest radiograph. Chest Radiograph Findings : Small hilar shadow and small hyperlucent lung on the affected side. Diagnosis Confirmation : Perfusion lung scan or pulmonary angiogram showing complete lack of perfusion on the affected side. Treatment : Usually not possible, but reconstructive anastomotic surgery and recanalization procedures may be considered. Pneumonectomy might be required for haemoptysis control, with thoracic aortography to demonstrate collateral circulation.

31. Pulmonary artery stenosis Postvalvular Pulmonary Artery Stenosis (Pulmonary Artery Coarctation ) Definition : A rare condition where stenosis occurs at any level from above the valve to the segmental arteries and beyond. Locations : Centrally placed stenoses (pulmonary artery trunk or left/right main pulmonary artery branches) are less common. Multiple peripheral lesions are more common and may be associated with pulmonary hypertension. Association with Other Conditions : More commonly detected alongside congenital heart disease. Described as part of rubella syndrome and idiopathic hypercalcaemia . Chest Radiography : May show poststenotic dilatations creating a beaded appearance contiguous with lung vascular markings. Poststenotic dilatations may occasionally become aneurysmal and rupture, causing haemoptysis . Diagnosis : Confirmed by pulmonary angiography. Treatment : Large centrally placed lesions may be corrected with surgery, but this carries a risk of massive intrapulmonary bleeding due to the rupture of distally placed hypoplastic pulmonary vessels.

32. Anomalous Left Pulmonary Artery (Pulmonary Sling Syndrome) Anomalous Left Pulmonary Artery (Pulmonary Sling Syndrome) Cause : Failure of the pulmonary arterial plexus of the left lung and the left part of the sixth primitive branchial arch to connect normally. Anomaly : The left pulmonary artery arises from the right pulmonary artery, looping around the right main bronchus and crossing the midline to enter the left hilum . Pathway : The aberrant artery runs between the lower end of the trachea ( anteriorly ) and the oesophagus ( posteriorly ). Syndrome : Known as "sling" pulmonary artery syndrome. Symptoms : Obstruction to the left main bronchus, trachea, and oesophagus , leading to dyspnoea (difficulty breathing) and dysphagia (difficulty swallowing). Associated Defect : May include an intrinsic tracheal defect where the pars membranacea is absent, and the trachea is encircled by "napkin-ring" cartilages. Imaging : Lateral Chest Radiograph : Shows a rounded opacity between the air-filled trachea and oesophagus at the level of the carina. Barium Swallow : May provide supportive evidence. Pulmonary Angiography : Confirms the diagnosis.

33. Anomalous systemic pulmonary perfusion Blood Supply : Dysplastic lung tissue can receive blood from systemic vessels other than the normal bronchial arteries, similar to pulmonary sequestration. Occurrence : Can occur without sequestration, with supplied lung tissue appearing normal. Origin of Abnormal Arteries : Typically from the descending thoracic aorta. May also originate from the ascending aorta, aortic arch, innominate , subclavian , internal mammary, intercostal arteries, abdominal aorta, or coeliac artery. Structure : These arteries have an elastic structure similar to pulmonary arteries, not the muscular form typical of aortic branches. Circulation : May communicate with the pulmonary circulation or drain systemically, potentially creating a left-to-right shunt. Symptoms : Often asymptomatic but can present with recurrent haemoptysis . Clinical Signs : An asystolic or continuous bruit with systolic accentuation may be heard over the involved chest area. Imaging : Chest Radiograph : May be normal or show increased irregular vascular markings near the anomalous vessels. Pulmonary Angiography : Typically shows no abnormality. Aortography : Diagnostic for these anomalies. Treatment : Surgical ligation or clipping of anomalous vessels. Therapeutic embolism. Occasionally, resection of the lung may be necessary to control haemoptysis .

34. Scimitar syndrome Scimitar Syndrome (Congenital Pulmonary Venolobar Syndrome) Definition : Also known as congenital pulmonary venolobar syndrome and vena cava bronchovascular syndrome. Key Feature : Drainage of part of the right lung by an anomalous, scimitar-shaped pulmonary vein, which passes through the lung parallel to but separate from the mediastinal structures before joining the inferior vena cava, typically below the diaphragm. Variable Features : Anomalous Systemic Arterial Supply : Multiple small arteries from the descending aorta, often below the diaphragm. These arteries enter the base of the right lung. The right main pulmonary artery is frequently small or absent. Hypoplasia of the Right Lung : The right lung is small and has fewer airways. May exhibit bronchial isomerism. Cardiac Dextroposition : The heart is displaced to the right side due to the small right lung. Diaphragmatic Abnormalities : The right hemidiaphragm may have an accessory leaf. This accessory leaf is fused anteriorly but separated posteriorly , containing lung tissue between its layers.

35. Inheritance : May occur in a familial pattern with autosomal dominant inheritance. Shunt : The left-to-right shunt typically does not produce significant ill effects. Most commonly diagnosed in asymptomatic adults during routine chest radiographs. Chest Radiograph Features : Characteristic curvilinear vascular density in the right lower lung (scimitar-shaped). Ipsilateral loss of lung volume, evidenced by mediastinal shift to the right and an elevated diaphragm. Imaging : Detailed imaging can be obtained through CT and pulmonary angiography. Plain radiographs are usually sufficient for diagnosis. Treatment : Surgical intervention is rarely necessary.

36. . Scimitar syndrome. (a) Postnatal frontal chest radiograph shows volume loss in the right hemithorax with rightward mediastinal shift. The right heart border is not well seen. An anomalous vessel (arrowheads) is seen in the right cardiophrenic angle. This vessel increases in caliber in the caudal direction (“scimitar sign,” so called because of its resemblance to a Turkish sword). (b) Coronal contrast-enhanced CT scan shows the lower lobe pulmonary vein (scimitar vein) draining into the intrahepatic inferior vena cava (arrows). (c) Volume-rendered CT image clearly depicts the anomalous vein (arrow)

37. Anomalous Pulmonary Venous Drainage Right Lung Drainage : Into the superior vena cava. Into the azygos vein. Into the right innominate vein. Left Lung Drainage : Into a left-sided superior vena cava or vertical vein, representing persistence of the embryonic left anterior cardinal vein. This vessel may: Drain cephalically to join the left innominate vein. Drain caudally to join the coronary sinus. Coronary Sinus Drainage : Pulmonary veins drain into the coronary sinus attached to the right atrium. Cor Triatriatum : A common single pulmonary vein drains into the right atrium through an additional atrium-like chamber, known as a cor triatriatum deformity.

38. Pulmonary arteriovenous malformations and telangiectasia Nature : Developmental anomalies with persistent vascular communications between arteries and veins within the lung, bypassing parts of the normal pulmonary capillary bed. Misclassification : Sometimes categorized as tumors, but contain no neoplastic cells. Incidence : Rare, with approximately three cases per year recorded at a major North American referral center over a 20-year period. Le Roux reported less than one case per year at a European thoracic surgical center compared to around 300 cases of bronchial carcinoma and 13 bronchial adenomas in the same period. Origin : Likely originate during the development of the primitive pulmonary vascular plexus, with an anastomotic vessel providing lower resistance to blood flow than the surrounding pulmonary vascular bed. Pathophysiology : Arterial blood is diverted through the path of least resistance, leading to gradual dilatation and enlargement of the anastomotic vessel, feeding arteries, and tributary veins. Veins draining the fistulous communication become distended and varicose. Size and Structure : The size of the lesion varies from very small to large labyrinthine masses of dilated, interconnecting thin-walled vascular spaces of lobar proportions. Physical Principles : The flow and enlargement are governed by haemodynamic factors.

39. Blood Supply and Drainage : 95% derive blood from branches of the pulmonary artery and drain into the pulmonary venous circulation. Remaining cases have systemic origins (aorta, innominate , subclavian , internal mammary, bronchial, and intercostal arteries) and may drain via systemic or pulmonary veins. Pulmonary Telangiectasis : Results from fistulous communication between small peripheral arterioles and venules . Diffusely distributed defects lead to a condition called pulmonary telangiectasia . Association with Hereditary Haemorrhagic Telangiectasia (HHT) : Also known as Osler– Rendu –Weber syndrome. Autosomal dominant condition found in 50–60% of PAVM cases. Only 5–15% of HHT patients develop PAVMs. Gene located on chromosome 9q3 is strongly associated with both conditions. Demographics : Slightly more common in women than men. Majority are single lesions, but 20–30% are multiple, more common in HHT patients. Approximately 10% occur bilaterally. Location and Frequency : Often located close to the visceral pleura. 70% occur in the lower lobes. Associated Anomalies : Vascular anomalies may also be present in other organs.

40. Age of Diagnosis : Typically diagnosed after the third decade of life. Hereditary haemorrhagic telangiectasia (HHT) usually manifests at puberty or later. Mean age at diagnosis for PAVMs is 40 years. Occasionally detected in infancy, especially in HHT patients. Asymptomatic Cases : More than half of patients have no symptoms at diagnosis. Often discovered during routine chest radiographs or HHT investigations. HHT Characteristics : Small, raised, red telangiectatic lesions (2–3 mm) on skin and mucosal surfaces. Lesions blanch on pressure, common around the face, lips, mouth, and nasopharynx . Mucosal lesions tend to bleed, leading to epistaxis , gastrointestinal bleeding, or symptoms of anemia. Respiratory Symptoms : Most common symptom is dyspnoea . Haemoptysis occurs less frequently. Physical Examination : A bruit is audible over the lesion site in over half of PAVM patients, typically systolic or continuous with systolic and inspiratory accentuation. Cyanosis may occur due to right-to-left shunting, often accompanied by finger clubbing. Symptom Likelihood : Unlikely in single discrete lesions with a radiographic diameter less than 2 cm. Multiple lesions do not necessarily increase symptom frequency, except in cases of numerous tiny lesions as seen in pulmonary telangiectasia syndrome, where symptoms are evident from childhood.

41. Haemorrhage : Most common complication. Can occur into the bronchial tree causing haemoptysis . Rarely into the pleural cavity causing haemothorax . Exceptionally, pneumothorax may occur. Neurological Complications : Transient Cerebral Ischaemic Attacks or Cerebral Infarction : Caused by systemic arterial hypoxaemia and secondary polycythaemia . Up to 50% of patients in some series have episodes suggestive of paradoxical embolization . Cerebrovascular Accidents : Due to rupture of associated intracranial arteriovenous malformations. From an embolus within or passing through a pulmonary arteriovenous malformation. Infections : Bacterial Endangiitis : May occur with a PAVM, leading to metastatic abscesses in the brain or other sites. Cerebral Abscesses : Can occur if infected material bypasses pulmonary capillary filtration through a PAVM.

42. Chest Radiograph : Appearance: Rounded, lobulated , or tortuous opacities. Often seen in the periphery of the lower lung fields. Feeding or draining vessels may be visible linking the malformation to the hilum . Shadows can mimic metastatic tumors due to their well-defined nature. Serial radiographs may show gradual enlargement over time. Size variation with intrathoracic pressure changes (e.g., Müller and Valsalva maneuvers). CT Scan : Useful for identification and delineation of lesions. Helps in assessing detailed morphology. Vascular calcifications are uncommon. Pulmonary Angiography : Gold standard for confirming diagnosis, especially in bilateral cases. Important before surgical consideration to identify small lesions not visible on plain radiographs. In cases with arterial supply from systemic vessels, aortography may be necessary for adequate demonstration. Pulmonary Telangiectasia : Radiographic Appearance: Diffuse nodularity , particularly in lower lung zones. Can mimic pulmonary fibrosis, potentially increasing over time. Small vascular lesions typically not visible on pulmonary angiography.

43. Shunting and Hypoxemia : Shunt Direction : Majority cause a right-to-left shunt, except those with systemic arterial supply. Effects : Can lead to arterial hypoxemia if the shunt is significant. Characteristics : Typically mild hypoxemia with normal or reduced Pco2; Sao2 remains reduced despite administration of pure oxygen. Quantification of Shunt : Measurement : Size of intrapulmonary shunt can be quantified as a percentage of cardiac output. Technique : Measured by comparing mixed venous and arterial oxygen content during 100% oxygen breathing for 20 minutes. Limitations : Dye dilution curves are ineffective due to proximity of fistulae to capillary level. Alternative Method : Radioactively labelled albumin macroaggregates injected into a peripheral vein: Normally trapped in pulmonary capillaries but pass through telangiectatic vessels in pulmonary telangiectasia . Shunt size estimated by radioactivity count over lungs, brain, and kidneys.

44. Pulmonary and Right Heart Pressures : Findings : Recorded as normal in a series of 22 patients. Exception : Pulmonary hypertension reported in a few cases, mechanism uncertain. Diffusing Capacity using Carbon Monoxide ( Dlco ) : Measurement : Used to assess gas exchange efficiency. Correction : Requires adjustment for hemoglobin levels in cases of polycythemia or anemia. Findings in Pulmonary Telangiectasia : Dlco may be reduced due to diminished pulmonary capillary blood volume

45. Indications for Active Treatment : Lesions with feeding vessels > 3mm diameter should be actively treated. Screening of relatives of patients with hereditary hemorrhagic telangiectasia (HHT) recommended to detect and treat asymptomatic lung lesions. Surgical Treatment : Solitary PAVM : Consider surgical removal after full evaluation. Peripheral PAVMs : Local resection with ligation of vessels. Deeper or extensive PAVMs : Wedge resection, segmental resection, or lobectomy to conserve lung tissue. Embolization Techniques : Indications : Multiple or bilateral PAVMs. Methods : Balloons or steel coils used to occlude feeding vessels distally. Advantages : Less invasive than surgery, avoids extensive or repeated procedures. Complications : Occur in around 10% of cases, including embolus displacement and myocardial puncture. Outcomes : Increased Pao2, improved exercise tolerance; recanalization is infrequent. Lung Transplantation : Considered in cases of multiple lesions or telangiectasia with significant cyanosis.

46. THANK YOU!