|Year : 2015 | Volume
| Issue : 6 | Page : 781-784
Isolated right pulmonary artery agenesis with aplasia of right upper lobe and with anomalous arterial supply from celiac axis, anomalous venous drainage
Tushar Madhav Kalekar1, Vilas M Kulkarni1, Tejasvi Thamatam2
1 Department of Radiodiagnosis, D.Y. Patil Medical College and Hospital, Pune, Maharashtra, India
2 Department of Radiodiagnosis, Radiolofy Resident, KEM Hospital, Pune, Maharashtra, India
|Date of Web Publication||19-Nov-2015|
Tushar Madhav Kalekar
Department of Radiodiagnosis, D.Y. Patil Medical College and Hospital, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
Pulmonary artery agenesis is the complete absence of the right or left pulmonary artery. This lesion is commonly associated with other cardiac anomalies and is usually diagnosed incidentally. Unilateral absence of pulmonary artery with lung hypoplasia is very rare. Ipsilateral hypoplastic or absent central pulmonary artery in these patients will have a systemic arterial supply to peripheral pulmonary arteries of the affected lung from the descending thoracic or upper abdominal aorta. These findings are usually characterized as pulmonary veno lobar syndrome or scimitar syndrome when associated with ipsilateral total or partial anomalous pulmonary venous return from the lower lobe which drains into the inferior vena cava or less commonly to the hepatic, azygous, or portal vein, or into the right atrium and lung agenesis/hypoplasia.
Keywords: Anomalous vascular supply, aplasia of lung, pulmonary artery agenesis
|How to cite this article:|
Kalekar TM, Kulkarni VM, Thamatam T. Isolated right pulmonary artery agenesis with aplasia of right upper lobe and with anomalous arterial supply from celiac axis, anomalous venous drainage. Med J DY Patil Univ 2015;8:781-4
| Introduction|| |
Unilateral absence of pulmonary artery (UAPA) is a rare congenital anomaly with estimated prevalence of around 1 in 200,000 individuals.  It may occur as an isolated lesion or in combination with cardiac or vascular lesions. About 75% of the patients with left-sided pulmonary artery agenesis have associated congenital cardiac anomalies. In comparison, occurrences of associated congenital cardiac anomalies are rarely seen in patients with right-sided pulmonary artery agenesis. The most frequent accompanying cardiovascular anomalies include tetralogy of fallot or septal defects. Other congenital cardiac defects associated with UAPA are coarctation of the aorta, subvalvular aortic stenosis, transposition of the great arteries, patent ductus arteriosus, congenitally corrected transposition, pulmonary stenosis, and scimitar syndrome. Although some patients with isolated UAPA are completely asymptomatic, others may have severe pulmonary hypertension and congestive heart failure. UAPA with lung hypoplasia is very rare. Only few cases of unilateral pulmonary artery agenesis have been reported from India. We report the case of a patient with right pulmonary artery agenesis with agenesis of the right upper lobe, the arterial supply of the right lung by a branch from the celiac axis.
| Case Report|| |
A full term baby who was delivered by normal vaginal delivery with birth weight 3.4 kg. On examination baby had ambiguous genetalia-bilateral empty scrotum, hyperpigmented labio scrotal folds and median raphe. Baby was presented with dyspnea and fever at the age of 3 weeks and managed underventilation. Total blood count was within normal limits. Serum electrolytes were in normal ranges. Renal function tests were also within normal limits. Liver function tests showed serum bilirubin -7.8 mg% (direct-0.6 mg %). Chest radiograph (posteroanterior view) showed [Figure 1] homogenous opacification of right hemithorax with an ipsilateral shift of the mediastinum, downward displacement of right hemidiaphragm. Ultrasonography of thorax did not reveal pleural effusion. Ultrasonography of abdomen showed the presence of the uterus, so the baby was likely to be female with the hypertrophic clitoris. No hepato-splenomegaly was noted. 2D echo showed absent right pulmonary artery, partial pulmonary venous drainage of right side pulmonary veins into inferior vena cava (IVC) and severe pulmonary hypertension. High resolution computed tomography (CT) of the thorax was suggestive of agenesis of the right upper lobe [Figure 2] with absent bronchus with an ipsilateral shift of the mediastinum. Hyperinflation of the right middle and lower lobe was noted. Patchy ground glass opacities and focal consolidations were seen in the right lower lobe [Figure 3], left lower lobe and left upper lobe. CT angiography of the chest revealed a complete absence of the right main pulmonary artery [Figure 4]. Anomalous systemic arterial supply from the aorta-coeliac axis to the right lower lobe [Figure 5]. Anomalous venous drainage seen from the right lower lobe into the azygos vein and hepatic portion of IVC [Figure 6]. Volume rendered reconstructed image confirmed anomalous arterial supply [Figure 7].
|Figure 1: Chest radiograph posterior-anterior view showing homogenous opacifi cation of right hemithorax with ipsilateral shift of the mediastinum, down ward displacement of right hemidiaphragm|
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|Figure 2: High resolution computer tomography coronal section showing agenesis of right upper lobe with ipsilateral shift of mediastinum and patchy consolidations in left lower zone|
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|Figure 3: High resolution computer tomography coronal section showing right middle and lower lobar bronchi with hyperinflation of right middle and lower lobes. Patchy ground glass opacities and focal consolidations are seen in right lower lobe, left lower lobe and left upper lobe|
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|Figure 4: Computed tomography angiography axial section shows left pulmonary artery and agenesis of right main pulmonary artery|
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|Figure 5: Computed tomography angiography shows anomalous systemic arterial supply from the aorta-coeliac axis to the right lower lobe|
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|Figure 6: Computed tomography angiography shows anomalous venous drainage seen from the right lower lobe into the hepatic portion of inferior vena cava|
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|Figure 7: Volume rendered reconstructed image showing anomalous arterial supply|
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| Discussion|| |
Approximately 1 in 15,000 children are born with congenital absence of one lung and the associated bronchus.  Unilateral pulmonary agenesis is the absence of the carina and the trachea running directly into a single bronchus. Unilateral pulmonary agenesis most likely results from an in-utero insult during the 4 th week of gestation.  Pathologically, the sole lung is larger than normal, this enlargement is true hyperinflation and not emphysema. The mortality of right-sided agenesis is twice that of left-sided agenesis; this is probably a result of more severe mediastinal and cardiac displacement. Concomitant anomalies are frequently found (>50% of affected fetuses) including congenital heart disease, vertebral abnormalities, imperforate anus, renal agenesis, and trachea-esophageal fistula.  There may be an association with duplications of chromosome 2. Lobar agenesis and aplasia are rarer than the complete absence of one lung and usually affect the right upper and middle lobes together. 
Unilateral pulmonary artery agenesis as an isolated phenomenon is even rarer, and patients affected are asymptomatic or present with symptoms that are either nonspecific or are discovered upon investigation after the discovery of an abnormal chest roentgenogram. In this subset of patients, the right lung is predominantly affected and patients usually present in early adulthood, although some present as late as the fifth or sixth decade of life. ,
Our patient had unilateral lobar agenesis, unilateral pulmonary artery and abnormal pulmonary venous drainage and systemic arterial supply, which fits into the spectrum of the congenital pulmonary venolobar syndrome (scimitar syndrome).
Scimitar syndrome is a rare association of congenital cardiopulmonary anomalies consisting of a partial anomalous pulmonary venous connection of the right lung to the IVC, right lung hypoplasia (these two are the most constantly occurring components), dextroposition of the heart, and anomalous systemic arterial supply to the right lung. The age at detection of scimitar syndrome and the presence of associated anomalies is important in predicting the outcome. In general, infants presenting in heart failure have a greater number of associated anomalies, and their prognosis is much worse. 
Differential diagnoses include Swyer-James syndrome, lobar atelectasis and chronic pulmonary thromboembolism. A contrast enhanced CT of the thorax confirms the absence of the affected pulmonary artery. Magnetic resonance imaging is helpful to evaluate the congenital cardiovascular defects. Ventilation-perfusion scan shows decreased ventilation and absent perfusion on the affected side. Absent perfusion on one side with bilateral normal ventilation may occur in the unilateral absence of a pulmonary artery, thrombotic occlusion of a main pulmonary artery or pulmonary arterial branch stenosis. These three conditions can be further differentiated by clinical history, physical examination or angiographic tudies. 
Echocardiography is a useful tool for exclusion/evaluation of other cardiac or major vessels abnormalities and the presence of associated pulmonary hypertension. Pulmonary angiography remains the gold standard for the diagnosis of pulmonary artery agenesis and is reserved for patients requiring embolization or revascularization surgery. ,
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7]