http:// ijp.mums.ac.ir Review Article (Pages: 10611-10620) Scimitar Syndrome: Pathology, Clinical Presentation, Radiographic Features, and Treatment *Yazdan Ghandi1, Alireza Farsi21 1Associate Professor, Pediatric Cardiologist, Amirkabir Hospital, Arak University of Medical Sciences, Arak, Iran. 2 Medical Student, Amirkabir Hospital, School of Medicine, Arak University of Medical Sciences, Arak, Iran. Abstract Scimitar syndrome is characterized by partial or total anomalous pulmonary venous return from the right lung along with pulmonary hypoplasia. We searched the mail databases such as Medline (via PubMed), Scopus and EMBASE and Google Scholar. Diagnosing infantile scimitar syndrome requires meticulous attention and high suspicion of the early referral and management. The association of the syndrome with pulmonary hypertension leads to recurrent and prolonged hospitalization. Scimitar syndrome can be initially suspected from a chest X-ray, but it is typically confirmed via Computed Tomography (CT) angiography. The clinical spectrum of Scimitar syndrome ranges from severely ill infants to asymptomatic adults, which may present respiratory or cardiac failure, hemoptysis and pulmonary hypertension, tachypnea, chest infection, and failure to thrive. The diagnosis can be made by transthoracic or transesophageal echocardiography, angiography, or by CT or MR angiography. Considering the wide clinical spectrum of scimitar syndrome, the medical intervention depends on the severity of presentation and the amount of blood flowing to the Inferior Vena Cava (IVC) from completely or partially anomalous pulmonary veins. In the presence of significant left to right shunting and pulmonary hypertension, surgical intervention should be considered. Key Words: Congenital Anomaly, Pulmonary Hypertension, Scimitar Syndrome. *Please cite this article as: Ghandi Y, Farsi A. Scimitar Syndrome: Pathology, Clinical Presentation, Radiographic Features, and Treatment. Int J Pediatr 2019; 7(12): 10611-620. DOI: 10.22038/ijp.2019.43898.3648 *Corresponding Author: Yazdan Ghandi (M.D), Pediatric Cardiologist, Amirkabir Hospital, Arak University of Medical Sciences, Arak, Iran. Zip code: 3817996647, Tel: +98 9378344116 Email: [email protected] Received date: Apr.20, 2019; Accepted date: Nov.22, 2019 Int J Pediatr, Vol.7, N.12, Serial No.72, Dec. 2019 10611 Scimitar Syndrome 1- INTRODUCTION (Pathology OR Clinical Presentation OR Radiographic OR Features OR Treatment). Scimitar syndrome was first reported Database search was done for possible by Naill et al. in 1960, as the radiographic appearance of the anomalous vein, which studies, abstracts of the studies were screened for identification of eligible manifests as a tubular opacity parallel to studies, full text articles were obtained and the right heart border, which simulates a curved Turkish sword or a Scimitar, and assessed and a final list of included studies was made. This process was done hence the term Scimitar sign (1). It is a independently and in duplication by two kind of partially anomalous pulmonary venous return and one of the several reviewers and any disagreement was resolved by the 3rd reviewer. The kappa symptoms of congenital pulmonary statistic between two authors was 78% for venolobar syndrome. Scimitar syndrome is a rare association of congenital selecting the articles. cardiopulmonary anomalies consisting of a 3- RESULTS partial anomalous pulmonary venous connection of the right lung to the inferior 3-1. Epidemiology vena cava, right lung hypoplasia, heart This anomaly has an occurrence rate dextroposition, and anomalous systemic of about 1 to 3 per 100,000 live births. arterial supply to the right lung (2, 3). Since many patients do not show any Scimitar syndrome occurs exclusively on symptoms, true occurrence may be higher. the right side and it is essentially a mixture Generally, the symptoms of this syndrome of pulmonary hypoplasia and partial appear 7 months after birth, but they can anomalous pulmonary venous return occur in different ages (6). Many patients (PAPVR). Hemodynamically, there is an do not demonstrate any symptoms during acyanotic left to right shunt. The childhood except recurrent respiratory tract anomalous vein usually drains into either infection. Despite the lack of a definite inferior vena cava (most common), right genetic cause for this syndrome, it is atrium or portal vein. Draining a part or descripted at five different families, which the entire of right lung into the inferior are noted in this article (2, 3, 7). vena cava (IVC) occurs with an anomalous 3-2. Associated congenital cardiac right pulmonary vein, which is the anomalies hallmark of scimitar syndrome (4, 5). There are two different types of scimitar It has been reported that 19–31% of veins, first simple classic vein that runs patients with scimitar syndrome have from the middle of the right lung to the associated congenital cardiac anomalies, cardiophrenic angle and the second type is and atrial septal defect, with a probability double arched vein in the upper and lower of 70%, is the most common (4). Less lung zones, with drainage into the left frequent associations include tetralogy of atrium and inferior vein cava (4, 5). fallot, ventricular septal defects, patent ductus arteriosus, cortriatriatum, bicuspid 2- MATERIALS AND METHODS aortic valve and sub-aortic stenosis. Coronary artery abnormalities are We searched the main databases relatively rare associations. This paper including Medline (via PubMed), Scopus, reports some classic and special forms of Embase, and Google Scholar to November scimitar syndrome (7, 8). The infantile 2019. Also, the references list of selected scimitar reported in our population is records was reviewed. Following similar to the previous studies and includes keywords were used independently and in the classic scimitar, the bilateral scimitar, combination: Scimitar Syndrome AND Int J Pediatr, Vol.7, N.12, Serial No.72, Dec. 2019 10612 Ghandi and Farsi scimitar syndrome with scimitar vein shows poor prognosis during infancy. stenosis and contralateral left upper There are many factors contributing to pulmonary vein stenosis, and scimitar pulmonary hypertension including large syndrome with right and left pulmonary left to right shunt via the anomalous arterial stenosis at multiple levels (8, 9): pulmonary vein, right lung hypoplasia with Anomalous Origin of the Left Coronary reduced pulmonary vascular bed, Artery from the Pulmonary Artery pulmonary vein stenosis and obstruction, (ALCAPA), accessory diaphragm, and persistent pulmonary hypertension of eventration or partial absence of the the newborn (4, 16). Studies have diaphragm, phrenic cyst, horseshoe lung, suggested multiple factors for pulmonary esophageal and gastric lung, congenital hypertension including large left to right cardiac malformations (25% of cases) shunting by the anomalous pulmonary vein including Atrial Septal Defect (ASD), or other intra-cardiac lesions such as ASD ventricular septal defect and coarctation of or Ventricular Septal Defect (VSD). The the aorta (9). Ruggieri et al. and Kahraman main source of pulmonary hypertension in et al. reported the association of some patients with Scimitar syndrome and dysmorphic features, craniofacial and in infants with total anomalous pulmonary central nervous system anomalies and venous connection has been identified as renal agenesis with scimitar syndrome, pulmonary venous stenosis (4, 5). besides associations with Turner syndrome Pulmonary arterial hypertension with and VATER association (vertebral defects, infantile-type scimitar syndrome has been anal atresia, cardiac defects, tracheo- recognized as a cause of severe symptoms esophageal fistula, renal anomalies, and and poor outcomes. It is attributed to the limb abnormalities) reported in other following factors: 1) stenosis of the studies. The fact that half of the patients anomalous pulmonary veins, 2) the were the result of consanguineous presence of systemic arterial supply in the marriage and some malformation did not right lung, 3) reduction of the pulmonary fit with any syndrome may indicate a vascular bed on the right side, and 4) complex genetic cause (10, 11). A rare increased pulmonary blood flow from pulmonary malformation associated with anomalous drainage or the intra-cardiac 8% of reported cases of scimitar syndrome lesion (17, 18). There is an increased risk is horseshoe lung. An isthmus of the of heart failure when Scimitar syndrome is pulmonary parenchymal tissue that arises accompanied with other cardiac defect and from the right lung base is the typical pulmonary hypertension. The etiology of feature of horseshoe lung. Pulmonary pulmonary hypertension in infants with arterial and bronchial supply extends from scimitar syndrome is variable and may be the right lower lobe pulmonary artery and related to a decreased right-sided bronchus (12, 13). The combination of pulmonary vascular bed, scimitar vein scimitar syndrome and aortic coarctation is stenosis, and unappreciated systemic rare and the presence of a left-to-right collateral blood flow along with intra- shunt may lead to a development of cardiac shunts (19). pulmonary hypertension and Eisenmenger 3-4. Clinical manifestation physiology (14, 15). Classic findings on physical examination 3-3. Pulmonary hypertension in include a shift in heart sounds and cardiac Scimitar syndrome impulse to the right and a systolic murmur. Pulmonary hypertension, as one the best Auscultation of the lung is usually normal, indicators