Scimitar syndrome: diagnostic approach and management

The article presents a clinical case of scimitar syndrome in a child, who is 3 years old. The manifestation of clinical signs was observed in a child at the age of one month as paleness, perioral cyanosis and episode of apnea. This child was hospitalized for further examination. The girl had perioral cyanosis, SpO 2 90 %, respiratory rate is 36/min. Puerile breathing is auscultative in the lungs, and weakened on the right, on the anterior surface of the chest. Heart tones are rhythmic, systolic murmur is 2/6 at the upper left edge of the chest and 4/6 in the interlobular area on the left. Due to echocardiography it was diagnosed non-critical coarctation of the aorta, a secondary defect of the interventricular septum. Chest X-ray: in the area of the right pulmonary field there is an intense shadow from the apex to the level of the 5 rib with fuzzy edges. What does the child have: dextocardia, dextroposition, pneumonia, atelectasis or thymomegaly? Providing the bronchoscopy, it was revealed the obstruction of the bronchi of the upper and middle parts of the right lung with thick murmur of white color. The bronchial tree was rehabilitated. Saturation was normalized after bronchoscopy. But, despite the elimination of the cause of atelectasis, the control radiography was still unchanged. For further diagnosis, CT scan of the chest with contrast was performed. The child was diagnosed with scimitar syndrome in combination with aortic coarctation and aberrant right subclavian artery. Balloon dilation of aortic coagulation was performed at the age of 2.5 months. At the age of 2 years, surgical correction was performed — elimination of abnormal drainage of the pulmonary veins and the aortic arch plastic. Intraoperative anatomy: mesocardia, right heart sections are dilated, lower part of the right lung is hypoplasic. Our patient did not actually have symptoms characteristic of the scimitar syndrome because there were no signs of heart failure, the girl did not have respiratory disease. A diagnosis for a baby at infancy was made due to an aspiration episode. But atelectasis and mesocardia prevented visualization of the characteristic radiological feature of scimitar syndrome. Therefore, a complete study using contrast-enhanced CT is mandatory for such patients.

Abstract. The article presents a clinical case of scimitar syndrome in a child, who is 3 years old. The manifestation of clinical signs was observed in a child at the age of one month as paleness, perioral cyanosis and episode of apnea. This child was hospitalized for further examination. The girl had perioral cyanosis, SpO 2 90 %, respiratory rate is 36/min. Puerile breathing is auscultative in the lungs, and weakened on the right, on the anterior surface of the chest. Heart tones are rhythmic, systolic murmur is 2/6 at the upper left edge of the chest and 4/6 in the interlobular area on the left. Due to echocardiography it was diagnosed non-critical coarctation of the aorta, a secondary defect of the interventricular septum. Chest X-ray: in the area of the right pulmonary field there is an intense shadow from the apex to the level of the 5 th rib with fuzzy edges. What does the child have: dextocardia, dextroposition, pneumonia, atelectasis or thymomegaly? Providing the bronchoscopy, it was revealed the obstruction of the bronchi of the upper and middle parts of the right lung with thick murmur of white color. The bronchial tree was rehabilitated. Saturation was normalized after bronchoscopy. But, despite the elimination of the cause of atelectasis, the control radiography was still unchanged. For further diagnosis, CT scan of the chest with contrast was performed. The child was diagnosed with scimitar syndrome in combination with aortic coarctation and aberrant right subclavian artery. Balloon dilation of aortic coagulation was performed at the age of 2.5 months. At the age of 2 years, surgical correction was performed -elimination of abnormal drainage of the pulmonary veins and the aortic arch plastic. Intraoperative anatomy: mesocardia, right heart sections are dilated, lower part of the right lung is hypoplasic. Our patient did not actually have symptoms characteristic of the scimitar syndrome because there were no signs of heart failure, the girl did not have respiratory disease. A diagnosis for a baby at infancy was made due to an aspiration episode. But atelectasis and mesocardia prevented visualization of the characteristic radiological feature of scimitar syndrome. Therefore, a complete study using contrast-enhanced CT is mandatory for such patients.
Scimitar syndrome is a rare congenital pathology and occurs from 1 to 3 cases in 100,000 newborns, predominantly in girls. In 1836 the pathology was first described on an autopsy material by Dr. G. Cooper, who gave it a name because of the chest X-ray: a long and curved shadow on the right contour of the heart is similar to the blade of a yataghan. The morbidity and mortality of this pathology is considered to be low since most cases are identified by accident or at the autopsy [2,3].
Clinical features with scimitar syndrome vary greatly depending on age. Patients are diagnosed with early (infantile) type or late (infant/adult) type. In the neonatal period, scimitar syndrome is characterized by heart or respiratory failure, secondary pulmonary hypertension, and usually requires surgical treatment and a worse prognosis. There is tachypnea, decreased appetite, such children are lagging behind in physical development. Severe cases lead to cyanosis and pulmonary hypertension, which occurs as a result of constant discharge of blood from left to right due to the abnormal circulation in the right lung, and this leads to the increased pressure in the right parts of the heart. Pulmonary hypoplasia further shortens the circulatory system and, in combination with pulmonary vein obstruction or other congenital malformations, produces persistent pulmonary hypertension. When examined, the heart is shifted to the right, the auscultatory picture of the lungs is not changed or there is weakened breathing. The prognosis depends on the severity of concomitant anomalies, the level of pulmonary hypertension and the child's clinical condition [4].
Symptoms in the infant/adult type have a milder course. In adults, the defects of short pulmonary circumference are negligible: with no pulmonary hypertension in 77 % of cases or with pulmonary hypertension in 23 %. About a half of the patients diagnosed after their first year of living remain asymptomatic. Partial abnormal drainage of the pulmonary veins creates a left-right shunt, which is often not clinically manifested before the adulthood or is detected accidentally on chest radiographs after recurrent pulmonary infections. This type may be accompanied by fatigue, shortness of breath and recurrent pneumonia. If this defect has not been diagnosed and corrected in time, with age in the patients there are developed volume overload of the right heart departments, pulmonary hypertension, right ventricular failure and tricuspid regurgitation. Surgical treatment in the adult type is recommended to delay as much as possible providing conservative therapy for pulmonary hypertension.
Scimitar syndrome is diagnosed in 70 % of cases by means of echocardiography, which has high sensitivity and allows detecting other cardiac abnormalities. Threedimensional CT or MRI of the heart is fundamental to visualize abnormal pulmonary vein drainage and other anatomical features of a patient. Cardiac catheterization and angiography confirm the diagnosis, providing detailed information on the anatomy of defects and the severity of pulmonary hypertension that is important for planning surgical correction.
Treatment depends on the patient's age and symptoms. Newborns are treated for pulmonary hypertension.
Surgical treatment is recommended for children with severe heart failure, recurrent respiratory tract infections, or pulmonary hypertension resistant to the therapy. In the case of lung sequestration, lobectomy and blocking of an abnormal systemic flow by embolization or ligation of the server artery are required. Other congenital heart defects (septal defects, aortic coarctation, tetralogy of Fallot) should be clearly corrected. However, most researchers believe that all patients diagnosed with scimitar syndrome need surgical correction to prevent complications with age [5,6].
We bring to your attention a clinical case of a child with scimitar syndrome.
Olenka D. was born at the second pregnancy (gestation period of 38 weeks), the second physiological birth, birth weight of 3350. And the pregnancy in the mother ended with an early spontaneous miscarriage. She was first referred to a cardiologist at the age of one month because of paleness and perioral cyanosis. Due to echocardiography it was diagnosed non-critical coarctation of the aorta, a secondary defect of the interventricular septum of 0.6 cm and the child was admitted to the hospital for further examination.
The anamnesis shows that apnea and cyanosis were observed 4 days before hospitalization. The baby's aunt has a two-part right lung.
The child's condition is considered to be moderate and stable. Weight is 4 kg. Perioral cyanosis, SpO 2 90 %, respiratory rate is 36/min. Puerile breathing is auscultative in the lungs, and weakened on the right, on the anterior surface of the chest. Heart tones are rhythmic, systolic murmur is 2/6 at the upper left edge of the chest and 4/6 in the interlobular area on the left. Heart rate is 135/min, blood pressure is: right arm -83/36 mm Hg, left arm -80/35 mm Hg and leg -85/47 mm Hg. Pulsation is weake ned on the peripheral arteries. The liver is palpated along the edge of the costal arch. There is no edema.
Results of laboratory tests are within normal limits. ECG. Sinus rhythm, 135/min, right chart, incomplete blockage of the right leg of the bundle of His.
Echocardiography. Left ventricular: ultimate diastolic size of 1. Chest X-ray. In the area of the right pulmonary field there is an intense shadow from the apex to the level of the 5 th rib with fuzzy edges. The shadow of the heart is shifted to the right. On the left contour in the upper mediastinum there is a shadow of the thymus (Fig. 1). Taking into consideration such a radiographic picture, the question is, what does the child have: dextrocardia, dextroposition, pneumonia, atelectasis or thymomegaly? The absence of intoxication and inflammatory changes at the laboratory examination caused a doubt that it is the diagnosis of pneumonia. Taking into account the possible episode of aspiration, the radiographic picture was considered as atelectasis of the right lung with the shift of the mediastinum to the right. It was made a decision to provide a remedial diagnostic bronchoscopy.
Providing the bronchoscopy, it was revealed the obstruction of the bronchi of the upper and middle parts of the right lung with thick murmur of white color. The bronchial tree was rehabilitated. Saturation was normalized after bronchoscopy. But, despite the elimination of the cause of atelectasis, the control radiography was still unchanged.
For further diagnosis, CT scan of the chest with contrast was performed (Fig. 2, 3). Aortic coarctation and aberrant right subclavian artery were confirmed. Right pulmonary veins create a collector of up to 6 mm in size, which drains into the supradiaphragmatic part of the inferior vena cava. Narrowing is visualized in the place of inflow of the collector into the inferior vena cava.
The child was diagnosed with scimitar syndrome in combination with aortic coarctation and aberrant right subclavian artery. Balloon dilation of aortic coarctation was performed at the age of 2.5 months. The girl has been observed by a cardiologist for 2 years. As physical and psychomotor development is concerned, she kept up with her peers. Three times a year she was ill with respiratory diseases. During the observation, the pressure gradient at the coarctation of the aorta was kept within 10-13 mm Hg. At the age of 2 years, surgical correction was performedelimination of abnormal drainage of the pulmonary veins and the aortic arch plastic. Intraoperative anatomy: mesocardia, right heart sections are dilated, lower part of the right lung is hypoplasic.
The anatomical data of the child is a variant of scimitar syndrome: infracardiac form of partial abnormal drainage of the pulmonary veins with obstruction of the collector at the inflow into the inferior vena cava in combination with coarctation of the aorta, atrial septal defect, abnormal outflow of the right subclavian artery, and hypoplasia of the lower part of the right lung. The clinical picture of patients with scimitar syndrome is extremely diverse. Recurrent respiratory infections are characte ristic of scimitar syndrome. Recurrent pneumonia with scimitar syndrome may result from external airway compression by the collector of the pulmonary veins. Other mechanisms suggest impaired lymphatic drainage and insufficient local activity of lymphocytes and macrophages in the affected lung area [7]. Our patient did not actually have symptoms characte ristic of scimitar syndrome because there were no signs of heart failure, the girl did not have respiratory disease. A diagnosis for a baby at infancy was made due to an aspiration episode. But atelectasis and mesocardia prevented visua lization of the characteristic radiological feature of scimitar syndrome. Therefore, a complete study using contrast-enhanced CT is mandatory for such patients. Surgical correction of abnormal pulmonary vein drainage is required for symptoms of heart failure [8,9]. Instead, children in serious condition may need lobectomy or pneumonectomy [10]. However, it is the most difficult to make decision on treatment (surgical or medical) for children with mild scimitar syndrome, at the asympto matic course and having a random diagnosis, as in our case described here. For this purpose, it is necessary to observe the development of pulmonary hypertension.

Conflicts of interests.
Authors declare the absence of any conflicts of interests and their own financial interest that might be construed to influence the results or interpretation of their manuscript.