Teaching Case

An-eight-month old female baby with a history of chronic constipation was referred to the radiology department for barium enema examination.

During the barium enema procedure, reversal of colonic position was detected, and showed almost normal calibre and haustrations of bowel loops. The sigmoid colon, descending colon and splenic flexure were located in the right side of the abdomen while the hepatic flexure and ascending colon were observed in the left side of the abdomen (Fig. 1). Chest X-ray demonstrated right-sided position of the heart (dextrocardia, the liver on the left and stomach on the right side of the abdomen (Fig. 2). Ultrasound demonstrated the spleen in the right upper abdomen (Fig. 3) and the liver in the left upper abdomen (Fig. 4) confirming the presence of situs inversus dextrocardia.

Situs inversus is a term used when the internal organs of the body have reversed position. The total transposition of all thoracic and abdominal viscera is called situs inversus totalis or situs inversus dextrocardia [1]. Dextrocardia is a term used for congenital reversed position of the heart when the cardiac apex is pointing to the right [2]. Two different types can be differentiated: a) situs inversus dextrocardia, meaning that the heart is just mirrored (right chambers are still anterior to the left chambers) and b) dextroversion, where the heart is rotated to the right and left atrium and ventricle are anterior of their right counterparts [3]. Situs inversus dextrocardia is a rare congenital anomaly which occurs in about 1/6000 to 1/ 35000 of live births [4]. This is an autosomal recessive genetic disorder in which the defect occurs in chromosome 14. The primitive loop during embryonic development traverses into the opposite direction of normal position resulting in organ displacement [5]. In situs inversus totalis the morphological left atrium is located on the right side and the morphological right atrium is on the left side. Also the lungs and abdominal organs have reversed positions as the left lung has three lobes and the right lung two lobes. The liver, gall bladder, ligament of Treitz, ileum and ascending colon are located on the left, and the spleen, stomach, jejunum and descending colon are on the right side [2]. This congenital anomaly affects both males and females equally. The affected individuals are usually asymptomatic but in 3-5% of cases congenital cardiac anomalies can occur. Atrioventricular discordance and transposition of great vessels are the commonest associated abnormalities while a right-sided aortic arch occurs in about 80% of cases [6]. Almost 20% of people with situs inversus suffer from chronic sinusitis, bronchiectasis and nasal polyposis, called Kartagener syndrome [7]. A very rare type of situs inversus is accompanied with a normal left-sided cardiac position, called situs inversus with levocardia. This anomaly is seen with congenital cardiac anomalies in about 95% of cases. The affected population with situs inversus dextrocardia usually does not need any specific treatment, except if they are symptomatic or if a further congenital cardiac anomaly is present. However, recognition of this congenital condition is essential when any interventional procedure or surgery is to be undertaken [8].