Situs Inversus Totalis Benign and Unusual

The parents of a 2-year-old boy with a 3-day history of fever took him to the emergency department. The child’s temperature fluctuated between 38°C (100.4°F) and 39°C (102.2°F). As part of the workup, chest films were taken. Anteroposterior and lateral chest radiographs demonstrated the incidental finding of situs inversus totalis with a right-sided aortic arch. The patient’s liver was noted to be on the left and the stomach on the right of the abdomen. The cardiac silhouette was difficult to visualize on the reversed lordotic projection. The lungs were clear; there was no pleural effusion. Vertebral anomalies were not seen. Dr Scott Springer and Scott C. Hollander of Long Island, NY, write that situs inversus may occur in the thorax, abdomen, or both. In cardiac situs inversus, the right atrium is located on the left side and the left atrium is on the right side; abdominal situs inversus involves the mirrorimage positioning of the abdominal organs. Situs inversus totalis refers to the presence of both conditions. It occurs in 1 in 1500 to 35,000 persons in the general population and is usually discovered incidentally on chest films.¹ A genetic cause of this anomaly is suspected, but the mode of inheritance is unclear. Dextrocardia, levocardia, and Kartagener syndrome are among the associated congenital conditions. ² In dextrocardia, the cardiac apex is directed rightward; a leftward cardiac apex is seen in levocardia. Classically, Kartagener syndrome presents with the triad of infertility, sinusitis, and situs inversus. Plain films, CT scans, sonograms, and barium studies can help delineate situs inversus and its variants. Nonradiographic clues to situs inversus include ECG changes with right axis deviation. On physical examination, the point of maximal impulse is on the right. The heart sounds are noticeably decreased on the left. A palpable liver edge on the left side of the abdomen and an auscultated gastric air bubble in the right upper quadrant also suggest situs inversus. The cause of this patient’s fever was acute otitis media, for which a 10-day course of amoxicillin was given. He recovered rapidly with no further complications from the infection or from the situs inversus totalis. Neither the child’s parents nor any other family member had situs inversus.