|Year : 2018 | Volume
| Issue : 3 | Page : 168-170
Dextrocardia with situs inversus discovered incidentally on routine imaging
Mayowa Abimbola Soneye, Bukunmi Michael Idowu
Department of Radiology, Union Diagnostics and Clinical Services, Lagos State, Nigeria
|Date of Web Publication||1-Nov-2018|
Dr. Bukunmi Michael Idowu
Department of Radiology, Union Diagnostics and Clinical Services Plc, No 37 Tejuosho Street, Yaba, Lagos State
Source of Support: None, Conflict of Interest: None
This is a case of situs inversus totalis (SIT) in a 22-year-old woman who presented at our facility for routine medical examination of fitness. There were no cardiac or other symptoms to suggest the existence of the anomaly in her before this consultation. Chest radiography, abdominal ultrasonography, and computerized tomography of the abdomen (abdominal computed tomography) were done. This case is presented to illustrate the imaging features of SIT and highlight its implications for clinical and radiological practice. This case also adds to the growing body of literature on the existence of this anomaly in our environment.
Keywords: Dextrocardia, lateralization anomaly, Nigeria, positional anomaly, situs inversus
|How to cite this article:|
Soneye MA, Idowu BM. Dextrocardia with situs inversus discovered incidentally on routine imaging. J Clin Sci 2018;15:168-70
| Introduction|| |
Situs inversus is a rare entity described as a clinical state in which there is transposition of the intraabdominal and intrathoracic viscera. It is reported to occur in 1 in 8000–1 in 25,000 patients., This condition is usually an incidental finding which is often detected when such individuals present with usually unrelated signs and symptoms.
Situs solitus refers to normal anatomy in which anatomical structures that are supposed to be on the right are on the right and those that are supposed to be on the left are on the left.
Situs inversus can be divided into situs inversus with dextrocardia (situs inversus totalis [SIT]) and situs inversus with levocardia. The SIT is the more common variety.
Situs inversus can also be associated with other congenital anomalies including valvular defects, septal defects, and transposition of the great vessels.,,, Situs ambiguus is a disturbance in the usual left and right distribution of the thoracic and abdominal organs which does not entirely correspond to the complete or partial mirror image. Cases of SIT in humans and cadavers have been reported in Nigeria.,,
| Case Report|| |
A 22-year-old woman of Yoruba ethnic group presented for a routine medical evaluation of fitness. There was no history of acute or chronic symptoms or any other health complaint. There was normal development of secondary sexual characteristics and menstruation. There was no history of sinusitis. The general physical examination was normal. The systemic examination was also normal except for the cardiac apex beat which was palpated and auscultated in the right 4th intercostal space midclavicular line.
Full blood count, electrolytes/urea/creatinine assay, and hepatitis screening were normal.
Chest radiograph [Figure 1] showed normal heart size (cardiothoracic ratio = 0.47) with the apex located to the right of the midline, in keeping with dextrocardia. The aortic arch silhouette was also right-sided. The gastric air bubble was located under the right hemidiaphragm. The transposed cardiac anatomy was also depicted on coronal chest computed tomography (CT) [Figure 2].
|Figure 1: Chest radiograph (posteroanterior view) showing the apex of the heart (leftward arrow) to the right of the midline (dextrocardia), right-sided aortic arch (arrowhead), and gastric bubble under the right hemidiaphragm (upward arrow). No bronchiectasis|
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|Figure 2: Coronal-reformatted chest computed tomography (mediastinal window) showing dextrocardia (leftward arrow) with a right-sided aortic arch (arrowhead)|
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Ultrasound examination of the abdomen showed the liver and gallbladder in the left hypochondrion, while the spleen and the fluid-filled stomach were on the right side. The head of the pancreas was also oriented to the left. The uterus, adnexa, and urinary bladder appear normal.
Abdominal CT [Figure 3]a and [Figure 3]b also revealed complete transposition of the abdominal organs including the liver, gallbladder, spleen, pancreas, stomach, abdominal aorta, and inferior vena cava.
|Figure 3: (a) Axial abdominal computed tomography shows the liver (downward arrows) on the left while the stomach (star) and spleen (upward arrow) are on the right. The left kidney is marked with an arrowhead. (b) Axial abdominal computed tomography shows the stomach (downward arrow) and tail of pancreas (upward arrow) on the right, while the head of pancreas (star) and gallbladder (arrowhead) is on the right|
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The patient's unusual anatomy was explained to her; she was counseled appropriately, reassured, and had her fears allayed.
| Discussion|| |
Most cases of SIT are detected incidentally later in life when the individual seeks medical attention for other reasons. However, some may present earlier as a result of an associated abnormality of the pulmonary cilia, splenic abnormality, congenital cardiac diseases, or noncardiac congenital malformations (e.g., Kartagener's syndrome).,,,
There is no known cause of dextrocardia, but maternal diabetes mellitus and cocaine use by the mother have been implicated. Genetic factors are also suspected, with an increased incidence seen in conjoined twins., SIT shows no racial and sex predilection. Dextrocardia may be an isolated occurrence or coexist with situs inversus. Similarly, there can be situs inversus with or without dextrocardia. Dextrocardia with situs inversus SIT has a lower incidence of congenital cardiac abnormality compared to situs inversus with levocardia (0%–10% vs. 90%–95%).,
This anomaly poses a considerable danger of diagnostic challenges and/or iatrogenic mishaps when undetected before medical interventions. In cardiology, cardiopulmonary resuscitation chest compressions may be performed on the accustomed left instead of the right chest; SIT makes the interpretation of electrocardiographic (ECG) tracings difficult if the chest leads are not switched appropriately; chest pain of angina pectoris and myocardial infarction would be located in the right chest; probe placements for transthoracic echocardiography may require modifications; and the apex beat (palpation)/heart sounds (auscultation) would be on the right side during physical examination.
In surgery, the pain of appendicitis, cholecystitis/biliary colic, and diverticulitis may be localized opposite to the usual abdominal sites. The hepatic dullness to percussion would be elicited on the left – this has implications for the performance of transcutaneous hepatic biopsy, and similarly, placement of gastrostomy tubes. Considerable difficulties may be encountered and more planning required for organ transplantation. Care is also needed in identifying the colons at colonoscopy because the splenic and flexures would have been transposed. Longer operating times and ergonomic challenges have also been reported. The left-sided appendix may have pain on the right side in about 50% of ease. This is because the nervous component of the system is not reversed despite transposition of viscera. Consequently, more than 41% of inappropriate incisions have been reported.
In radiology and imaging, splenic flexure is on the right, while the hepatic flexure would be on the left on barium enema images; the location of the gastric shadow is reversed on barium meal; abdominal organs are transposed on sonography; there may be positioning challenges when performing procedures such as endoscopic retrograde cholangiopancreatography, catheter angiography, and percutaneous transhepatic cholangiography. In addition, positionally, anomalies are seen on chest radiography and cross-sectional imaging (chest/abdominal CT and magnetic resonance imaging [MRI]).
In sports medicine, individuals with SIT need to be evaluated thoroughly before being cleared to take part in competitive sports.
As has been noted, SIT may pose a significant obstacle to the localization of patient symptoms and institution of prompt treatment for acute emergencies such as appendicitis and cholecystitis.
The patient education is also paramount as this may help prevent surgical/medical accidents, especially when the doctor is unsuspecting.
The diagnosis can be suspected/confirmed on physical examination, chest radiography, abdominal ultrasound, ECG, echocardiography, chest and abdominal CT, MRI, catheter cardiac angiography, and radionuclide imaging.
In the absence of debilitating associated congenital cardiac anomalies, individuals with SIT tend to have a normal lifespan which might explain why it is often detected incidentally later in life.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]