SITUS INVERSUS ASSOCIATED WITH COMPLEX VENOUS ANATOMY; A RARE ASSOCIATION

Syed Muzzammil Wasti, Sohail Amin, Sibtain Raza, S. Shafqat-ul-Islam, Syed Mahmood

Karachi X Rays & U/S / CT Scan CentreINTRODUCTIONSitus Inversus literally means mirror image arrangement of the Situs Solitus. It is a rare condition with a frequency of 0.01%. If it is found to be associated with dextrocardia and chance of congenital heart diseases is 3-5 %. Levocardia is an extremely rare association. But when Situs Inversus is associated with Levocardia, chance of congenital heart diseases rises to 95 %1.Since Situs Inversus has numerous associated anomalies, so most of the patients come to clinical and imaging attention because of congenital heart disease, immune deficiency, or bowel obstruction related to malrotation2. It may also result in atypical presentation of typical diseases leading to misdiagnosis. Establishing a good understanding of multiple anatomic variations, anomalies, associations and differences in clinical manifestations of disease process is of paramount importance. CASE REPORTA 14 years old young male presented with a history of lower backache, mild dysuria and supra-pubic pain for the last 01 year. It was not associated with fever, increased frequency, urgency or hesitancy. This patient had a history of congenital cardiac anomalies which were known to him. He however denied any history of previous hospitalization. There were no other known co-morbid. Overall growth pattern, milestones and secondary sexual characteristics were well developed. His previous ultrasound abdomen revealed Situs Inversus which was known to the patient as well. The imaging was performed on 16 slicer CT-Scanner. The scan revealed Dextro-cardia, Situs Inversus along with ectopic right kidney which was fused with the left kidney at its lower pole (Fig I & II). In addition to that ectopic right kidney was also malrotated, extending to the midline and laid anterior to the Aorta and IVC (Fig III). Slight malrotation of left kidney was also noted with associated left pelvi-utreteric junction narrowing leading to dilatation and ballooning of left renal pelvis. Striated nephrogram and duplex type of collecting system was noted on right side with dilatation of both moieties. Renal pelvis of both moieties showed abrupt tapering most likely due to pelvi-utreteric junction narrowing. No contrast was seen in right ureter and it was seen to be dilated up to the uretero-vesical junction. Vascular anatomy (Fig IV) raised the possibility of having double IVC (seen to be uniting at infra-hepatic level). Rest of the scan was unremarkable

a) Situs Inversus along with ectopic right kidney, two IVC are seen, one anterior to aorta on this image and other on left sideDISCUSSIONAnomalies related to Situs are quite unusual or even very rare at times. Situs Inversus is considered as the most common form which is seen only in 0.01% of the whole population1. Establishing a good understanding of these variations certainly becomes helpful to avoid complications in surgical or interventional procedures2. Situs Inversus either have an associated Dextrocardia or Levocardia. Situs Inversus is relatively common with the former one and is seen to have transposition of cardiac apex, spleen, stomach, and aorta on the right and the liver and IVC on the left. Cardiac diseases occur in 3-5% of cases3. Having an associated Levocardia is exceedingly rare and almost all cases have cardiac anomalies4. Congenital heart disease occurs in less than 1% of individuals with situs solitus5.Spectrum of manifestations varies greatly among those who present in early life than those who present late.

Unusual clinical manifestations and confusing pictures due to abnormal locations of spleen, gall bladder and appendix may present as diagnostic dilemma7. For appropriate recognition and characterization of visceral anatomy, Sonography8, Computed Tomography (CT), and Magnetic Resonance (MR) imaging have greatly enhanced the diagnostic abilities9.Situs Inversus has been found to be associated with various vascular anomalies and variations. Interruption of IVC with Azygous or Hemiazygous continuation is also seen in association with polysplenia 10, 11, 12. The infra hepatic IVC may be right sided, left sided or duplicated. However, IVC interruption with Azygous continuation in asplenia syndrome is very rare13. Ipsilateral location of the aorta and IVC has been reported to be a consistent finding in asplenia14. Applegate et al 15 noted that the aorta and IVC were ipsilateral in only six patients

c) Ectopic right kidney fused with the left kidney at its lower pole, large right paravertebral vein also seenb) Ectopic right kidney was also malrotated, IVC are seen to join at the level of renal hilum on this CT image REFERENCES

1 Dahnert W. CVS Disorders. In: Dahnert W, ed. Radiology Review Manual. 5th edition. Lippincott, Williams and Wilkins. 2003; pp.582 2 Moller JH, Nakib A, Anderson RC, Edwards JE. Congenital heart disease associated with polysplenia, a developmental complex of bilateral "left-sidedness". Circulation 1967; 36:789-799. 3 Applegate KE, Goske MJ, Pierce G, Murphy D. Situs revisited: imaging of the heterotaxy syndrome. Radiographics 1999;19:837-8524 Tegtmeyer CJ, Hust FS, Keats TE. Arteriographic manifestations of abdominal situs inversus. AJR Am J Roentgenol 1975; 125:427-4305 Tonkin IL. The definition of cardiac malpositions with echocardiography and computed tomography. In: Friedman WF, Higgins CB, eds. Pediatric cardiac imaging. Philadelphia, Pa: Saunders, 1984; 157-1876 Tonkin IL. The definition of cardiac malpositions with echocardiography and computed tomography. In: Friedman WF, Higgins CB, eds. Pediatric cardiac imaging. Philadelphia, Pa: Saunders, 1984; 157-187.d) Sagittal reformatted image showing fused kidneys with hydronephrosisSUMMARY OF IMAGING FINDINGS1. Situs Inversus with Dextrocardia2. Crossed Fused Ectopia of Right Kidney with duplex collecting system3. Bilateral Pelvi-Utreteric Junction narrowing4. Double IVC (seen to be uniting at renal hilum level)

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