British Journal of Radiology (2007) 80, e122-e124
© 2007 British Institute of Radiology
doi: 10.1259/bjr/31792102
Symptomatic interrupted inferior vena cava: report of a case presenting with haematochezia
Z Koc, MD,
S Ulusan, MD,
L Oguzkurt, MD and
E Serin, MD
Ba
kent University, Adana Teaching and Medical Research Centre, Department of Radiology, Adana, Turkey
Correspondence: Zafer Koc, Bakent Universitesi Adana Hastanesi, Dadalo
lu Mah, Serin Evler 39, Sok. No: 6, 01250 Yüreir, Adana, Turkey. E-mail: koczafer{at}gmail.com; zaferkoc{at}superonline.com
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Abstract
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Interrupted inferior vena cava (IVC) is a rare developmental defect. IVC interruption is usually accompanied with azygos and hemiazygos continuation, and is asymptomatic. Here, we report the imaging findings of a patient with an interrupted IVC with diffuse collaterals between the infrarenal IVC and large renal veins, left gonadal, and perirectal haemorrhoidal-portal collateral veins with associated haematochezia. Depending on the haemodynamic changes, interrupted IVC may cause possible different clinical findings as presented here.
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Introduction
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Anatomic variants and anomalies of the inferior vena cava (IVC) are infrequent and interrupted IVC is a rare anomaly. Non-invasive imaging modalities such as CT and MRI allow better identification of these anomalies. In general, existence of IVC anomalies has been important for pre-operative identification that could prevent morbidity and allow better planning of operative procedures such as aortic and renal surgery [1]. Recently, some of the IVC anomalies without any associated condition have been shown to be risk factors for diseases such as DVT (deep vein thrombosis) and pulmonary embolism [2]. In this report, we document a patient with infrarenal interrupted IVC, diffuse systemic and caval-portal venous collaterals with haematochezia as a distinctive presentation.
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Case report
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A 51-year-old man presented with fresh rectal bleeding and lower abdominal-inguinal pain of 2 days' duration. His blood pressure and pulse rate were within normal range. He has had type 2 diabetes mellitus of 3 years' duration. His general condition on admission was good and past medical history revealed no trauma or surgery. Haematochezia ceased on the second day of hospitalization.
Laboratory findings showed moderate leukocytosis that subsequently resolved. His haemoglobin level dropped from 146 g l–1 to 130 g l–1 on the second day and was stable at 130 g l–1 on the third day (reference intervals 140–180 g l–1). Results of blood chemistry analyses revealed normal liver and renal function tests. Laboratory values for thrombophilia including protein C and S, antithrombin III, protein C resistance and homocystein levels were all normal. Colonoscopic examination revealed increased submucosal vascularity in the ascending colon, and mucosal hyperaemia and internal haemorrhoids.
Ultrasound examination revealed dilated varicose collateral veins in the left renal hilum and left para-aortic region. Contrast-enhanced multidetector row CT (MDCT) revealed a 2 cm atretic segment of the IVC just below the level of the renal veins. MR angiography showed absence of the flow in this segment of the IVC. Diffuse collateral venous circulation was identified between the infrarenal IVC and large renal veins via both perirenal retroperitoneal, paravertebral and left gonadal veins. Left paravertebral-perirectal dilated collateral veins were also observed (Figure 1
). The drainage of blood from the lower half of the body to the suprarenal IVC coursed through the diffuse collateral veins between the infrarenal IVC and enlarged renal veins, and both perirenal-retroperitoneal collateral veins. Perirectal collateral veins, varicose dilatation of the left gonadal vein and varicoceles also were observed on the left side (Figure 1). The suprarenal and hepatic segments of the IVC appeared completely normal.
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Figure 1. (a) Coronal straight and (b,c) curved planar thin-slab maximum intensity projection CT angiography images showing atretic segment of the inferior vena cava (IVC) (double arrows), right perirenal retroperitoneal (small arrows), left paravertebral-gonadal (large arrows) collateral veins, and perirectal-haemorrhoidal venous collateral veins (small arrows in (c)). Large renal veins are seen as a sign of collateral circulation. Left varicocele is also seen (curved arrow in (a)). (d) Coronal curved planar maximum intensity projection MR angiography image showing no detectable flow in the atretic segment of the IVC (double arrows).
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Discussion
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Anomalies of the IVC occur in less than 1% of patients and can be readily recognized on multidetector row CT and MR angiography [2]. With advances in non-invasive vascular imaging, anatomic variants and anomalies of the IVC have become more commonly recognized in routine practice [2]. The embryologic basis of the infrarenal interrupted IVC is not truly understood, and there is controversy as to whether these conditions are true embryonic anomalies or the result of perinatal IVC thrombosis [3].
Interrupted IVC usually involves the suprarenal segment, is mostly accompanied by azygous or hemiazygous continuation and is usually asymptomatic [3, 5–8]. Infrarenal interrupted or absent IVC has also been reported [3]. With obstruction of the IVC, venous blood from the inferior part of the body returns to the heart through four major pathways: deep, intermediate, superficial and portal [2, 6]. In our case, collateral circulation was observed through three pathways: perirenal retroperitoneal and paraspinal-extravertebral (deep), the left gonadal vein to the left renal vein (intermediate), and the internal iliac vein to the haemorrhoidal plexus through the inferior mesenteric vein (portal).
Interrupted infrarenal IVC with diffuse venous collaterals between the infrarenal IVC and renal veins, and perirectal caval-portal collaterals causing haemorrhoids and/or haematochezia, as in our case, has not been described previously. Short segmental atresia such as this most likely stems from a fusion defect between the subrenal and renal segment of the IVC. Presence of the perirectal caval-portal collaterals made us consider that the cause of the haemorrhoids was secondary to the collateral circulation.
Knowledge of the presence of variant venous anatomy is important for surgical and interventional procedures [1]. Venous compression syndromes such as nutcracker syndrome or iliac vein compression syndrome are variations of normal anatomy and may cause clinical diseases [9]. Nutcracker syndrome can cause varicocele and pelvic congestion syndrome [9], whereas iliac vein compression syndrome is a risk factor for left sided deep vein thrombosis [10]. Although some of these syndromes have been known for a long time, new generation cross-sectional imaging devices such as MDCT unveil more clinical abnormalities caused by congenital anomalies. Recent reports point out that interruption of the IVC alone can be a risk factor for the development of deep vein thrombosis or pulmonary embolism [2]. The reported case is an example of another clinical sign caused by interrupted IVC. Haemorrhoids might be caused by increased pressure in the haemorrhoidal and mesenteric veins caused by interrupted IVC. Colonoscopic examination findings of increased submucosal vascularity and mucosal hyperaemia in the ascending colon support this assumption. This may be similar to the case of external pressure on the veins, which sometimes causes dilatation of the more peripheral veins, resulting in varicocele or pelvic congestion syndrome.
In conclusion, interrupted IVC have been more commonly diagnosed by use of newer cross-sectional imaging methods and some of these anomalies have been shown to be clinically important. Depending on the haemodynamic changes, interrupted IVC may cause different clinical findings, as presented here. The presence of and bleeding from haemorrhoids, although rare, can be a sign caused by congenital interruption of the IVC.
Received for publication February 13, 2006.
Revision received March 31, 2006.
Accepted for publication April 10, 2006.
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Abstract
Introduction
