Anesthesiology, Article, Cardiology, Ultrasound

Bedside ultrasound identification of a duplicated inferior vena cava

Case Report

Bedside ultrasound identification of a duplicated inferior vena cava

Abstract

A 47-year-old man presented to the emergency department with upper abdominal pain radiating to his back. Other than mild, reproducible abdominal pain, he had a normal physical examination. A bedside ultrasound examination of his aorta was performed and demonstrated a third vascular structure on axial (short-axis) imaging of the abdomen. Computed tomography of his abdomen and pelvis confirmed a duplicated inferior vena cava. This anomaly is discussed in terms of its relevance to the emergency sonographer, with a brief review of the literature on the subject.

A 47-year-old man presented to the emergency department with a complaint of upper abdominal pain and back pain. He had been previously diagnosed with hypertension and had a 50-pack-year smoking history. His vital signs were within normal limits. On examination, his lung fields were clear to auscultation; and his heart was regular and without murmurs or rubs. His extremity pulses were 2+ and equal. On Abdominal examination, he had reproducible midEpigastric pain that extended to his umbilicus, without a palpable Abdominal mass. While laboratory studies were pending, a bedside ultrasound was performed (Fig. 1) to assess for Abdominal aortic aneurysm. Three vascular structures were identified on ultrasound examination, instead of the expected aorta and

Inferior vena cava .

Based ona concern for aortic dissection or some other vascular anomaly, an IV-contrasted computed tomography (CT) study of the abdomen/pelvis was performed. The result of the CT (Fig. 2) was notable for a duplicated IVC but was otherwise normal.

Duplicated IVC is a rare congenital anomaly with an incidence of 0.2% to 3.0% in the population [1,2]. Normally, the IVC derives from 3 paired veins during fetal development, although various anomalies may occur in the IVC during this dynamic process [3]. Duplication of the IVC is most commonly seen below the level of the renal vein. The left-sided IVC arises from the left common iliac vein, drains the left renal vein, and then crosses the aorta anteriorly or posteriorly to join the right IVC.

There are several implications to this anomaly. First, its presence can impact various retroperitoneal surgeries as well as the placement of IVC filters. Persistent pulmonary emboli may occur after the placement of an IVC filter in patients

Fig. 1 Transverse aorta flanked by the duplicated IVC (*). Vertebral body with expected acoustic shadowing. Ao indicates aorta; V, vertebral body.

with an unidentified duplication. In addition, there is suggestion of an association between duplicated IVC and the incidence of lower extremity deep venous thrombosis, particularly in young adults [3,4].

From a Bedside sonography perspective, a duplicated IVC alters the expected anatomy of the aorta examination. It may be confused for a saccular aortic aneurysm, enlarged aortolumbar lymph nodes, or aortic intimal abnormalities (eg, dissection) [5]. In the clinical scenario above, our uncertainty regarding the bedside ultrasound findings led to a contrasted CT, which confirmed the finding of duplicated IVC.

Fig. 2 Computed tomographic image showing the duplicated IVC, as indicated by the arrowheads.

0735-6757/$ – see front matter (C) 2011

245.e2 Case Report

As emergency physicians increasingly perform bedside ultrasound of the abdominal aorta, an awareness of this anomaly will be essential toward appropriately interpreting their sonographic studies.

Geoffrey E. Hayden MD

Carrie Klotz MD Department of Emergency Medicine Vanderbilt University Medical Center Nashville, TN 37232, USA

E-mail address: [email protected] doi:10.1016/j.ajem.2010.03.014

References

  1. Giordano JM, Trout HH. Anomalies of the inferior vena cava. J Vasc Surg 1986;3:924-8.
  2. Mayo J, et al. Anomalies of the inferior vena cava. AJR Am J Roentgenol 1983;140:339-45.
  3. Gayer G, et al. Congenital anomalies of the inferior vena cava revealed on CT in patients with deep vein thrombosis. AJR Am J Roentgenol 2003;180:729-32.
  4. Ruggeri M, Tosetto A, Castaman G, Rodeghiero F. Congenital absence of the inferior vena cava: a rare risk factor for idiopathic deep-vein thrombosis. Lancet 2001;357:441 [letter].
  5. Senecail B, Lefever C, Person H, Meriot P. Radiologic anatomy of duplication of the inferior vena cava: a trap in Abdominal imaging. Surg Radiol Anat 1987;9:151-7.

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