Azygos and hemiazygos continuation: An occasional finding in emergency department

Abstract

Interruption of the inferior vena cava (IVC) with azygos continuation is a rare congenital anomaly, in which the IVC is interrupted below the hepatic vein and venous return beyond this point is restored by the dilated azygos and hemiazygos veins draining into the superior vena cava. A case of the interruption of the IVC with azygos/emyazygos continuation for the absence of the hepatic segment of IVC, left renal vein duplication, and polysplenia is reported. The embryologic, clinical, and radiological significance are discussed. The diagnosis is suggested by X-ray, but contrast-enhanced multidetector computed tomography is the method of choice to diagnose this venous anomaly and reveals the aberrant vascular structures. Awareness of different congenital anomalies of IVC is important to surgeons and cardiologists and is necessary for radiologists to avoid diagnostic pitfalls and for preoperative planning: they should be remembered because they can influence several surgical interventions and endovascular procedures. Accidental ligation of the azygos vein is fatal and cardiac catheterization using the lower extremity vein is troublesome in patients with this condition.

Duplication of the Inferior Vena Cava, Azygos Continuation and Retro Aortic Renal Vein: Fortuitous Discovery

“…This congenital abnormality may be isolated, but is often part of a more complex syndrome that includes heart defects, situs inversus or polysplene syndrome [1] [10] [12]. In our observation, this anomaly was isolated.…”

“…It can be suspected before a mediastinal enlargement to the chest radiography evoking in addition a right paratracheal mass or a para-vertebral polyadenopathy [2] [3] [13]. It can Forensic Medicine and Anatomy Research also mimic aortic pathology, because these dilated vessels are parallel to the descending thoracic aorta, and can be confused with aortic pathology (dissection, aneurysm or rupture) during trans-esophageal echocardiography [1].…”

“…It is important to know the anatomy of this variant before planning a cardiac bypass, cardiac catheterization, azygo ligature during a thoracotomy or porto-cave decompression surgery [1] [2] [16].…”

“…The prevalence of IBV developmental abnormalities in the general population ranges from 0.07% to 8.7% [1]. They are usually discovered during autopsies, but are increasingly found with the latest imaging techniques [2].…”

Azygos Vein Aneurysm Mimicking a Mediastinal Mass

“…AVA has been described in both male and female patients, with a higher occurrence rate in women but with no significant difference when it comes to patients' age or sex (9). The normal calibre of the azygos vein is lower than 5mm, thus, all cases presenting larger dimension of this structure are considered as AVA (10). Regarding the development of the azygos vein, during the 4 th week of gestation venous blood is drained through the anterior and posterior cardinal veins, while a week later, the supracardinal veins are developed, later giving rise to the azygos vein.…”