An enlarged/dilated azygos vein may result from a number of physiological as well as pathological causes. The enlarged azygos vein may be seen as a widened right paratracheal/paraspinal stripe on a frontal chest radiograph.
On this page:
Terminology
Spelling it "azygous" when referring to the vein is incorrect, regardless of whether British or American English 5. Azygous is a word in English meaning 'without pair', but in the context of anatomy, see Terminologia Anatomica, azygos vein is the sole correct spelling.
Causes for dilatation
There are a number of physiological causes for enlargement of the azygos vein such as pregnancy and over hydration, but most cases are pathological:
- azygos continuation of the inferior vena cava (IVC)
- aortoazygos fistula 1
- congestive heart failure (CHF)
- constrictive pericarditis
- congenital SVC interruption (distal to azygos entry)
- SVC obstruction (distal to azygos entry 3)
- congenital IVC interruption
- IVC obstruction
- pericardial effusion
- portal hypertension
- right ventricular strain
- tricuspid insufficiency
Differential diagnosis
The differential diagnosis depends on the radiographic study being reviewed; on a CXR, the differential includes:
Unable to process the form. Check for errors and try again.