VCU Department of Radiology
VCU Medical Center
Case of the Week: August 24-August 31, 2020
76- year old male presenting as a trauma status post fall resulting in right sided rib fractures with concern of a subclavian vein injury.
What is your diagnosis?
(Click for a larger image.)
On the initial CTA, we see patient right subclavian vasculature (artery and vein). The next CTA, from one week later, demonstrates marked enhancement and prominence of collateral vasculature within the soft tissues of the right upper chest.
Diagnosis: Thoracic outlet syndrome
Anytime prominent collateral vasculature is seen in the upper chest, it should prompt a close evaluation of the more central venous vasculature. Upon doing so, focal occlusion of the right subclavian vein is not seen, which was previously widely patient. This occurs at the site of vein crossing between the clavicle and first rib. In reviewing the prior images, it is noted on the topogram, that the patient’s arms were down, whereas on the more recent exam the patient’s arms are up.
This is an example of thoracic outlet syndrome. This is a term used to describe congenital and acquired etiologies resulting in compression of the subclavian vessels (vein or artery) or brachial plexus. Diagnosis can be tricky and usually requires a level of clinical suspicion. If requested, CTA study of the chest may be performed with patient’s arms both up and down to try and elicit a change in vascular patency or a triggering of patient’s symptoms. In this case, we accidentally got the information due to difference in technique between our trauma and regular CT chest protocols.
Neurogenic thoracic outlet syndrome, affecting the brachial plexus, is the most variant and accounts for 90-95% of cases. This will often result in patient symptoms of pain, paraesthesia, or numbness of the upper extremity.
Venous thoracic outlet syndrome, affecting the subclavian vein, is the second most common variant. This will cause upper limb swelling and pain as the blood has difficulty leaving the extremity. Further sub-variants of this include Paget-Schroetter syndrome with venous thrombosis and McCleery syndrome with intermittent venous compression and no thrombus formation.
The lest common variant, accounting for less than 3% of cases, is the arterial thoracic outlet syndrome, affecting the subclavian artery; however, this may be the variant with the most drastic clinical presentation and potentially leading to the most morbidity. As the subclavian artery is affected, blood cannot reach the upper extremity and patients can present with symptoms of ischemia (coolness, pallor, claudication, paresthesia, and diminished pulses). This can also result is shedding of distal emboli to the upper extremity.
Typically, surgical intervention is needed for definitive treatment. Stenting is not well tolerated due to the extrinsic compressive forces which will collapse and damage the stent. The venous variants may be treated more conservatively in the absence of thrombus formation to include anticoagulation and thrombolysis.