Background

Question 1

What vessels form the SVC?

Answer 1

The right and left brachiocephalic veins join to form the SVC.

Question 2

What is SVC syndrome?

Answer 2

SVC syndrome is extrinsic or intrinsic obstruction of blood flow through the SVC, leading to venous congestion proximal to the obstruction.

Question 3

Describe the course of the SVC.

Answer 3

The SVC begins at the sternal angle, extends inferiorly along the right lat side of the ascending aorta, and inserts into the right atrium.

Question 4

What predisposes the SVC to compression?

Answer 4

The SVC is a thin-walled vessel with relatively low intravascular pressure and is therefore susceptible to compression by surrounding rigid structures including enlarged LNs and the trachea, sternum, pulmonary artery, and right main stem bronchus.

Question 5

What vessels form the collateral system of the SVC?

Answer 5

The collateral system of SVC is formed by the azygos, mammary, vertebral, lat thoracic, paraspinous, and esophageal vessels.

Question 6

What vessels join to form the azygos vein?

Answer 6

The right subcostal and right ascending lumbar veins coalesce to form the azygos vein.

Question 7

What is the most common cause of SVC syndrome?

Answer 7

Malignancy is the most common cause of SVC syndrome accounting for ∼60% of cases. Malignancy previously accounted for 90% of cases, but with increased use of implantable intravenous devices (i.e., central venous catheters, pacemaker leads), this has decreased. (McCurdy M et al., Crit Care Med 2012)

Question 8

Name 5 benign causes of SVC syndrome.

Answer 8

Benign causes of SVC syndrome:

Catheter-induced thrombosis
Chronic mediastinitis
Retrosternal goiter
CHF
Aortic aneurysm

Question 9

Name 6 cancers most commonly associated with SVC syndrome, in decreasing order of incidence.

Answer 9

Cancers associated with SVC syndrome:

```
NSCLC: 50%
SCLC: 22%
Lymphoma: 12%
Mets: 9%
Germ cell tumors: 3%
Thymoma: 2%
Wilson L et al., NEJM 2007
~~~

Question 10

Are NSCLC or SCLC pts more likely to develop SVC syndrome?

Answer 10

SCLC pts are more likely to develop SVC syndrome than NSCLC pts b/c of their propensity toward rapid growth in central airways.

Question 11

What is the most common cause of SVC syndrome in pts <50 yo?

Answer 11

In pts <50 yo, the most common cause of SVC syndrome is lymphoma.

Question 12

Which types of NHL are associated with SVC syndrome?

Answer 12

NHL types associated with SVC syndrome:

Diffuse large B-cell lymphoma
Lymphoblastic lymphoma
Primary mediastinal B-cell lymphoma

Question 13

What is the typical duration of Sx prior to presentation with SVC syndrome?

Answer 13

Pts with SVC syndrome may have Sx over days to wks but usually present within 1 mo of onset.

Question 14

Do most pts presenting with SVC syndrome have a prior cancer Dx?

Answer 14

No. Most pts presenting with SVC syndrome do not have a prior cancer Dx.

Question 15

Why is SVC syndrome considered an emergency?

Answer 15

SVC syndrome may cause airway obstruction and cerebral edema; however, severe Sx are uncommon, and life-threatening Sx are rare.

Question 16

What are the common presenting Sx of SVC syndrome?

Answer 16

Presenting Sx of SVC syndrome:

Face and neck swelling
UE swelling
Cough/stridor
Dyspnea
Dilated chest veins (collateral blood flow)
(Rice T et al., Medicine 2006)

Question 17

What is the most common Sx of SVC syndrome?

Answer 17

The most common Sx of SVC syndrome is facial swelling.

Question 18

What physical exam findings are associated with SVC syndrome?

Answer 18

Signs of SVC syndrome: facial plethora, facial edema, jugular venous distension, and visible collateral venous drainage on the ant chest