by Chris Little
Presentation on SVC Syndrome for Pulm Conference
1. What is SVC Syndrome
a. A Group of symptoms caused by obstruction of the SVC resulting in swelling of the face and arms. The majority of SVC syndromes are caused by direct malignant invasion or compression of the SVC.
2. Pathophysiology of SVC Syndrome
a. Direct tumor invasion of the vessel
b. Compression of the tumor extrinsically by primary tumor or by enlarged mediastinal lymph nodes
c. Thrombosis around indwelling intravascular devices (central lines, pacemakers).
d. Collaterals develop over several weeks to relieve the initially very high venous pressures distal to the obstruction (the net pressure is still elevated even after collateral dilation).
3. Etiology of SVC Syndrome (The superior vena cava syndrome: clinical characteristics and evolving etiology.)
a. Begnin causes 40% of cases (Intravascular devices = 71% of benign cases, fibrosing mediastinitis[slow infectious, histo] is the second most common). Post radiation fiberosis and nocardiosis are also possibilities. Agenesis of the SVC is also a rare cause.
b. malignant causes 60% of cases (Bronchogenic carcinoma #1, small cell 22% and NSCLC [often presents as pancoast] 24%were number 2 and 3), then lymphoma [diffuse large b-cell lymphoma] and germ cell tumors at 8% and 3%)
4. Signs and Symptoms
a. Patients frequently complain of facial swelling or head fullness, which may be exacerbated by bending forward or lying down, or arm swelling. Swelling of the head and neck is visually striking but generally of little clinical consequence. However, edema can narrow the lumen of the nasal passages and larynx, potentially compromising the function of the larynx or pharynx and causing dyspnea, stridor, cough, hoarseness, and dysphagia. Respiratory distress can also be related to pleural effusion or pulmonary restriction from severe chest or breast swelling.
b. Patients with cerebral edema may have headaches, confusion, or visual/auditory disturbances. Cerebral edema can lead to brainstem herniation, and possibly death.
c. The rapidity of onset of symptoms depends on the time course of SVC invasion or compression, and the severity of luminal compromise. The presence and severity of symptoms and signs of SVC obstruction in turn depends on whether recruitment of venous collaterals has compensated for the narrowing. Acute thrombosis of a prior stable partial obstruction can also occur, leading to abrupt symptoms.
d. Proposed Table for categorizing severity of symptoms:
a. Initial suspiscion typically comes from above mentioned symptoms
b. Then imaging must happen and is dependent on the level of severity
i. Grade 3 or 4, venography provides the most expedient diagnosis (catheter-based is preferred over CT as you can immediately intervene).
ii. Grade 1 or 2, you can image via venous duplex or CT with contrast, but CT is preferred as it can evaluate the contralaterall vessels for flow (a better indicator of SVC syndrome)
c. After imaging, typically tissue diagnosis follows imaging as tissue diagnosis is required for treatment options.
a. Goals are alleviate symptoms, and treat underlying condition
c. Underlying condition - don't start cancer specific therapy until tissue ID. For urgent cases, you can do endovenous stenting. For patient with severe vascular compromise, they require urgent recannulization. Intubation may be challenging in these patients as they have distorted anatomy.
d. radiation therapy in the acute setting is no longer recommended for patients without a tissue diagnosis.
e. systemic anticoagulation is typically warrented in patients with a thrombus.
f. thrombus around a CVC may require removal of the catheter
g. elevation of the head is likely beneficial, though no data exists to support the practice at this time
h. care should be taken when administering vesicants in the upper extremities (e.g. chemotherapy).
i. glucocorticoids may be used in patient with non-stentable SVC syndrome who are receiving emergent RT (for airway protection). They may also be useful in steroid responsive tumors like lymphoma and thymoma.
k. surgical options for SVC are typically limited.
a. Average life expectancy is 6 months with wide variability depending on underlying malignancy
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