CONTENTS
- Causes
- Signs & symptoms
- Diagnosis: CT scan findings
- Grading system to define severity
- Management:
- Pathophysiology & anatomy
- Questions & discussion
abbreviations used in the pulmonary section: 5
- ABPA: Allergic bronchopulmonary aspergillosis 📖
- AE-ILD: Acute exacerbation of ILD 📖
- AEP: Acute eosinophilic pneumonia 📖
- AFB: Acid Fast Bacilli
- AIP: Acute interstitial pneumonia (Hamman-Rich syndrome) 📖
- ANA: Antinuclear antibody 📖
- ANCA: Antineutrophil cytoplasmic antibodies 📖
- ARDS: Acute respiratory distress syndrome 📖
- ASS: Antisynthetase Syndrome 📖
- BAL: Bronchoalveolar lavage 📖
- BiPAP: Bilevel positive airway pressure 📖
- CEP: Chronic eosinophilic pneumonia 📖
- CF: Cystic fibrosis 📖
- COP: Cryptogenic organizing pneumonia 📖
- CPAP: Continuous positive airway pressure 📖
- CPFE: Combined pulmonary fibrosis and emphysema 📖
- CTD-ILD: Connective tissue disease associated interstitial lung disease 📖
- CTEPH: Chronic thromboembolic pulmonary hypertension 📖
- DAD: Diffuse alveolar damage 📖
- DAH: Diffuse alveolar hemorrhage 📖
- DIP: Desquamative interstitial pneumonia 📖
- DLCO: Diffusing capacity for carbon monoxide 📖
- DRESS: Drug reaction with eosinophilia and systemic symptoms 📖
- EGPA: Eosinophilic granulomatosis with polyangiitis 📖
- FEV1: Forced expiratory volume in 1 second 📖
- FVC: Forced vital capacity 📖
- GGO: Ground glass opacity 📖
- GLILD: Granulomatous and lymphocytic interstitial lung disease 📖
- HFNC: High flow nasal cannula 📖
- HP: Hypersensitivity pneumonitis 📖
- IPAF: Interstitial pneumonia with autoimmune features 📖
- IPF: Idiopathic pulmonary fibrosis 📖
- IVIG: Intravenous immunoglobulin 📖
- LAM: Lymphangioleiomyomatosis 📖
- LIP: Lymphocytic interstitial pneumonia 📖
- MAC: Mycobacterium avium complex 📖
- MCTD: Mixed connective tissue disease 📖
- NIV: Noninvasive ventilation (including CPAP or BiPAP) 📖
- NSIP: Nonspecific interstitial pneumonia 📖
- NTM: Non-tuberculous mycobacteria 📖
- OHS: Obesity hypoventilation syndrome 📖
- OP: Organizing pneumonia 📖
- OSA: Obstructive sleep apnea 📖
- PAP: Pulmonary alveolar proteinosis 📖
- PE: Pulmonary embolism 📖
- PFT: Pulmonary function test 📖
- PLCH: Pulmonary Langerhans cell histiocytosis 📖
- PPFE: Pleuroparenchymal fibroelastosis 📖
- PPF: Progressive pulmonary fibrosis 📖
- PVOD/PCH Pulmonary veno-occlusive disease/pulmonary capillary hemangiomatosis 📖
- RB-ILD: Respiratory bronchiolitis-associated interstitial lung disease 📖
- RP-ILD: Rapidly progressive interstitial lung disease 📖
- TNF: tumor necrosis factor
- UIP: Usual Interstitial Pneumonia 📖
malignancy (~70%)
- Non-small cell lung cancer (~50% of malignant etiologies).
- Small cell lung cancer (~25% of malignant etiologies).
- Lymphoma (~10% of malignant etiologies).
- Others:
- Thymoma or thyroid malignancy.
- Primary germ cell neoplasms.
- Mesothelioma.
- Esophageal cancer.
- Solid tumors with mediastinal lymph node metastasis (e.g., breast cancer).
device-related thrombosis (~25%)
- Pacemaker/defibrillator.
- Hemodialysis catheter.
- Central venous catheter.
- Chronic central venous port.
lymphadenopathy
- Infection (e.g., histoplasmosis, tuberculosis).
- Sarcoidosis.
mediastinal fibrosis
- Radiation fibrosis.
- Idiopathic fibrosis.
other
- Retrosternal thyroid.
- Aortic aneurysm.
- Mediastinal hematoma.
- Spontaneous thrombosis due to thrombophilia or Behcet disease. (33103626)
Severity relates to how rapidly occlusion develops, because a gradually developing occlusion may lead to collateral venous drainage.
edema & plethora (redness)
- Facial and neck edema (including periorbital/conjunctival edema).
- Arm swelling.
- Plethora (redness) of the face and neck.
venous distension
- Distended neck veins.
- Distended chest veins (these develop gradually, so prominently dilated subcutaneous veins on the chest may imply a more subacute disease course).
pulmonary involvement (due largely to airway edema)
- Stridor, hoarseness.
- Dyspnea, sometimes with orthopnea.
- Tongue swelling.
- Cough.
cerebral perfusion affected (including cerebral edema)
- Headache (may be worse lying flat or bending over). (30037444)
- Blurry vision.
- Dizziness, especially when leaning forward. (33357528)
- Altered mental status (including confusion, obtundation).
impaired cardiac output
- This is uncommon, but may be more likely in some situations:
- Acute SVC thrombosis.
- Pre-existing heart failure.
- Coexisting pulmonary emboli due to thrombus formation in the SVC.
- Mass compresses both the SVC and also the heart and/or pulmonary arteries. (33103626)
If SVC syndrome is suspected, this should be communicated with the radiology department, since multiphase imaging could improve diagnostic yield. (33103626)
direct evidence of obstruction
- Extrinsic compression vs. thrombosis.
indirect evidence
- Collateral vessel dilation implies a more clinically relevant occlusion.
- Collateral venous drainage into the portal venous system may rarely cause contrast enhancement to occur near the falciform ligament (“CT quadrate lobe hot spot sign”). (36062219)
Grade 0 (asymptomatic, ~10%)
- Radiographic superior vena cava obstruction in the absence of symptoms.
Grade 1 (mild, ~25%): symptoms may include
- Edema in head or neck (vascular distention).
- Cyanosis and/or plethora.
Grade 2 (moderate, ~50%)
- Edema in head or neck with functional impairment, such as:
- Mild dysphagia.
- Cough.
- Mild-moderate impairment of the head, jaw, or eyelid movements.
- Visual disturbances caused by ocular edema.
Grade 3 (severe, ~10%): one or more of the following
- Mild/moderate cerebral edema (e.g., headache, dizziness).
- Mild/moderate laryngeal edema.
- Diminished cardiac reserve (e.g., syncope after bending or coughing).
Grade 4 (life-threatening, ~5%): one or more of the following
- Significant cerebral edema (e.g., confusion, obtundation).
- Significant laryngeal edema (e.g., stridor).
- Significant hemodynamic compromise:
interventional radiology 🏆
stenting
- Basics:
- Advantages:
- High success rate.
- Fastest resolution of symptoms.
- Can be combined with other modalities (e.g., radiation, chemotherapy).
- Disadvantages:
- Major complications are rare, but can occur: (33103626)
- Stent migration, re-occlusion, or malposition.
- Pericardial tamponade if SVC perforation occurs below the level of the azygos vein).
- Hemothorax.
- Pulmonary edema (due to increased venous return).
- Lower long-term durability compared to surgery, so may be less ideal for patients with long life expectancy.
- May not be an option in patients with pacemakers/defibrillators (stenting can entrap the pacer lead).
- Major complications are rare, but can occur: (33103626)
thrombectomy
- Thrombus may be removed using aspiration thrombectomy and/or catheter-directed thrombolysis.
angioplasty
- Angioplasty without stent insertion may be utilized for patients with pacemaker/defibrillator-related SVC stenosis.
tissue biopsy
- Tissue biopsy may be performed to determine the diagnosis in patients with lymphadenopathy or mass compressing the superior vena cava.
surgery
- Basics:
- Time to improvement: ~0-72 hours.
- Often involves the use of a saphenous vein graft to bypass the SVC. (33357528)
- Advantages:
- Could be considered in SVC syndrome from benign etiology (e.g., extensive venous thrombosis).
- Could be considered in SVC syndrome that isn't amenable to stenting.
- Might be more durable in some situations. However, saphenous vein bypass grafting remains vulnerable to re-occlusion.
- Disadvantages:
- Invasive surgery.
- May involve prolonged intubation.
- Higher rate of complications as compared to stenting (e.g., pulmonary embolism, deep venous thrombosis, mediastinal hematoma).
chemotherapy
- Chemotherapy is an option for chemosensitive tumors (e.g., small cell lung carcinoma, non-Hodgkin lymphoma, germ cell tumor).
- Time to improvement: ~1-2 weeks (depending on malignancy).
- Advantages:
- Provides treatment of systemic malignancy.
- Disadvantages:
- Delayed relief of symptoms.
radiation
- Radiation is an option for radiosensitive tumors (including non-small-cell lung carcinoma and low grade lymphomas that may not be highly chemosensitive).
- Time to improvement: ~3-30 days.
- Advantages:
- In some cases, may be used to provide definitive treatment of the malignancy (e.g., definitive chemoradiation for non-small-cell lung carcinoma).
- Disadvantages:
- Delayed relief of symptoms.
- Ineffective in up to 20% of patients. (33357528)
- Radiotherapy may exacerbate SVC obstruction by causing edema. (36062219)
- Complications may include SVC perforation, inhibition of collateral venous development.
- Radiation prior to tissue diagnosis of malignancy may subsequently obscure the diagnosis. (33357528)
general supportive care
- Elevation of the head of the bed.
- Intubation may be needed for patients with severe airway obstruction and/or obtundation.
diuresis
- Gentle diuresis may be considered to reduce venous pressure, but this isn't supported by high-quality data.
anticoagulation
- If there is a thrombus within the SVC, systemic anticoagulation with a heparin infusion is generally utilized.
- Factors that may suggest the presence of thrombosis: (33103626)
- SVC syndrome associated with indwelling devices (e.g., central lines, dialysis catheters, cardiac devices).
- More acute onset of symptoms.
- Radiological evidence of thrombosis (e.g., pulmonary embolism).
steroid
- Steroid is a niche therapy that may be considered for carefully selected patients.
- Potential indications for steroid:
- (1) Steroid may shrink any reactive lymphadenopathy or lymphoma (with the drawback that this may compromise subsequent tissue diagnosis of lymphoma).
- (2) Prophylaxis against radiation-induced edema.
definitive therapy
- Interventional radiology is generally the preferred therapy for critical SVC syndrome, since it may allow for immediate resolution (unlike chemotherapy or radiotherapy, which can take weeks to have an effect).
mechanisms of SVC syndrome may include:
- One or more of the following may be involved:
- External compression or direct invasion of the SVC.
- Intrinsic stenosis of the SVC (e.g., following indwelling catheter or pacemaker/defibrillator placement).
- Thrombosis of SVC (acute thrombosis may occur superimposed on compression or stenosis, leading to acute deterioration).
basic anatomy of the SVC
- The SVC has three major tributaries: the right and left brachiocephalic veins and the azygos vein.
anatomic types of SVC obstruction
- Brachiocephalic vein obstruction (pink panel above):
- Right brachiocephalic vein may empty via the azygos network.
- Upper SVC, above the azygos vein (yellow panel above):
- Azygos system functions as a collateral drainage network, draining blood into the (remaining) SVC.
- At the level of the azygos vein (blue panel above):
- This may be the most problematic location for an occlusion.
- Both the SVC and the Azygos system are blocked.
- Lower SVC, below the azygos vein (purple panel above):
- Blood flows backwards through the Azygos vein to drain into the IVC.
- Less severe symptoms occur, because blood can be rerouted around the obstruction via a relatively robust venous network.
To keep this page small and fast, questions & discussion about this post can be found on another page here.
Guide to emoji hyperlinks
- = Link to online calculator.
- = Link to Medscape monograph about a drug.
- = Link to IBCC section about a drug.
- = Link to IBCC section covering that topic.
- = Link to FOAMed site with related information.
- 📄 = Link to open-access journal article.
- = Link to supplemental media.
References
- 25229918 Kumar B, Hosn NA. Images in clinical medicine. Superior vena cava syndrome. N Engl J Med. 2014 Sep 18;371(12):1142. doi: 10.1056/NEJMicm1311911 [PubMed]
- 30037444 Zimmerman S, Davis M. Rapid Fire: Superior Vena Cava Syndrome. Emerg Med Clin North Am. 2018 Aug;36(3):577-584. doi: 10.1016/j.emc.2018.04.011 [PubMed]
- 33103626 Klein-Weigel PF, Elitok S, Ruttloff A, Reinhold S, Nielitz J, Steindl J, Hillner B, Rehmenklau-Bremer L, Wrase C, Fuchs H, Herold T, Beyer L. Superior vena cava syndrome. Vasa. 2020 Oct;49(6):437-448. doi: 10.1024/0301-1526/a000908 [PubMed]
- 33357528 Azizi AH, Shafi I, Shah N, Rosenfield K, Schainfeld R, Sista A, Bashir R. Superior Vena Cava Syndrome. JACC Cardiovasc Interv. 2020 Dec 28;13(24):2896-2910. doi: 10.1016/j.jcin.2020.08.038 [PubMed]
- 36062219 Quencer KB. Superior Vena Cava Syndrome: Etiologies, Manifestations, and Treatments. Semin Intervent Radiol. 2022 Aug 31;39(3):292-303. doi: 10.1055/s-0042-1753480 [PubMed]
Books:
- Shah, P. L., Herth, F. J., Lee, G., & Criner, G. J. (2018). Essentials of Clinical pulmonology. In CRC Press eBooks. https://doi.org/10.1201/9781315113807
- Shepard, JO. (2019). Thoracic Imaging The Requisites (Requisites in Radiology) (3rd ed.). Elsevier.
- Walker C & Chung JH (2019). Muller’s Imaging of the Chest: Expert Radiology Series. Elsevier.
- Palange, P., & Rohde, G. (2019). ERS Handbook of Respiratory Medicine. European Respiratory Society.
- Rosado-De-Christenson, M. L., Facr, M. L. R. M., & Martínez-Jiménez, S. (2021). Diagnostic imaging: chest. Elsevier.
- Murray & Nadel: Broaddus, V. C., Ernst, J. D., MD, King, T. E., Jr, Lazarus, S. C., Sarmiento, K. F., Schnapp, L. M., Stapleton, R. D., & Gotway, M. B. (2021). Murray & Nadel’s Textbook of Respiratory Medicine, 2-Volume set. Elsevier.
- Fishman's: Grippi, M., Antin-Ozerkis, D. E., Cruz, C. D. S., Kotloff, R., Kotton, C. N., & Pack, A. (2023). Fishman’s Pulmonary Diseases and Disorders, Sixth Edition (6th ed.). McGraw Hill / Medical.