Superior Vena Cava Obstruction Flashcards
What is superior vena cava obstruction (SVCO)?
SVCO is a clinical condition that occurs as a result of obstruction of the SVC, leading to interrupted venous return from the head, thorax and upper extremities to the right atrium.
Briefly describe the pathophysiology of SVCO
SVCO is a clinical condition that occurs as a result of obstruction of the SVC, leading to interrupted venous return from the head, thorax and upper extremities to the right atrium. The increased venous pressure results in oedema of the head, neck and arms, often with cyanosis, plethora and distended subcutaneous vessels.
It can be caused by intralumincal obsturction of the SVC or extrinsic compression.
What commonly causes SVCO?
A total of 65% of cases are due to malignancy. Lung cancer is the most common aetiology, non-small cell lung cancer accounting for 50% of cases of malignant SVC syndrome and small cell lung cancer for 25% cases.
Other causes:
Causes
- Lymphoma
- Other malignancies: metastatic seminoma, Kaposi’s sarcoma, breast cancer
- Aortic aneurysm
- Mediastinal fibrosis
- Goitre
- SVC thrombosis
What are the risk factors for SVCO?
- Smoking
- Multiple pacemaker leads
- Central venous catheters/ ports
- Age >50 years
- Radiation
What are the clinical features of SVCO?
- Localised oedema of the face and upper extremities
- Dyspnoea
- Facial plethora
- Cough
- Distended neck veins
- Distended chest veins
- Hoarseness of voice
- Lymphadenopathy
- Anorexia
- Headache
What test is used for SVCO?
Pemberton’s test.
Briefly describe Pemberton’s Test
Ask the patient to lift both arms as high as possible for more than 1 minute. This will elicit signs of facial plethora, cyanosis and venous congestion.
What investigations should be ordered for SVCO?
- Chest X-ray
- Chest CT
- Chest MRI
Why investigate using chest X-ray?
Ordered when SVCO is clinically suspected, especially with a history of pulmonary symptoms.
May show widened mediastinum or mass lesion in the lung.
Why investigate using chest CT?
Most useful imaging modality. Helps establish diagnosis; shows the exact location, severity and associated pathology (e.g. malignancy or intravascular thrombosis).
May show full or partial obstruction; development of collateral vessels; shows location and pathology.
Done with IV contrast.
When is chest MRI done instead of chest CT?
Useful in patients with a history of contrast allergy or those at risk of contrast induced worsening of renal function.
Briefly describe the acute treatment of SVCO
Airway should be secured by intubation or surgicall first (if appropriate).
Most common cause of SVCO is malignancy, which usually present with a gradual onset.
Urgent treatment with radiotherapy and corticosteroids should be used only for life-threatening situations.
Alternatively, percutaneous endovascular stenting can be used in patients with severe symptoms such as respiratory distress.
What corticosteroid is given to treat SVCO?
What is the dose?
Oral dexamethasone 8mg BD.
If corticosteroids are given, what also needs to be prescribed in conjunction with them?
Appropraite gastroprotection (e.g. omeprazole oral 20mg daily or lansoprazole oral 30mg once daily).
What vein is used for percutaneous endovascular stenting?
Femoral vein.
