11/14/24, 10\:43 AM Superior Vena Cava Obstruction (SVCO)

Superior Vena Cava Obstruction (SVCO)

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Superior vena cava obstruction (SVCO)\: caused by external pressure, malignant in
reduces venous return to the heart from the head, thorax, and upper limbs.
Common cause\: external pressure from lung cancer, a
Risk factors\: lung cancer (especially small-cell), lymphoma, metastatic disease (breast, colon, oesophageal cancer),
smoking, central venous catheter use, radiation to the mediastinum.
Symptoms\: breathlessness, visual disturbance, dizziness, headache (worse on stooping), cough, swelling of
face/neck/arms.
Clinical
lymphadenopathy, hoarse voice, stridor, cyanosis, papilloedema.
Investigations\:
Imaging\: chest X-ray (widened mediastinum, right hilar prominence), CT chest with contrast (preferred), Doppler
ultrasound.
Biopsy\: bronchoscopy or transthoracic needle aspiration if underlying malignancy is unknown.
Diagnosis\: clinical for signi
Initial treatment\:
Emergency for airway obstruction\: securing airway (intubation, surgical airway), corticosteroids, diuretics, endovascular
stenting, radiotherapy.
Symptomatic\: elevate head, loosen clothing, benzodiazepines/opioids, oxygen if needed.
Managing underlying cancer\: radiotherapy, chemotherapy, corticosteroids (for haematological malignancies), surgical
resection.
Complications\:
From SVCO\: laryngeal oedema, acute upper airway obstruction.
From stenting\: stent thrombosis, migration, vena cava dissection/perforation, infection, volume overload/acute heart
failure decompensation.
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A comprehensive topic overview

Introduction

Superior vena cava obstruction (SVCO) can occur due to external pressure, malignant in
formation within the vessel.
This obstruction causes reduced venous return to the heart from the head, thorax and upper limbs. It is essential to
recognise SVCO as it can cause life-threatening upper airway obstruction.
The most common cause is external pressure from lung cancer, a
focus on SVCO associated with malignancy.
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Aetiology

The superior vena cava (SVC) is found within the middle mediastinum and is surrounded by several important structures,
such as the trachea, right bronchus, aorta and pulmonary artery. The SVC drains blood from the head, neck and upper
extremities into the right atrium.
The SVC has thin walls, making it prone to obstruction. If the obstruction occurs gradually, collateral circulation is
recruited via the azygous, internal mammary, and long thoracic venous systems. This collateral circulation is responsible for
some of the symptoms of SVCO (e.g. oedema of the upper body and dilated neck veins).
If the obstruction occurs suddenly, there is no time for collateral circulation to establish, and the presentation can often be
life-threatening.
Most cases are due to malignancy, with lung cancer being the most common cancer associated with SVCO.

Risk factors

Risk factors for SVCO include\:
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Lung cancer\: particularly small-cell lung cancer
Lymphoma
Metastatic disease\: particularly breast cancer, colon cancer and oesophageal cancer
Smoking\: due to the increased risk of lung cancer, rather than a direct association
Central venous catheter use\: may be used in cancer patients for the administration of medication
Radiation to the mediastinum

Clinical features

History

The symptoms of SVCO patients are typically associated with increased venous pressure in the upper body. Typical
symptoms may include\:
Breathlessness
Visual disturbance
Dizziness
Headache (worse on stooping)
Cough
Swelling of the face, neck and arms
The duration of symptoms can vary depending on how rapidly obstruction of the superior vena cava occurs.

Clinical examination

Typical clinical
Localised oedema of the face, neck and upper limbs
Facial plethora
Distended neck and chest veins (non-pulsatile)
Lymphadenopathy (particularly if lymphoma is the cause)
Hoarse voice\: may be due to laryngeal oedema or the underlying malignancy
Stridor\: due to laryngeal oedema or compression
Cyanosis
Papilloedema
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Figure 1. Dilated super
Figure 2. Facial swelling in SVC obstruction due to lung cancer
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Pemberton's sign
The Pemberton manoeuvre may worsen these signs and symptoms. The patient should lift both arms until they
touch the side of the face. A positive Pemberton's sign is the presence of facial congestion, cyanosis and respiratory
distress after ~1 minute.

Investigations

In SVCO associated with malignancy, the investigations should focus on diagnosing the condition and identifying the
underlying malignancy if not already known.

Imaging

Relevant imaging investigations include\:
Chest X-ray\: may show a widening of the superior mediastinum and right hilar prominence to indicate a mediastinal
mass
CT chest with contrast\: imaging modality of choice; shows the location and severity of obstruction and may help with
identi
Doppler ultrasound\: may help to identify the presence of obstruction
Figure 3. CT chest showing a right hilar
mass compressing the SVC

Biopsy

aspiration.
If the underlying malignancy is unknown, a biopsy can be performed via bronchoscopy or transthoracic needle

Diagnosis

The diagnosis of SVCO can be made clinically for signi
be made via a chest CT with contrast.

Management

The management of SVCO will depend on the underlying cause. In SVCO related to malignancy, treatment consists of
managing symptoms and underlying cancer.

Initial treatment

Patients with airway obstruction will require emergency treatment\:
Securing the airway (endotracheal intubation, surgical airway)
Corticosteroids
Diuretics
Endovascular stenting
Radiotherapy
Symptomatic treatment for SVCO includes\:
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Elevating the head
Loosening restrictive clothing
Benzodiazepines and opioids to relieve breathlessness and agitation
Oxygen to maintain oxygen saturations if required

Managing the underlying cancer

Management of the underlying cancer may involve\:
Radiotherapy\: most cancers associated with SVCO are radiotherapy sensitive
Chemotherapy
Corticosteroids\: in the case of haematological malignancies
Surgical resection

Complications

Complications of SVCO include\:
Laryngeal oedema
Acute upper airway obstruction
Complications related to endovascular stenting include\:
Stent thrombosis
Stent migration
Superior vena cava dissection or perforation
Infection
obstruction
Volume overload/acute decompensation of heart failure\: due to the sudden increase in venous return after relief of the

References

Patient.co.uk. S u p e r i o r V e n a C a v a O b s t r u c t i o n . Published 2022. Available from [LINK]
BMJ Best Practice. S u p e r i o r V e n a C a v a S y n d r o m e . Published 2023. Available from [LINK]
Radiopaedia. S u p e r i o r V e n a C a v a O b s t r u c t i o n . Published 2023. Available from\: [LINK]
Scottish Palliative Care Guidelines. S u p e r i o r V e n a C a v a O b s t r u c t i o n . Published 2019. Available from\: [LINK]

Image references

Figure 1. EMAHkempny. Superior vena cava syndrome. License\: [CC BY-SA]
Figure 2. Herbert L. Fred, MD and Hendrik A. van Dijk. SVCcombo. License\: [CC BY]
Figure 3. James Heilman, MD. SVCCT. License\: [CC BY-SA]

Related notes

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Brain Tumours
Breast Cancer
Hypercalcaemia of Malignancy
Laryngeal Cancer
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Contents

Introduction
Aetiology
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