The document discusses Superior Vena Cava Syndrome (SVCS), which results from obstruction of blood flow through the Superior Vena Cava (SVC). SVCS was first described in 1757 and was historically caused by non-malignant processes, but malignancy is now the most common cause. The obstruction causes venous congestion and symptoms like face/neck swelling, cough, and dilated chest veins. Treatment depends on symptom severity and the underlying cause, with stenting used for life-threatening cases and management of malignancy for non-emergency cases.
2. HISTORY
First recorded description of SVC obstruction - 1757 when William Hunter described the
entity in a patient with a syphilitic aortic aneurysm.
For nearly two centuries – non-malignant processes such as aortic aneurysms, syphilitic
aortitis, or chronic mediastinitis due to tuberculosis were the predominant etiologic factors.
Subsequently, malignancy became the most common cause, accounting for 90% of cases
by the 1980s.
More recently, the incidence of SVC syndrome due to thrombosis has risen, largely because
of increased use of intravascular devices such as catheters and pacemakers.
Benign causes now account for 20 to 40 percent of cases of SVC syndrome.
3. INTRODUCTION
Superior vena cava syndrome is a collection of clinical signs and symptoms resulting
from either partial or complete obstruction of blood flow through the SVC.
This obstruction is most commonly a result of thrombus formation or tumor
infiltration of the vessel wall.
The resulting venous congestion produces a clinical scenario relating to increased
upper body venous pressures.
The most common signs and symptoms include face or neck swelling, upper
extremity swelling, dyspnea, cough, and dilated chest vein collaterals.
4. ETIOLOGY
The majority of SVC syndromes are the result of mediastinal malignancies, primary
among which is small cell bronchogenic carcinoma.
The second most commonly associated malignancy is non-Hodgkins lymphoma,
followed by metastatic tumors.
In addition, benign or nonmalignant causes of superior vena cava syndrome now
comprise at least 40% of cases.
Iatrogenic thrombus formation or SVC stenosis is a growing etiology due to pacemaker
wires and semipermanent intravascular catheters used for hemodialysis, long term
antibiotics, or chemotherapy.
6. PATHOPHYSIOLOGY
Collateral veins may arise from the azygos, internal mammary, lateral thoracic, paraspinous, and
esophageal venous systems.
The venous collaterals dilate over several weeks.
Upper body venous pressure is markedly elevated initially but decreases over time.
Symptoms and signs from SVC obstruction depends upon the rate at which complete
obstruction of the SVC occurs in relation to the recruitment of venous collaterals.
Malignant disease - symptoms of SVC syndrome within weeks to months.
Rapid tumor growth does not allow adequate time to develop collateral flow.
7. PATHOPHYSIOLOGY
In contrast, fibrosing mediastinitis due to an infection such as histoplasmosis may not become symptomatic
for years.
Edema - Narrow the lumen of the nasal passages and larynx, potentially compromising the function of the
larynx or pharynx- dyspnea, stridor, cough, hoarseness, and dysphagia.
Cerebral edema can also occur and lead to cerebral ischemia, herniation, and possibly death.
Cardiac output is diminished transiently by acute SVC obstruction.
Within a few hours, blood return is re-established by increased venous pressure and collaterals.
Hemodynamic compromise, if present, more often results from mass effect on the heart than from SVC
compression.
9. SYMPTOMS
Dyspnea
Distended veins
Edema of the face, neck, upper body
and arms
Coughing (with or without blood)
Hoarseness
Chest pain
Difficulty swallowing
Cyanosis
Horner’s syndrome, which includes
small pupil, drooping eyelid and no
sweating on one side of the face.
Paralysed vocal cord
Headache
Anxiety
Dizziness
Confusion
13. CHEST CT
Defines the level and extent of venous blockage.
Identification of the underlying cause of venous
obstruction.
Identify and map collateral pathways of venous
drainage.
Presence of collateral vessels on CT is a strong
indicator of SVC syndrome.
Specificity of 96 percent and sensitivity of 92
percent.
14. CONTRAST VENOGRAPHY
Bilateral upper extremity venography is the
gold standard for identification of SVC
obstruction and the extent of associated
thrombus formation.
Superior to CT for defining the site and extent
of SVC obstruction and for visualizing
collateral pathways.
It does not identify the cause of SVC
obstruction unless thrombosis is the sole
etiology.
15. OTHER INVESTIGATION
MR VENOGRAPHY
Magnetic resonance
venography (MRI) is an
alternative approach that may
be useful for patients with
contrast dye allergy or those
for whom venous access
cannot be obtained for
contrast enhanced studies
ULTRASOUND
Exclusion of thrombus in upper
extremity, axillary, subclavian,
and brachiocephalic veins.
HISTOLOGICAL
Histologic diagnosis is a
prerequisite for choosing
appropriate therapy for the
patient with SVC syndrome
associated with malignancy.
18. MANAGEMENT
Management of the SVC obstruction itself is dictated by the severity of the symptoms,
the likelihood of response to a particular treatment, and the treatment of the
malignancy itself.
Thus, the right approach will be influenced by the symptoms, the type and stage of
malignancy, the patient's performance status, and comorbidities.
When symptoms are life threatening (grade 4), immediate intervention is indicated and
should be directed at urgent relief of the SVC obstruction.
Intravascular stenting is safe and provides the most immediate relief.
Stenting can often be accomplished even if there is complete SVC obstruction or
thrombosis, particularly if thrombolytics are first used.
19. MANAGEMENT
If symptoms are not life threatening, the ultimate outcome and survival from SVCS is
dependent on the underlying root cause.
Therefore, patients with grade 1 and 2 and most with grade 3 symptoms should
undergo diagnostic and staging procedures to define the tumor type and stage.
Patients with lymphoma, small-cell lung cancer, and germ cell tumors should experience
a rapid clinical response from systemic chemotherapy.