Superior vena cava syndrome: Venous obstruction can be due to a variety of pathologies causing venous stenosis related to intimal injury or external venous compression or causing venous thrombosis in the presence or absence of underlying venous stenosis.
Clinical classifications — The clinical presentation depends upon the time course, severity, location and extent of obstruction, and the effectiveness of any compensatory changes.
three categories: acute, subacute, and chronic
●Acute symptoms onset is 14 days or less.
●Subacute symptom onset is between 14 and 28 days.
●Chronic symptom onset is greater than 28 days.
While patients with sudden onset central venous obstruction are more likely to be symptomatic, for those with obstruction that occurs over a prolonged time course, the presentation is more variable.
Edema and pain — Symptoms are predominantly related to reduced venous outflow leading to venous congestion. Edema (upper extremity, neck, chest, face) and pain are the hallmark symptoms and are present in at least 50 percent of patients .
Edema and pain can be severe, particularly in the acute setting when there is inadequate time to develop collateral venous flow.
Patients with partial or complete obstruction of the superior vena cava (SVC; ie, SVC syndrome) frequently complain of facial swelling or head fullness, which may be worsened by bending forward or lying down, or arm swelling.
In addition, patients with SVC syndrome can develop cerebral edema, causing headache, confusion, or visual/auditory disturbances. Severe cerebral edema can lead to brainstem herniation and possibly death.
Collateral venous patterning — As the main outflow vessels become obstructed, the venous system may remodel to enhance drainage through alternative pathways if enough time is permitted.
Respiratory distress — Patients with unilateral or bilateral thrombotic TCVO can present with symptoms of pulmonary embolism (PE) with tachycardia, tachypnea, dyspnea, hypoxia, or pleuritic chest pain.
Extremity ischemia — Severe manifestations of venous outflow obstruction can reduce perfusion pressure, potentially leading to ischemia and venous gangrene, limb loss, and even death.
Among patients with SVC syndrome, abnormal chest radiograph with a widened mediastinum and pleural effusion are the most common findings.
Risk factors:
Malignancies eg. Lung carcinoma, non-Hodgkin lymphoma
Central venous devices
Arteriovenous hemodialysis access
Other causes of central venous obstruction include postradiation fibrosis, fibrosing mediastinitis, infection with nocardiosis, and the rare situation of agenesis of the superior vena cava
Reference: UpToDate
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