Superior Vena Cava Syndrome (SVCS) is a medical emergency caused by obstruction of blood flow through the superior vena cava (SVC) — the major vein that drains blood from the head, neck, upper chest, and upper limbs into the heart.

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### 🧠 Etiology (Causes):

Most common cause: - Malignancy (≈ 85%), especially:

1. Lung cancer (especially small cell)
2. Non-Hodgkin lymphoma
3. Metastatic cancers (e.g., breast, testicular)

Other causes: - Thrombosis (especially from central venous catheters or pacemaker wires) - Fibrosing mediastinitis - Aortic aneurysm or goiter compressing the SVC

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### 🩺 Clinical Features:

Symptoms result from impaired venous return from the upper body:

- Facial swelling or fullness - Neck and upper limb swelling - Distended veins on chest wall or neck - Dyspnea, cough, orthopnea - Headache, dizziness, visual disturbances - Hoarseness or dysphagia (due to local compression) - Stridor (if airway is compressed)

Symptoms may be worse when lying down.

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### 🧪 Diagnosis:

- Clinical suspicion from history and exam - Chest X-ray: may show mediastinal widening or mass - CT scan with contrast: preferred imaging to confirm compression or thrombus - MRI or venography: alternative if CT is contraindicated - Biopsy if malignancy suspected

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### 💉 Management:

Depends on underlying cause and severity:

#### 🔹 Supportive: - Elevate head of bed - Oxygen - Corticosteroids (if lymphoma suspected) - Diuretics (to reduce edema)

#### 🔹 Specific: - Radiation therapy (often first-line if malignant) - Chemotherapy (especially in chemosensitive tumors like lymphoma) - Endovascular stenting (rapid symptom relief) - Anticoagulation if thrombosis

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### ⚠️ Emergency Features: - Stridor - Laryngeal edema - Cerebral edema (confusion, decreased consciousness)

These warrant urgent intervention, potentially airway management and stenting.