🚨 Superior vena cava (SVC) obstruction develops in 5–10% of patients with right-sided malignant intrathoracic mass lesions. ⚡ Early recognition and treatment are crucial to prevent life-threatening complications.

📖 About

Superior Vena Cava (SVC) Obstruction: Blockage of venous return from the head, neck, arms, and upper chest to the heart.
🫁 Usually due to external compression or intraluminal thrombosis.
🧑‍⚕️ Recognised as an oncological emergency in clinical practice.

🧬 Aetiology

🚫 Impedes venous return → ↑ venous pressure in upper body.
🧩 SVC has thin walls and low pressure → easily compressed by mediastinal structures.
📍 Location: lies adjacent to right upper lobe and mediastinum → vulnerable to compression by tumours.
~85% of cases = malignancy (lung cancer, lymphoma).

⚠️ Causes

Malignancy: NSCLC, SCLC, lymphoma, metastatic disease.
Thrombosis: Related to CVCs, pacemakers, or PICC lines.
Fibrosis: Mediastinal fibrosis post-infection or radiotherapy.
Vascular: Aortic aneurysm, AV fistula.
Infections: TB, syphilis, histoplasmosis.
Children: Non-Hodgkin’s lymphoma is a common cause.

🩺 Clinical Features

😶‍🌫️ Facial/neck swelling, plethora, dyspnoea, persistent cough.
🫁 Severe: stridor, wheeze, airway compromise (tracheal compression).
🧵 Dilated neck & chest wall veins (collaterals).
🙆‍♂️ Pemberton’s sign: Raising arms above head → facial congestion & cyanosis worsens.

🔬 Investigations

Bloods: FBC, U&E, LFTs, CRP, calcium, ALP.
CXR: Widened mediastinum; ± right pleural effusion (~25%).
CT Chest: Gold standard – defines site, cause, biopsy planning.
Sputum Cytology: May identify lung malignancy.
Contrast Venography: Definitive but invasive – rarely required if CT sufficient.

🧪 Pathology

🔴 Majority = malignancy (lung ca, lymphoma).
Either direct invasion or external compression of SVC wall.

💊 Management

Supportive: ABC, oxygen, elevate head, secure airway if threatened.
Steroids: May reduce swelling, esp. with lymphoma.
Radiotherapy: Treatment of choice for NSCLC.
Chemotherapy: Effective in SCLC and lymphoma.
Venous Stenting: Rapid palliation; used if recurrent or severe obstruction.
Thrombosis: Remove causative line/device, start anticoagulation.

📌 UK Exam Pearls

🚨 SVC obstruction is an oncological emergency → urgent oncology input needed.
🫁 Most common cause = lung cancer (esp. right-sided). In children → lymphoma.
🙆‍♂️ Pemberton’s sign is highly testable and a classic finding.
⚡ Stenting provides the fastest symptomatic relief, especially if airway/brain perfusion threatened.
📍 Distinguish malignant vs thrombotic cause → treatment strategy differs.

🚩 SVC Obstruction Red Flags:

🧠 Raised ICP: headache, confusion, papilloedema.
🫁 Airway compromise: stridor, severe dyspnoea.
👁️ Rapidly progressive facial/neck swelling with cyanosis.
⚡ Syncope or cardiovascular compromise.

➡️ Any red flag = emergency airway planning and urgent oncology/ITU input.

📚 References

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Superior Vena Caval Obstruction syndrome