Makindo Medical Notes

Related Subjects: |Hypercalcaemia |Neutropenic Sepsis |Pulmonary Embolism |Lung Cancer |Superior vena caval obstruction syndrome |Cerebral Metastases |Metastatic bone disease |Oncological emergencies

🚨 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.

📚 References

• NICE CKS – Lung Cancer & Emergencies
• UpToDate – SVC Obstruction