Oncology Complications: Spinal Cord Compression, SVC Syndrome, Hypercalcaemia, TLS

Oncology Complications: Spinal Cord Compression, SVC Syndrome, Hypercalcaemia, TLS

A high-density, practical guide for nurses, medical students, and clinicians.

What Is This?

This guide covers four oncologic emergencies—spinal cord compression (SCC), superior vena cava (SVC) syndrome, hypercalcaemia of malignancy, and tumour lysis syndrome (TLS)—that require immediate recognition and intervention to prevent permanent disability or death.

Why it matters today: - 1 in 5 cancer patients develop one of these complications. - Delays in treatment lead to irreversible neurological damage (SCC), airway obstruction (SVC syndrome), renal failure (TLS), or cardiac arrest (hypercalcaemia). - Early intervention improves survival and quality of life.

Why It Matters

Key takeaway: These are time-sensitive emergencies—minutes to hours can determine outcomes.

Core Concepts

1. Spinal Cord Compression (SCC)

• Definition: Compression of the spinal cord or cauda equina by a tumour, metastasis, or pathological fracture.
• Most common cancers: Lung, breast, prostate, myeloma, lymphoma.
• Red flags:
• Back pain (worse at night, unrelieved by rest).
• Neurological deficits (weakness, sensory loss, bladder/bowel dysfunction).
• Lhermitte’s sign (electric shock-like sensation with neck flexion).
• Pathophysiology:
• Tumour-epidural space invasion-cord compression-ischaemia-permanent damage.

2. Superior Vena Cava (SVC) Syndrome

• Definition: Obstruction of the SVC by tumour, thrombus, or external compression, leading to venous congestion.
• Most common cancers: Lung cancer (small cell), lymphoma, metastatic mediastinal tumours.
• Red flags:
• Facial/neck swelling (worse in the morning).
• Dyspnoea (orthopnoea, stridor).
• Distended neck veins (JVP > 8 cm).
• Headache, confusion (cerebral oedema).
• Pathophysiology:
• SVC obstruction-? venous pressure-oedema-airway compromise-cerebral hypoperfusion.

3. Hypercalcaemia of Malignancy

• Definition: Serum Ca²? > 2.6 mmol/L (corrected for albumin) due to paraneoplastic syndromes, bone metastases, or PTHrP secretion.
• Most common cancers: Lung (squamous), breast, myeloma, renal cell carcinoma.
• Red flags:
• "Stones, bones, groans, moans, psychiatric overtones"
  • Renal: Polyuria, polydipsia, nephrolithiasis.
  • GI: Nausea, constipation, ileus.
  • Neuro: Confusion, lethargy, coma.
  • Cardiac: Short QT, arrhythmias, bradycardia.
• Pathophysiology:
• ? Osteoclast activity (bone resorption)-? Ca²?-renal impairment-cardiac toxicity.

4. Tumour Lysis Syndrome (TLS)

• Definition: Rapid tumour cell death (spontaneous or post-chemotherapy)-release of intracellular contents-electrolyte derangements.
• Most common cancers: High-grade lymphomas (Burkitt’s), leukaemias (ALL), bulky solid tumours.
• Red flags (Cairo-Bishop criteria):
• ? Uric acid (> 476 µmol/L).
• ? Potassium (> 6.0 mmol/L).
• ? Phosphate (> 1.45 mmol/L).
• ? Calcium (< 1.75 mmol/L).
• Acute kidney injury (? creatinine).
• Pathophysiology:
• Cell lysis-? K?, PO?³?, nucleic acids-uric acid precipitation-renal tubular obstruction-AKI.

How It Works (Pathophysiology & Management)

1. Spinal Cord Compression (SCC)

Mechanism: - Epidural tumour-cord compression-venous congestion-ischaemia-oedema-permanent damage.

Management Workflow:
1. Recognise red flags (back pain + neurological deficits).
2. Urgent MRI (gold standard; CT if MRI unavailable).
3. Dexamethasone 16 mg IV bolus (reduces oedema).
4. Neurosurgery/radiotherapy consult (decompression vs. RT).
5. Pain control (opioids, neuropathic agents).

Key point: Neurological recovery depends on time to treatment—< 24 hours for best outcomes.

2. SVC Syndrome

Mechanism: - SVC obstruction-? venous pressure-oedema-airway compromise-cerebral hypoperfusion.

Management Workflow:
1. Recognise red flags (facial swelling, dyspnoea, JVP).
2. CT chest with contrast (identify obstruction).
3. Elevate head of bed (reduce cerebral oedema).
4. Dexamethasone 4-8 mg IV (if lymphoma suspected).
5. Endovascular stenting (if severe symptoms).
6. Radiotherapy/chemotherapy (definitive treatment).

Key point: Avoid supine position (worsens cerebral oedema).

3. Hypercalcaemia of Malignancy

Mechanism: - ? Bone resorption (PTHrP, cytokines)-? Ca²?-renal impairment-cardiac toxicity.

Management Workflow:
1. Recognise symptoms ("stones, bones, groans, moans").
2. Check corrected Ca²? (formula: Ca²? + 0.02 × (40 – albumin)).
3. IV fluids (0.9% NaCl 200-300 mL/hr) (dilute Ca²?, promote excretion).
4. Bisphosphonates (zoledronic acid 4 mg IV) (inhibit osteoclasts).
5. Calcitonin 4 IU/kg SC (rapid onset, short duration).
6. Dialysis (if Ca²? > 4.5 mmol/L or renal failure).

Key point: Hydration is critical—bisphosphonates take 2-4 days to work.

4. Tumour Lysis Syndrome (TLS)

Mechanism: - Cell lysis-? K?, PO?³?, uric acid-renal tubular obstruction-AKI.

Management Workflow:
1. Risk stratification (high-risk: bulky tumours, high LDH, pre-existing renal disease).
2. Prevention (high-risk patients): - IV fluids (3 L/m²/day) (maintain urine output > 100 mL/hr). - Allopurinol 300 mg PO daily (prevents uric acid formation). - Rasburicase 0.2 mg/kg IV (if uric acid > 476 µmol/L).
3. Treatment (established TLS): - IV fluids + rasburicase (if uric acid > 476 µmol/L). - Calcium gluconate (if hyperkalaemia + ECG changes). - Insulin + dextrose (shift K? intracellularly). - Dialysis (if refractory hyperkalaemia, AKI).

Key point: Rasburicase is contraindicated in G6PD deficiency (risk of haemolysis).

Hands-On / Getting Started

Prerequisites

• Knowledge: Basic oncology, electrolyte physiology, emergency medicine.
• Skills: IV cannulation, ECG interpretation, fluid management.
• Equipment: IV fluids, bisphosphonates, rasburicase, dexamethasone.

Step-by-Step Minimal Example: Managing Hypercalcaemia

Scenario: A 65-year-old with lung cancer presents with confusion, constipation, and Ca²? 3.8 mmol/L.

1. Assess severity:
2. Mild (2.6-3.0 mmol/L): Oral hydration + bisphosphonates.
3. Moderate (3.0-3.5 mmol/L): IV fluids + bisphosphonates.

4. Severe (> 3.5 mmol/L): IV fluids + bisphosphonates + calcitonin ± dialysis.

5. Correct Ca²?:

6. IV 0.9% NaCl 200-300 mL/hr (monitor for fluid overload).
7. Zoledronic acid 4 mg IV over 15 min (takes 2-4 days to work).

8. Calcitonin 4 IU/kg SC (works in 4-6 hours).

9. Monitor:

10. ECG (short QT, arrhythmias).
11. Urine output (aim for > 100 mL/hr).
12. Repeat Ca²? in 24 hours.

Expected outcome: Ca²? < 3.0 mmol/L within 48 hours.

Common Pitfalls & Mistakes

Best Practices

Spinal Cord Compression

Dexamethasone 16 mg IV immediately (even before imaging). ? MRI within 24 hours (CT if MRI unavailable). ? Neurosurgery consult for unstable patients (RT for radiosensitive tumours).

SVC Syndrome

Elevate head of bed 30-45° (reduces cerebral oedema). ? Avoid IV lines in upper extremities (worsens venous congestion). ? Endovascular stenting for severe symptoms (faster relief than RT).

Hypercalcaemia

IV fluids first (bisphosphonates take days to work). ? Monitor ECG (short QT-risk of arrhythmias). ? Avoid thiazides (worsen hypercalcaemia).

Tumour Lysis Syndrome

Prevent in high-risk patients (IV fluids + allopurinol/rasburicase). ? Monitor electrolytes q6h (K?, PO?³?, Ca²?, uric acid). ? Dialysis early (if refractory hyperkalaemia or AKI).

Tools & Frameworks

Real-World Use Cases

1. Spinal Cord Compression in Breast Cancer

Scenario: A 50-year-old woman with metastatic breast cancer presents with 2 weeks of back pain, leg weakness, and urinary incontinence. Action: - Urgent MRI-T6-T8 epidural metastasis. - Dexamethasone 16 mg IV-neurosurgery consult-decompressive laminectomy + RT. Outcome: Regains ambulation (treated within 12 hours).

2. SVC Syndrome in Lung Cancer

Scenario: A 68-year-old man with small cell lung cancer presents with facial swelling, dyspnoea, and stridor. Action: - CT chest-SVC obstruction by tumour. - Dexamethasone 8 mg IV-endovascular stenting-chemotherapy. Outcome: Symptoms resolve in 24 hours.

3. Tumour Lysis Syndrome in Burkitt’s Lymphoma

Scenario: A 25-year-old man with Burkitt’s lymphoma starts R-CHOP chemotherapy and develops oliguria, K? 7.2 mmol/L, uric acid 800 µmol/L. Action: - IV fluids + rasburicase-insulin + dextrose for hyperkalaemia-dialysis. Outcome: AKI resolves, electrolytes normalise in 48 hours.

Check Your Understanding (MCQs)

Question 1

A 60-year-old man with prostate cancer presents with back pain, leg weakness, and urinary retention. What is the most appropriate next step?

A. Oral NSAIDs and outpatient MRI B. Urgent MRI spine and IV dexamethasone C. CT chest/abdomen/pelvis D. Physical therapy referral

Correct Answer: B (Urgent MRI spine and IV dexamethasone) Explanation: This is spinal cord compression—delaying MRI or steroids risks permanent paralysis. Why the Distractors Are Tempting: - A: NSAIDs may mask symptoms but do not prevent neurological damage. - C: CT is less sensitive for cord compression than MRI. - D: Physical therapy is contraindicated in acute SCC.

Question 2

A 55-year-old woman with lung cancer presents with confusion, constipation, and Ca²? 3.8 mmol/L. Which intervention should be started first?

A. Zoledronic acid 4 mg IV B. 0.9% NaCl 200 mL/hr IV C. Calcitonin 4 IU/kg SC D. Furosemide 40 mg IV

Correct Answer: B (0.9% NaCl 200 mL/hr IV) Explanation: Hydration is the first step—bisphosphonates take 2-4 days to work. Why the Distractors Are Tempting: - A: Zoledronic acid is second-line (slow onset). - C: Calcitonin works faster but is not first-line. - D: Furosemide worsens dehydration and is not recommended in hypercalcaemia