⚡ Chapter 112: Oncological Emergencies

Tumour lysis syndrome (Cairo-Bishop criteria) · Hypercalcaemia (PTHrP-mediated) · Superior vena cava syndrome · Airway obstruction (mediastinal mass) · Hyperleucocytosis & leucostasis · Rasburicase vs allopurinol · Hydration · Leucopheresis · Stenting

🔍 Core Concepts: Oncological Emergencies

📌 Tumour Lysis Syndrome (TLS)
Cairo-Bishop: uric acid ≥8, K ≥6, PO₄ ≥6.5, Ca ≤7 (or 25% change). Clinical TLS: creatinine >1.5x ULN, arrhythmia, seizure. High-risk: Burkitt, ALL, AML. Prevention: hydration, allopurinol, rasburicase.
💧 Hypercalcaemia (>10 mg/dL)
Causes: PTHrP (solid tumours), vitamin D (lymphoma). Symptoms: constipation, polyuria, shortened QT. Treatment: NS hydration, bisphosphonates (pamidronate), calcitonin (short-term).
🩸 Hyperleucocytosis & Leucostasis
WBC >100,000 (AML, ALL). Symptoms: neurological (confusion, haemorrhage), respiratory (hypoxia). Treatment: hydration, rasburicase (prevent TLS), leukapheresis, immediate chemotherapy.
🫁 Airway Obstruction (Mediastinal Mass)
Hodgkin lymphoma, germ cell tumours. Stridor, dyspnoea. Avoid sedation/muscle relaxants. Rigid bronchoscopy, stenting, radiation, chemotherapy.
❤️ Superior Vena Cava Syndrome (SVCS)
Upper body oedema, head/neck swelling, neurological symptoms (cerebral oedema). Stenting first-line, radiation if chemo-sensitive. Tissue diagnosis before treatment if possible.
⚖️ Rasburicase vs Allopurinol
Allopurinol (xanthine oxidase inhibitor) prevents uric acid formation. Rasburicase (recombinant urate oxidase) breaks down existing uric acid. Use rasburicase for high TLS risk or established hyperuricaemia.

🩺 Stepwise Approach: Tumour Lysis Syndrome

1
Identify at-risk patients
High-risk: Burkitt lymphoma, ALL (high WBC), AML, bulky disease. Check baseline uric acid, K, PO₄, Ca, Cr.
2
Hydration (first-line prevention)
IV fluids at 1.5-2x maintenance to maintain urine output >1-2 mL/kg/h. Do NOT alkalinise urine if using rasburicase (xanthine precipitation risk).
3
Hypouricaemic therapy
Allopurinol (300-400 mg/m²/day) for moderate-risk, start 2-3 days before chemotherapy. Rasburicase (0.2 mg/kg IV daily x 3-5 days) for high-risk or established hyperuricaemia (>8 mg/dL).
4
Monitor labs (Q6-12h)
Uric acid, K, PO₄, Ca, Cr. Hyperkalaemia: calcium, insulin+glucose, albuterol, kayexalate, dialysis. Hyperphosphataemia: phosphate binders (calcium acetate), dialysis.
5
Manage clinical TLS
Renal failure: nephrology consult, RRT (dialysis) if severe oliguria, K >6.5, Ca-P product >60, severe hyperphosphataemia. Seizure/arrhythmia: ICU care.
6
Hypercalcaemia management
NS 1.5-2x maintenance, furosemide (after hydration), bisphosphonates (pamidronate 1 mg/kg), calcitonin (4 IU/kg SC q12h).