Oncologic Emergencies in the ICU

📘 1 · Washington Manual of Critical Care

Five Emergencies That Reach the ICU

Cancer patients arrive in the ICU with time-critical, largely reversible emergencies: tumour lysis syndrome (metabolic chaos from dying tumour), febrile neutropenia (sepsis without a normal immune response), hypercalcaemia of malignancy (the commonest metabolic complication of cancer), superior vena cava obstruction, and malignant spinal cord compression. Two rules dominate: give antibiotics within the hour for the febrile neutropenic patient, and give fluids first for hypercalcaemia and TLS. Prognosis of a reversible complication should not be pre-judged by the cancer.

Summarised from the Washington Manual of Critical Care — Oncologic Emergencies.

Metabolic

Tumour lysis syndrome (K⁺, PO₄, urate ↑; Ca²⁺ ↓)
Hypercalcaemia of malignancy

Infective

Febrile neutropenia / neutropenic sepsis
The "1-hour" antibiotic emergency

Structural

SVC obstruction
Malignant spinal cord compression

📗 2 · Marino's The ICU Book, 5th Edition (2025)

Tumour Lysis — When the Tumour Kills the Kidney

Tumour lysis syndrome is the metabolic price of successful cytotoxic therapy: bulky, rapidly dividing tumours (high-grade lymphoma, acute leukaemia) disintegrate and dump their intracellular contents into the blood faster than the kidney can excrete them. Potassium threatens the heart, phosphate binds calcium and precipitates in the tubules, and uric acid crystallises in an acidic tubule — together producing hyperkalaemia, symptomatic hypocalcaemia and acute kidney injury. The battle is won by anticipation: identify the high-risk patient, hydrate hard, and lower the urate before chemotherapy.

Summarised from Marino PL. The ICU Book, 5th Ed — Tumour Lysis Syndrome.

🔬 Tumour lysis syndrome

TriggerRapid tumour cell death (chemo, steroids, or spontaneous in bulky disease)

Release of intracellular K⁺, phosphate, and nucleic acids → urate

Hyperkalaemia → arrhythmia

Hyperphosphataemia → Ca-PO₄ precipitation → hypocalcaemia

Hyperuricaemia → urate crystals in tubule

ResultAcute kidney injury + life-threatening hyperkalaemia + tetany/seizures from hypocalcaemia

📗 Marino — the two things that changed TLS management

Rasburicase (recombinant urate oxidase) converts uric acid to soluble allantoin — it drops urate within hours and has largely replaced allopurinol for established/high-risk TLS (allopurinol only prevents new urate, it does not remove what is already there).
Urine alkalinisation is no longer recommended — it promotes calcium-phosphate precipitation and is unnecessary once rasburicase is used. Aggressive isotonic hydration is the backbone.

📗 Marino — the neutropenic patient has no fever "buffer"

In neutropenia (ANC <0.5 ×10⁹/L, or <1.0 and falling), the usual signs of infection are blunted — there may be little more than a fever. Yet an untreated neutropenic infection can progress to septic shock within hours. A single fever ≥38.3 °C (or ≥38 °C sustained) in a neutropenic patient is a medical emergency demanding broad-spectrum antibiotics within the hour, before cultures return.

📋 3 · TLS · Neutropenic Sepsis · Hypercalcaemia

Evidence-Based Management

Tumour lysis syndrome — hydrate, lower urate, treat electrolytes Cairo-Bishop

Diagnose laboratory TLS by ≥2 of: urate, K⁺, phosphate high or calcium low (within 3 days before to 7 days after therapy); clinical TLS adds AKI, arrhythmia, seizure or death. Aggressive isotonic IV fluids to maintain a high urine output are the cornerstone. Rasburicase for high-risk/established TLS (avoid in G6PD deficiency — risk of haemolysis); allopurinol for prophylaxis in lower risk. Treat hyperkalaemia aggressively (see Electrolyte Emergencies); do not give calcium for asymptomatic hypocalcaemia (worsens Ca-PO₄ precipitation). Early renal replacement for refractory hyperkalaemia, hyperphosphataemia, fluid overload or oliguric AKI.

Neutropenic sepsis — antibiotics within 1 hour NICE / MASCC

Treat fever + neutropenia as sepsis until proven otherwise: take cultures and give an empirical anti-pseudomonal β-lactam (piperacillin-tazobactam, cefepime or meropenem) within 60 minutes — do not wait for the neutrophil count to be confirmed if the picture fits. Add a glycopeptide (vancomycin) only for specific indications (line infection, skin/soft-tissue, severe mucositis, MRSA risk, haemodynamic instability). Use the MASCC score to identify low-risk patients who may be suitable for oral/outpatient therapy — but the unstable or high-risk patient belongs in the ICU with the full sepsis bundle.

Hypercalcaemia of malignancy — fluids then a bisphosphonate STRONG

Volume repletion with isotonic saline is the immediate treatment (corrects the dehydration driving the calcium up and promotes calciuresis). Then give an IV bisphosphonate (zoledronic acid, or pamidronate) — the definitive agent, but it takes 2–4 days to work. Calcitonin gives a rapid but short-lived (and tachyphylactic) fall for the first 48 h. Denosumab for bisphosphonate-refractory or renal impairment. Loop diuretics only after the patient is volume-replete (and mainly for fluid overload) — routine forced diuresis is outdated. Steroids help in myeloma/lymphoma.

Don't forget the structural emergencies

Malignant spinal cord compression — back pain + neurology; give dexamethasone immediately and arrange urgent MRI of the whole spine and radiotherapy/surgery (time to treatment determines whether the patient walks again). SVC obstruction — facial/arm swelling, distended veins; rarely a true airway emergency; secure a tissue diagnosis where possible before treatment, with steroids/stenting/radiotherapy as indicated.

🇮🇳 Indian Context

India sees a high burden of haematological malignancy presenting late with bulky disease, so spontaneous and treatment-induced TLS is common — anticipate it in Burkitt lymphoma and high-count acute leukaemia and start hydration + urate-lowering early. G6PD deficiency is prevalent, so screen (or at least consider it) before rasburicase, which causes severe haemolysis in G6PD-deficient patients. Rasburicase is expensive and may be reserved for high-risk cases, with allopurinol + aggressive fluids for the rest. For neutropenic sepsis, the 1-hour antibiotic rule still applies — keep an empirical anti-pseudomonal β-lactam immediately available; be alert to local resistance patterns and to tuberculosis/fungal infection in the prolonged-neutropenic patient.

💊 4 · Drug Doses

Key Drugs Across the Oncologic Emergencies

Drug	Indication	Dose	Notes
Isotonic saline	TLS & hypercalcaemia (cornerstone)	Aggressive rehydration; titrate to brisk urine output	No routine urine alkalinisation; watch overload in oliguric AKI
Rasburicase	High-risk / established TLS	0.2 mg/kg IV daily (often a single dose suffices)	Contraindicated in G6PD deficiency (haemolysis); rapidly lowers urate
Allopurinol	TLS prophylaxis (lower risk)	100–300 mg/day PO	Prevents new urate only; does not remove existing urate
Zoledronic acid	Hypercalcaemia of malignancy	4 mg IV over 15 min	Definitive; onset 2–4 days; adjust/caution in renal impairment
Calcitonin	Hypercalcaemia — rapid bridge	4 IU/kg SC/IM 12-hourly	Rapid but transient; tachyphylaxis after ~48 h
Piperacillin-tazobactam / cefepime / meropenem	Neutropenic sepsis — within 1 h	Standard high-dose anti-pseudomonal regimen	Add vancomycin only for specific indications
Dexamethasone	Cord compression; SVCO; myeloma/lymphoma hyperCa	e.g. 8–16 mg/day (higher bolus in cord compression)	Give immediately in suspected cord compression, before imaging

🗺 5 · Clinical Flowchart

Recognising & Triaging the Oncologic Emergency

Fever + neutropenia? → antibiotics NOW

Cultures, then empirical anti-pseudomonal β-lactam within 60 minutes — resuscitate as sepsis
Do not wait for the confirmed neutrophil count if the picture fits

Screen the metabolics

K⁺, phosphate, calcium, urate, creatinine, LDH — diagnose/anticipate TLS
Corrected calcium — high (hypercalcaemia) or low (TLS)?

Fluids first for TLS & hypercalcaemia

Aggressive isotonic saline; rasburicase (check G6PD) for TLS urate; treat hyperkalaemia
Hypercalcaemia → saline then IV bisphosphonate ± calcitonin bridge

Look for structural emergencies

Back pain + neurology → dexamethasone + urgent whole-spine MRI (cord compression)
Facial/arm swelling + distended veins → SVCO — tissue diagnosis then treat

Support organs & involve oncology early

Early RRT for refractory TLS metabolics/AKI; ICU-level support as needed
Discuss goals of care with oncology — but treat reversible emergencies fully

⚠️ 6 · Common Mistakes

Common Mistakes in Oncologic Emergencies

❌ Mistake 1 — Delaying antibiotics in neutropenic fever

Every hour of delay increases mortality. Take cultures and give the empirical anti-pseudomonal β-lactam within 60 minutes — do not wait for the neutrophil count or a source.

❌ Mistake 2 — Giving rasburicase in G6PD deficiency

Rasburicase generates hydrogen peroxide and causes severe haemolysis (and methaemoglobinaemia) in G6PD-deficient patients. Screen or consider risk first, especially in Indian populations.

❌ Mistake 3 — Alkalinising urine in TLS

Alkalinisation promotes calcium-phosphate precipitation in the tubule and is no longer recommended. Aggressive isotonic hydration (± rasburicase) is the strategy.

❌ Mistake 4 — Correcting asymptomatic hypocalcaemia in TLS

Giving calcium while phosphate is high drives more calcium-phosphate deposition. Treat only symptomatic hypocalcaemia (tetany, seizures, arrhythmia).

❌ Mistake 5 — Relying on allopurinol to "treat" established TLS

Allopurinol blocks new urate formation but cannot remove urate already present. Established or high-risk TLS needs rasburicase plus hydration.

❌ Mistake 6 — Loop diuretics before volume repletion in hypercalcaemia

Furosemide in a dehydrated hypercalcaemic patient worsens the volume deficit. Rehydrate first; use loops mainly for established fluid overload.

❌ Mistake 7 — Waiting for imaging before steroids in cord compression

Give dexamethasone the moment cord compression is suspected; then arrange urgent whole-spine MRI and definitive treatment. Delay costs the ability to walk.

🎓 7 · Exam Pearls — DrNB / PDCC / IFCCM / EDIC

Exam Pearls

Q: What are the metabolic derangements of TLS?
Hyperkalaemia, hyperphosphataemia, hyperuricaemia and (secondary) hypocalcaemia — with AKI. Cairo-Bishop defines laboratory and clinical TLS.

Q: How does rasburicase differ from allopurinol?
Rasburicase (urate oxidase) destroys existing uric acid → allantoin within hours; allopurinol only prevents new urate. Rasburicase is contraindicated in G6PD deficiency.

Q: What is the antibiotic rule in neutropenic sepsis?
Empirical anti-pseudomonal β-lactam within 60 minutes of presentation, after cultures — before the count is confirmed.

Q: How is hypercalcaemia of malignancy treated?
Isotonic saline rehydration first, then an IV bisphosphonate (zoledronic acid); calcitonin as a rapid short-term bridge; denosumab if refractory/renal impairment.

Q: Why avoid urine alkalinisation in TLS?
It promotes calcium-phosphate precipitation in the tubules; with rasburicase it is also unnecessary.

Q: First step in suspected malignant cord compression?
Immediate dexamethasone, then urgent whole-spine MRI and radiotherapy/surgery — do not delay steroids for imaging.

Q: What does the MASCC score do?
Risk-stratifies febrile neutropenia; high scores identify low-risk patients potentially suitable for oral/outpatient therapy.

📚 8 · References

References

Coiffier B, Altman A, Pui CH, et al. Guidelines for the Management of Pediatric and Adult Tumor Lysis Syndrome. J Clin Oncol. 2008;26:2767–2778.
Cairo MS, Bishop M. Tumour lysis syndrome: new therapeutic strategies and classification. Br J Haematol. 2004;127:3–11.
Freifeld AG, Bow EJ, Sepkowitz KA, et al. (IDSA). Clinical Practice Guideline for the Use of Antimicrobial Agents in Neutropenic Patients with Cancer. Clin Infect Dis. 2011;52:e56–e93.
NICE. Neutropenic sepsis: prevention and management in people with cancer (CG151). 2012.
Goldner W. Cancer-Related Hypercalcemia. J Oncol Pract. 2016;12:426–432.
Marino PL. The ICU Book, 5th Edition. Oncologic Emergencies / Tumour Lysis Syndrome. Wolters Kluwer; 2025.
Washington Manual of Critical Care, 4th Edition. Kollef MH, Witt CA (eds). Oncologic Emergencies. Wolters Kluwer; 2023.