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# Tumour lysis syndrome

An oncological emergency: when many tumour cells die at once they release potassium, phosphate and purines that harm the kidneys and heart.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Kidneys](https://durgical.com/en/anatomy/kidney/)
- [Renal pelvis](https://durgical.com/en/anatomy/renal-pelvis/)
- [Ureters](https://durgical.com/en/anatomy/ureter/)
- [Sinoatrial (SA) node](https://durgical.com/en/anatomy/sinuatrial-node/)

## In biochemistry

- [Purine degradation and salvage: Step 6 · Urate oxidase (uricase): absent in humans](https://durgical.com/en/biochemistry/pathways/purine-degradation-and-salvage/#paso-6)
- [Lactate dehydrogenase (LDH) as a lab marker](https://durgical.com/en/biochemistry/topics/lactate-dehydrogenase-as-a-lab-marker/)
- [Xanthine oxidase](https://durgical.com/en/biochemistry/enzymes/xanthine-oxidase/)
- [Uric acid](https://durgical.com/en/biochemistry/molecules/uric-acid/)
- [Drugs acting on nucleotide metabolism](https://durgical.com/en/biochemistry/topics/drugs-acting-on-nucleotide-metabolism/)

## Why it happens

- [Local effects of tumours and cancer cachexia](https://durgical.com/en/general-pathology/local-effects-of-tumours-and-cancer-cachexia/)

## What it is

A set of metabolic disturbances (hyperuricaemia, hyperkalaemia, hyperphosphataemia and hypocalcaemia) from massive tumour cell death, usually when chemotherapy starts.

## Who gets it

It is most common in acute leukaemias with very high white counts and fast-growing lymphomas such as Burkitt lymphoma; in Colombia acute lymphoblastic leukaemia is the most common childhood cancer, so it is a well-known emergency in paediatric oncology.

## Causes

- Starting chemotherapy, radiotherapy or targeted therapy in highly sensitive tumours
- Spontaneous lysis in very fast-growing tumours

## Risk factors

- Acute leukaemia with high white count or Burkitt lymphoma
- Large tumour burden or very high LDH
- Pre-existing kidney disease, dehydration or oliguria
- High uric acid before treatment

## Pathophysiology

Destroyed tumour cells spill their contents into the blood. Potassium is released in large amounts (arrhythmias). Nucleic acids are degraded through the purine pathway to hypoxanthine, xanthine and uric acid, which precipitates in the renal tubules. Released phosphate binds calcium, forming calcium phosphate crystals in the kidney and other tissues, and free calcium falls (tetany, seizures). Crystals plus dehydration cause acute kidney injury, which in turn prevents the excretion of potassium and phosphate.

## Classification

- Laboratory tumour lysis: two or more abnormalities of uric acid, potassium, phosphate or calcium (Cairo-Bishop criteria)
- Clinical tumour lysis: in addition, acute kidney injury, arrhythmia, seizures or sudden death

## Symptoms and signs

- Nausea, vomiting and loss of appetite
- Reduced or dark urine
- Cramps, tingling and muscle spasms (tetany)
- Palpitations, fainting
- Lethargy, confusion and seizures

## Red flags

- Arrhythmias or ECG changes from hyperkalaemia
- Anuria or rapidly rising creatinine
- Seizures or tetany from hypocalcaemia

## Diagnosis

**Clinical**
A patient with a high-turnover tumour, in the days after treatment starts, with oliguria, neuromuscular symptoms or arrhythmia.

**Tests**
Serial potassium, phosphate, calcium, uric acid, creatinine and LDH; blood gases and bicarbonate; urinalysis for crystals; ECG to detect the effects of hyperkalaemia and hypocalcaemia; G6PD screening before giving rasburicase.

**Imaging**
Renal ultrasound to rule out urinary tract obstruction by the tumour.

## Treatment

**Follow-up**
Risk-based prevention: generous intravenous hydration with close monitoring of urine output and electrolytes

**Medical**
Allopurinol to slow uric acid formation in intermediate risk

**Medical**
Rasburicase (recombinant uricase) in high risk or established hyperuricaemia, if there is no G6PD deficiency

**Acute**
Urgent treatment of hyperkalaemia and symptomatic hypocalcaemia

**Procedure**
Haemodialysis for refractory hyperkalaemia, fluid overload or severe [kidney](https://durgical.com/en/anatomy/kidney/) injury

## Drugs for this condition

- [Rasburicase](https://durgical.com/en/pharmacology/rasburicase/)
- [Allopurinol](https://durgical.com/en/pharmacology/allopurinol/)

## Complications

- Acute kidney injury that may require dialysis
- Arrhythmias and sudden death
- Seizures
- Haemolysis and methaemoglobinaemia if rasburicase is given with G6PD deficiency

## Prognosis

With adequate prevention it is uncommon and usually reversible; acute kidney injury worsens the cancer prognosis.

## Prevention

- Classify the risk before starting cancer treatment
- Hydration and urate-lowering drugs from before chemotherapy in patients at risk

## Test yourself

Think of the answer, then tap the question to see it.

## Which four laboratory changes define tumour lysis?

Hyperuricaemia, hyperkalaemia, hyperphosphataemia and hypocalcaemia.

## Why does calcium fall in tumour lysis syndrome?

Released phosphate binds calcium and precipitates as calcium phosphate.

## How do allopurinol and rasburicase differ in tumour lysis?

Allopurinol prevents new uric acid from forming; rasburicase breaks down existing uric acid to the more soluble allantoin.

## What must be ruled out before giving rasburicase?

G6PD deficiency, because the H₂O₂ it produces causes haemolysis and methaemoglobinaemia.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/tumour-lysis-syndrome/)

## Related conditions

- [Hereditary xanthinuria](https://durgical.com/en/conditions/hereditary-xanthinuria/)
- [Acute kidney injury](https://durgical.com/en/conditions/acute-kidney-injury/)
- [Gout](https://durgical.com/en/conditions/gout/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Rasburicase Injection: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a610008.html) (MedlinePlus, US National Library of Medicine, 2026); [Uric acid - blood: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/003476.htm) (MedlinePlus, US National Library of Medicine, 2026); [High potassium level: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/001179.htm) (MedlinePlus, US National Library of Medicine, 2026); [Allopurinol: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a682673.html) (MedlinePlus, US National Library of Medicine, 2026).

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Source: https://durgical.com/en/conditions/tumour-lysis-syndrome/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/tumour-lysis-syndrome/