Tumour Lysis Syndrome (TLS)

An oncological emergency caused by massive breakdown of malignant cells (spontaneously or after chemotherapy), leading to release of intracellular contents into the bloodstream.

Biochemical Triad 

1. Hyperkalaemia: due to release of intracellular potassium. → Causes arrhythmias, muscle weakness.
2. Hyperphosphataemia: due to release of phosphate.
3. Hypocalcaemia: phosphate binds calcium → precipitates in tissues → neuromuscular irritability, tetany, seizures.
4. Hyperuricaemia: purine breakdown → uric acid crystallises in renal tubules → acute kidney injury.

Causes / Risk Factors:

i. High-grade haematological malignancies (e.g. ALL, AML, Burkitt lymphoma).
ii. Large tumour burden.
iii. First few days of chemotherapy (induction phase).
iv. Can rarely occur spontaneously.

Clinical Features:

i. Nausea, vomiting, diarrhoea.
ii. Confusion, seizures (from electrolyte disturbances).
iii. Arrhythmias (hyperkalaemia, hypocalcaemia).
iv. Oliguria or anuria → acute kidney injury.

Investigations:

. Bloods: ↑ K, ↑ phosphate, ↓ calcium, ↑ uric acid, ↑ creatinine.
. ECG: Hyperkalaemia changes (peaked T-waves, arrhythmias).

Management:

Prevention is key in high-risk patients:

. Vigorous IV hydration before and during chemotherapy.
. Allopurinol or rasburicase (urate-lowering agents).

If TLS develops:

. Continue IV fluids (maintain urine output).
. Correct electrolytes (e.g. calcium gluconate for hypocalcaemia if symptomatic, insulin/dextrose for hyperkalaemia).
. Dialysis if refractory renal failure or life-threatening electrolyte imbalance.