Serious metabolic disorder caused by the rapid death of tumour cells in response to chemotherapy; this results in a massive release of intracellular contents into the bloodstream, leading to significant electrolyte imbalances

Aetiology

• Most commonly associated with aggressive, rapidly proliferating tumours such as acute leukaemia and high-grade lymphomas, particularly after the initiation of cytotoxic therapy
• The syndrome occurs due to the rapid release of intracellular contents from dying tumour cells following chemotherapy
  • This leads to hyperuricaemia, hyperphosphatemia, hyperkalaemia, and hypocalcaemia

Clinical features

Patients may present with symptoms related to the electrolyte abnormalities, which include:

• Dysuria or oliguria
• Abdominal pain
• Weakness
• Nausea or vomiting
• Muscle cramps
• Seizures
• Cardiac arrhythmias

Investigations

• U&E: potassium and phosphate are usually raised
• Calcium: typically low in tumour lysis syndrome
• Uric acid: usually elevated
• ECG: to identify any metabolic abnormalities such as hyperkalaemia that may precipitate life-threatening arrhythmias

Management

• Correction of electrolyte imbalances:
  • Cardiac arrhythmia and hyperkalaemia → calcium gluconate
  • Consider dialysis for electrolyte abnormalities resistant to medical management
  • Allopurinol or rasburicase may be administered to prevent or treat hyperuricaemia