What is tumor lysis syndrome and what are the key preventive measures in a high‑risk child receiving chemotherapy?

• A. TLS is rapid tumor cell breakdown causing hyperkalemia, hyperphosphatemia, hyperuricemia, and hypocalcemia with possible renal failure; prevent with aggressive IV hydration, uric acid–lowering therapy (allopurinol or rasburicase), and electrolyte monitoring.
• B. TLS is a mild anemia unrelated to tumor cell breakdown; prevent with iron supplementation.
• C. TLS is a bacterial infection associated with tumor cells; prevent with antibiotics.
• D. TLS is a hypersensitivity reaction to chemotherapy agents; prevent with premedication only.

Answer: (A)

Tumor lysis syndrome happens when a lot of tumor cells break open quickly after starting chemotherapy, releasing their inner contents into the bloodstream. This flooding of potassium, phosphate, and nucleic acids leads to high potassium (hyperkalemia), high phosphate (hyperphosphatemia), high uric acid from the breakdown of nucleic acids (hyperuricemia), and then low calcium because calcium binds with phosphate. The combination can overwhelm the kidneys and cause acute kidney injury.

In a high-risk child, prevention centers on keeping the kidneys well hydrated and ready to flush out the wastes. Aggressive IV hydration helps maintain kidney perfusion and dilutes the solutes so they’re excreted more easily. Uric acid–lowering therapy is key: allopurinol slows the formation of uric acid, reducing new uric acid production, while rasburicase breaks down uric acid already present in the blood. Close monitoring of electrolytes and kidney function is essential so any rising potassium or phosphate or falling calcium can be addressed early, and fluids or medications can be adjusted to prevent or treat TLS promptly.