Tumor Lysis Syndrome Management

Introduction to Urinary Alkalinization

The American Society of Clinical Oncology recommends against the use of urinary alkalinization for the prevention or treatment of tumor lysis syndrome due to lack of clear evidence demonstrating benefit and potential complications including calcium phosphate precipitation 1, 2, 3

Historically, sodium bicarbonate was recommended as part of TLS prevention and management strategies, particularly when using allopurinol, but this practice is no longer supported by evidence 1, 2
The solubility of uric acid increases from approximately 15 mg/dL at pH 5.0 to approximately 200 mg/dL at pH 7.0, which was the original rationale for alkalinization 3
Despite increasing uric acid solubility, alkalinization does not substantially increase the solubility of xanthine and hypoxanthine, which can be problematic in patients treated with allopurinol 4

Animal studies have shown that increasing urine flow rate is more effective than alkalinization for preventing urate-induced obstructive uropathy 1
In the absence of increased urine output, increasing urinary pH greater than 7.0 was ineffective in preventing uric acid crystallization 3
Potential complications of alkalinization include metabolic alkalosis 5, calcium phosphate precipitation 6, and xanthine-obstructive uropathies in patients treated with allopurinol 2

Aggressive hydration and diuresis are the fundamental strategies for TLS prevention and management 1, 4
Pediatric patients should receive 2-3 L/m²/day of IV fluids, typically one-quarter normal saline/5% dextrose 6
Maintain urine output within 80-100 mL/m²/h 6
Diuretics may be used to maintain adequate output if there is no evidence of acute obstructive uropathy or hypovolemia 4
For hyperuricemia management, allopurinol (xanthine oxidase inhibitor) is recommended for intermediate-risk patients 5

Urine-specific gravity should be monitored and maintained at 1.010 6
Regular assessment of serum electrolytes, particularly potassium, phosphate, and calcium 5
Monitor urine pH, but do not target alkalinization unless specifically indicated 5
Monitor fluid balance and renal function closely 6