Tumor Lysis Syndrome

Definition

Oncologic emergency due to tumor lysis with release of intracellular potassium, phosphate, and nucleic acids (source of uric acid) into the bloodstream
Uric acid can precipitate in the kidneys leading to renal failure
Hyperphosphatemia can lead to calcium phosphate deposition, which can lead to both hypocalcemia and acute kidney injury

Figure 1: Tumor Lysis Syndrome Overview

Generally occurs with a high tumor burden and with initiation of cytotoxic therapy (i.e. induction chemotherapy)
Can also occur spontaneously with high tumor burden (i.e. hyperleukocytosis)
The risk of developing tumor lysis syndrome (TLS) varies with the type of leukemia/lymphoma:
- Extremely high risk: Burkitt Lympoma (bulky or advanced stage)/Leukemia
- High Risk: T cell Leukemia/lymphoma, ALL with WBC >100K, AML with WBC >50K
- Intermediate Risk: Stage III/IV Non-Burkitt NHL, Burkitt lymphoma (not bulky or advanced)/Leukemia, ALL with WBC 50-100K, AML with WBC 10-50K
- Low Risk: All other patients not meeting above criteria

Monitoring of electrolytes and urine output/urine pH. Generally q6-8hr electrolytes
Hydration: Generally 2x maintenance fluids with D5 1/4 to 1/2 NS (can develop SIADH and hyponatremia). Do not add potassium to the fluids. Generally do not add bicarbonate to the fluids unless urine pH <6.5 as high urine pH can precipitate Ca-Phos deposition and uropathy
Lasix 1-2 mg/kg/dose as clinically indicated (loop diuretics can also worsen hypocalcemia)
Rasburicase when uric acid >8 mg/dL (contraindicated with G6PD deficiency as can cause hemolysis and methemoglobinemia- i.e. male African/Mediterranean/SE asian ancestry)
Allopurinol not used routinely at University of Michigan but can be utilized (along with urinary alkalinization as hypoxanthine/xanthine can accumulate and is excreted more easily with a higher urinary pH)
Urinary alkalnization NOT indicated as it can worsen Ca-Phos nephropathy and in the setting of rasburicase, hypoxanthine/xanthine excretion with allopurinol is no longer a significant concern
Hyperkalemia can be treated with judicious use of calcium (again trying to avoid a CaXPhos product of 60 or more), Lasix, Dextrose/insulin, and sodium bicarbonate. Longer term therapies include Kayexalate.
Renal replacement therapy may be necessary for prolonged hyperkalemia or uropathy related to hyperuricemia (rare now with rasburicase) or Ca-Phos deposition
Can treat hyperphosphatemia with binding agent such as sevelamer or in more refractory cases, renal replacement therapy

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2. Eur J Haematol. 2008 Apr;80(4):331-6.

3. Bone Marrow Transplant. 2006 Jun;37(11):997-1001