From the Guidelines
In tumor lysis syndrome (TLS), the primary electrolyte abnormalities are hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia, and the recommended labs to order include a comprehensive metabolic panel (CMP) with potassium, phosphorus, calcium, and uric acid levels, as well as creatinine, BUN, and LDH, and additional tests such as CBC, urinalysis, and ECG to monitor for cardiac complications 1.
Electrolyte Abnormalities in TLS
The electrolyte abnormalities in TLS occur due to the rapid destruction of tumor cells, which releases their intracellular contents into the bloodstream, overwhelming the kidneys' excretory capacity.
- Potassium is released from dying cells, causing hyperkalemia, which can lead to cardiac arrhythmias.
- Phosphorus release leads to hyperphosphatemia, which causes reciprocal hypocalcemia as calcium binds to excess phosphate.
- Nucleic acid breakdown produces uric acid, resulting in hyperuricemia that can cause acute kidney injury.
Laboratory Tests for TLS
To monitor for TLS, the following laboratory tests are recommended:
- Comprehensive metabolic panel (CMP) with potassium, phosphorus, calcium, and uric acid levels
- Creatinine, BUN, and LDH
- Complete blood count (CBC)
- Urinalysis
- Electrocardiogram (ECG) to monitor for cardiac complications from electrolyte disturbances These tests should be monitored frequently, especially in high-risk patients undergoing chemotherapy, such as those with high-grade lymphomas, leukemias, or bulky tumors with high proliferation rates 1.
Prevention and Management of TLS
Prevention and management of TLS involve awareness of its causes, physiologic consequences, and predisposing risk factors, as well as implementation of appropriate prophylactic measures, such as hydration and rasburicase administration 1.
- Hydration should be maintained at a rate of at least 100 ml/hour (3 mL/kg/hour in children <10 kg body weight) to prevent acute kidney injury.
- Rasburicase can be used to rapidly degrade uric acid and prevent hyperuricemia.
- Loop diuretics or mannitol may be required to maintain urine output, except in patients with concomitant obstructive uropathy or hypovolemia.
- Mild hyperphosphatemia can be treated with aluminum hydroxide, while asymptomatic hypocalcemia does not require treatment 1.
From the FDA Drug Label
Tumor Lysis Syndrome (TLS) Clinical TLS was defined by changes in at least two or more laboratory parameters for hyperuricemia, hyperkalemia, hyperphosphatemia and hypocalcemia and at least one of the following events occurring within 7 days of treatment: renal failure/injury, need for renal dialysis, and/or serum creatinine increase >1.5 ULN, arrhythmia or seizure.
The electrolyte abnormalities seen in tumor lysis syndrome include:
- Hyperuricemia: elevated uric acid levels
- Hyperkalemia: elevated potassium levels
- Hyperphosphatemia: elevated phosphate levels
- Hypocalcemia: decreased calcium levels
To monitor for these abnormalities, the following labs should be ordered:
- Uric acid levels
- Potassium levels
- Phosphate levels
- Calcium levels
- Serum creatinine levels to monitor for renal function 2
From the Research
Electrolyte Abnormalities in Tumor Lysis Syndrome
The electrolyte abnormalities associated with tumor lysis syndrome (TLS) include:
- Hyperkalemia: elevated potassium levels in the blood 3, 4, 5, 6, 7
- Hyperphosphatemia: elevated phosphate levels in the blood 3, 4, 5, 6, 7
- Hyperuricemia: elevated uric acid levels in the blood 3, 4, 5, 6, 7
- Hypocalcemia: decreased calcium levels in the blood 3, 4, 5, 6, 7
Laboratory Tests for Tumor Lysis Syndrome
To diagnose and manage TLS, the following laboratory tests should be ordered:
- Electrolyte panel to monitor potassium, phosphate, and calcium levels 3, 4, 5, 6, 7
- Uric acid level to monitor hyperuricemia 3, 4, 5, 6, 7
- Renal function tests to monitor for acute kidney injury 3, 4, 5, 6, 7
- Complete blood count to monitor for anemia and hyperleukocytosis 5
Management of Electrolyte Abnormalities
Treatment options for the electrolyte abnormalities associated with TLS include:
- Hyperkalemia: sodium polystyrene sulfonate, hypertonic glucose and insulin, loop diuretics, and bicarbonate 3
- Hyperphosphatemia: reduction of dietary phosphate intake and phosphate binders such as aluminum hydroxide and aluminum carbonate 3
- Hyperuricemia: high-dose allopurinol, urate oxidase, and rasburicase 3, 4, 5, 6, 7
- Hypocalcemia: continuous intravenous infusion of calcium gluconate 3