From the Guidelines
In tumor lysis syndrome (TLS), I would expect hypocalcemia and hyperkalemia (not hypokalemia), hyperphosphatemia (not hypophosphatemia), and hyperuricemia (not hypouricemia). TLS occurs when large numbers of cancer cells die rapidly, releasing their intracellular contents into the bloodstream, as described in the guidelines for the management of pediatric and adult tumor lysis syndrome: an evidence-based review 1. This massive cell death causes potassium, phosphate, and nucleic acids (which convert to uric acid) to flood the circulation. The high phosphate levels bind to calcium, causing serum calcium levels to drop (hypocalcemia).
These metabolic derangements can lead to serious complications, including:
- Cardiac arrhythmias from hyperkalemia
- Acute kidney injury from uric acid crystal formation
- Neuromuscular symptoms from hypocalcemia
Treatment focuses on aggressive hydration, allopurinol or rasburicase to manage uric acid levels, and sometimes dialysis in severe cases, as recommended by the consensus conference on the management of tumor lysis syndrome 1. Electrolyte abnormalities are corrected as needed, with particular attention to hyperkalemia which can be life-threatening. According to the recommendations, hydration and rasburicase should be administered to adult cancer patients who are candidates for tumor-specific therapy and who carry a high risk of tumor lysis syndrome 1.
In terms of specific management, mild hyperphosphatemia (< 1.62 mmol/L) does not require treatment or can be treated with aluminum hydroxide, and asymptomatic hypocalcemia does not require treatment, but symptomatic hypocalcemia can be treated with calcium gluconate 1. Mild asymptomatic hyperkalemia can be corrected with hydration, loop diuretics, and sodium polystirene, while more severe hyperkalemia requires rapid insulin plus glucose, calcium carbonate, and sodium bicarbonate, along with careful ECG monitoring 1.
From the FDA Drug Label
- 4 Pediatric Use The safety and effectiveness of Elitek have been established in pediatric patients ages 1 month to 17 years for initial management of plasma uric acid levels in patients with leukemia, lymphoma, and solid tumor malignancies who are receiving anticancer therapy expected to result in tumor lysis and subsequent elevation of plasma uric acid
- 1 Mechanism of Action In humans, uric acid is the final step in the catabolic pathway of purines. Rasburicase catalyzes enzymatic oxidation of poorly soluble uric acid into an inactive and more soluble metabolite (allantoin). 10 OVERDOSAGE Of the six reported cases of overdosage, five cases had no adverse events reported; nonserious adverse events in the sixth case (a single dose of 1. 3 mg/kg) included decreased levels of blood potassium and blood albumin, and increased levels of carbon dioxide, blood lactate dehydrogenase, blood urea, blood phosphorus, blood sodium, and blood alkaline phosphatase.
The expected metabolic derangements in tumor lysis syndrome are:
- Hyperuricemia (elevated uric acid levels)
- Hyperphosphatemia (elevated phosphorus levels)
- Hypocalcemia (decreased calcium levels)
- Hyperkalemia (elevated potassium levels)
Note that the options Hypokalemia, Hypophosphatemia, and Hypouricemia are not expected in tumor lysis syndrome. 2
From the Research
Metabolic Derangements in Tumor Lysis Syndrome
The expected metabolic derangements in tumor lysis syndrome include:
- Hyperuricemia
- Hyperphosphatemia
- Hyperkalemia
- Hypocalcemia
These derangements are characterized by an elevation in uric acid, phosphate, and potassium levels, and a decrease in calcium levels, as noted in studies 3, 4, 5, 6, 7.
Specific Derangements
In the context of the provided options:
- Hypocalcemia is expected, as it is a characteristic finding in tumor lysis syndrome 3, 4, 5, 6, 7.
- Hypokalemia is not expected, as hyperkalemia is a common derangement in tumor lysis syndrome 3, 4, 5, 6, 7.
- Hypophosphatemia is not expected, as hyperphosphatemia is a characteristic finding in tumor lysis syndrome 3, 4, 5, 6, 7.
- Hypouricemia is not expected, as hyperuricemia is a cardinal sign of tumor lysis syndrome 3, 4, 5, 6, 7.