Which electrolyte imbalance is commonly associated with tumor lysis syndrome?

Tumor lysis syndrome (TLS) is a serious condition that occurs when a large number of cancer cells die within a short period, often after chemotherapy treatment. This rapid cell lysis releases a variety of intracellular electrolytes into the bloodstream, leading to various disturbances.

Hypocalcemia, or low calcium levels, is commonly associated with TLS due to the increased levels of phosphate released during cell breakdown. When phosphate levels rise, they can lead to precipitation of calcium phosphate in tissues, which effectively reduces the amount of calcium in the serum and results in hypocalcemia. This shift is particularly important to monitor, as it can lead to symptoms such as muscle cramps, tetany, cardiac conduction abnormalities, and seizures.

The other electrolyte imbalances mentioned, such as hypokalemia, hyponatremia, and hyperchloremia, are less commonly or not typically associated with tumor lysis syndrome to the same extent. While potassium levels may increase due to cell lysis (not decrease, as would be seen in hypokalemia), sodium and chloride changes do not play a significant role in the rapid consequences of tumor lysis. Therefore, hypocalcemia is recognized as the hallmark electrolyte imbalance associated with this syndrome, making it the correct answer.