Hyperphosphatemia can result from massive cellular lysis that releases intracellular phosphate in which of the following conditions?

Hyperphosphatemia can result from massive cellular lysis that releases intracellular phosphate in which of the following conditions?

• A. Chemotherapy
• B. Acute pancreatitis
• C. Renal failure
• D. Rhabdomyolysis

Answer: (A)

Massive cellular lysis releases intracellular phosphate into the bloodstream, and the most classic setting for this rapid phosphate surge is tumor lysis syndrome after cytotoxic chemotherapy. When large numbers of malignant cells are destroyed quickly, they dump phosphate (along with potassium and nucleic acids) into circulation. The sudden rise in phosphate can overwhelm renal excretion and bind calcium, leading to hyperphosphatemia and often hypocalcemia, with potential kidney injury from calcium-phosphate precipitation. In other conditions, the mechanism differs. Pancreatitis tends to cause hypocalcemia due to fat saponification rather than a primary phosphate surge. Renal failure raises phosphate mainly by reduced excretion rather than by massive cellular release. Rhabdomyolysis can also release intracellular phosphate from damaged muscle, but the textbook scenario that best illustrates hyperphosphatemia from widespread cellular lysis is tumor lysis syndrome following chemotherapy.

Massive cellular lysis releases intracellular phosphate into the bloodstream, and the most classic setting for this rapid phosphate surge is tumor lysis syndrome after cytotoxic chemotherapy. When large numbers of malignant cells are destroyed quickly, they dump phosphate (along with potassium and nucleic acids) into circulation. The sudden rise in phosphate can overwhelm renal excretion and bind calcium, leading to hyperphosphatemia and often hypocalcemia, with potential kidney injury from calcium-phosphate precipitation.

In other conditions, the mechanism differs. Pancreatitis tends to cause hypocalcemia due to fat saponification rather than a primary phosphate surge. Renal failure raises phosphate mainly by reduced excretion rather than by massive cellular release. Rhabdomyolysis can also release intracellular phosphate from damaged muscle, but the textbook scenario that best illustrates hyperphosphatemia from widespread cellular lysis is tumor lysis syndrome following chemotherapy.