Tumor Lysis Syndrome occurs during initiation of chemotherapy, as a consequence of mass destruction of malignant cells in patients with high tumor burden blood malignancies, such as Acute Myelogenous Leukemia, Acute Lymphoblastic Leukemia, advanced aggressive Lymphomas, and nodal-heavy Chronic Lymphocytic Leukemia, among others, due to the subsequent release into the circulation of colossal amounts of intracellular contents.

Hyperuricemia is common, due to the release and breakdown of purine nucleic acids from the nuclei of cells. Hyperphosphatemia, hypocalcemia, and hyperkalemia also develop. Hypocalcemia occurs as a consequence of calcium binding with phosphorus to create massive amounts of calcium phosphate, which subsequently lodges in renal tubules with resultant azotemia, similar to the consequences of hyperuricemia. Hyperkalemia can be manifested by cardiac conduction disturbances resulting in bradycardia and ekg abnormalities such as peaked T waves, flattened P waves, prolonged PR interval, QRS prolongation, life-threatening sine wave, and cardiac arrest, in that order.

Hypocalcemia may result in muscular twitching, tetany, and recurrent and recalcitrant seizure activity, in addition to QT prolongation, cardiac irritability, arrhythmia, including Torsades, and heart failure.

Nephrotoxic drugs, chronic diuretics, NSAIDS, and Ace Inhibitors should be suspended prior to induction, if appropriate, and the patient well hydrated with IVF's prior to induction.

Allopurinol and Rasburicase can be considered prior to induction to inhibit specific points on the pathway leading to the breakdown of purines into uric acid. Purine catabolism involves the conversion of hypoxanthine to xanthine to uric acid to allantoin. Allopurinol inhibits xanthine oxidase inhibiting the production of uric acid and Rasburicase promotes uric acid mobilization into allantoin. Electrolytes and uric acid should be checked Q 6 hrs.