Management Patients who present with signs of CRS may be indistinguishable from patients with sepsis and concurrent treatment for presumed sepsis including administration of broad-spectrum antibiotics is important For mild symptoms, supportive care may be sufficient For patients with severe symptoms, evidence of organ dysfunction, or life-threatening illness, the addition of glucocorticoids and/or tocilizumab (an anti– IL-6 monoclonal antibody) may be indicated, in consultation with an oncologist All of these patients should be admitted and many will require a critical care setting METABOLIC COMPLICATIONS OF CANCER TREATMENT Complications affecting metabolic balance and the endocrinologic system are common in children with cancer These may be because of the neoplastic disease itself, as has been addressed in the sections on newly diagnosed cancer, or due to complications from cancer therapy TLS is probably the most noteworthy example of metabolic derangement in the setting of cancer (see “Leukemia” section) TLS can be present at the time of diagnosis or develop as chemotherapy is initiated and tumor cells begin to die in response Prevention of tumor lysis relies on protecting the function of the kidneys while preventing severe metabolic derangements ( Table 98.3 ) Hyperhydration should be initiated to achieve brisk, dilute urine output In addition to IV hydration, all patients should receive therapy with either allopurinol (10 mg/kg/day with maximum dose 300 mg) or rasburicase Allopurinol is a xanthine oxidase inhibitor that impairs the production of uric acid Rasburicase, a recombinant urate-oxidase enzyme, causes direct lysis of uric acid and leads to a rapid drop in uric acid levels The usual starting dose is 0.2 mg/kg IV Rasburicase is indicated in patients who are at higher risk of TLS complications such as patients with compromised renal function or an extremely elevated uric acid level, who have advanced Burkitt lymphoma, who cannot tolerate hydration (e.g., CNS hemorrhage or pre-existing cardiac dysfunction), or whose uric acid is rising despite allopurinol Rasburicase is contraindicated in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency as it can result in oxidative stress and hemolysis Use of alkalinized intravenous fluids is becoming less common as its efficacy is uncertain If using rasburicase, hydration with alkalinization is unnecessary Of note, not all electrolyte abnormalities in the setting of TLS should be corrected ( Table 98.3 ) Hyperphosphatemia can be treated using aluminum hydroxide as frequently as every to hours Hypophosphatemia should not be corrected unless it is in a critically low range (less than mEq/L) Serum potassium levels must be aggressively monitored Hyperkalemia in the setting of TLS should be managed as it would be in other disease states (see Chapter 100 Renal and Electrolyte Emergencies ) with Kayexalate, insulin and glucose, and dialysis, if needed Hypokalemia should