tumor itself This complication is more common if patients are also taking calcium supplements or calcium-containing medications such as antacids If asymptomatic, hypercalcemia does not always require intervention When present, symptoms may include nausea/vomiting, constipation, altered mental status, and renal failure Management in these cases is similar to strategies to address hypercalcemia outside of the oncology setting (see Chapters 89 Endocrine Emergencies and 100 Renal and Electrolyte Emergencies ) However, steroids should be avoided in patients with known or suspected leukemia or lymphoma Control of the underlying malignancy is the best way to address the hypercalcemia SIADH can develop as a result of some cancers themselves, particularly those involving the lungs or CNS, or from treatment with vincristine and cyclophosphamide Management of this complication hinges on fluid restriction and does not differ from that of SIADH developing in other settings (see Chapter 100 Renal and Electrolyte Emergencies ) PAIN Goals of Treatment Pain is a true emergency The relief of pain is a critical element of caring for children with cancer, and should be addressed even in patients who present to the ED for other concerns CLINICAL PEARLS AND PITFALLS NSAIDs and aspirin are generally avoided due to their antiplatelet activity Cancer patients are frequently not opioid naïve and may require higher starting doses than are standard Current Evidence Unfortunately, pain is a common symptom in oncology patients with data showing that more than 30% of pediatric cancer patients have experienced pain in the previous week When pain leads to visits to the ED, it requires careful and immediate management Severe pain is a true emergency in and of itself, and also may be particularly upsetting for cancer patients who may have already confronted significant pain as part of their cancer diagnosis, who may anticipate or fear future pain, and who may worry (usually needlessly) that their pain is a sign of progressive cancer In some cases, pain may be related to the tumor itself and therefore often will respond to chemotherapy or other cancer-directed therapies Tumors can cause