Oncologic Emergencies: Metabolic + Treatment Effects

Cancer-related metabolic emergencies often present with vague symptoms but carry immediate renal, neurologic, and hemodynamic risk. Hypercalcemia in malignancy is usually a euvolemic process rather than simple dehydration, and treatment complications like febrile neutropenia and tumor lysis syndrome demand early recognition in the ED.

Metabolic complications of malignancy

• Cancer hypercalcemia physiology: Malignancy-associated hypercalcemia is usually driven by PTHrP, osteoclast activation, or vitamin D analog production, and these patients are often euvolemic rather than volume depleted.
• Vague symptom pattern: Lethargy, confusion, anorexia, headache, and fatigue are recurring clues across oncologic metabolic emergencies, with severity often tracking the speed of the underlying derangement.
• Hydration as first move: Isotonic IV fluids are the ED mainstay for hypercalcemia, hyperviscosity syndrome, and tumor lysis syndrome because dilution and renal perfusion buy time before disease-specific therapy.
• Hyperviscosity red flags: Hyperviscosity should be suspected with altered mental status, headache, thrombosis, or abdominal pain in leukemia or polycythemia, especially when rouleaux or extreme counts appear.
• Serum viscosity clue: A serum viscosity above 4 strongly supports hyperviscosity syndrome, although routine lab testing may be technically difficult. We get into the practical bedside clues in the episode.
• Cancer-associated thrombosis: Venous thromboembolism affects roughly 15% of patients with cancer and remains a leading cause of death; low-molecular-weight heparin is the preferred initial anticoagulant.

Complications from cancer treatment

• Febrile neutropenia definition: Febrile neutropenia pairs fever with an ANC below 1000 cells/mm3, with severe neutropenia below 500, and localizing symptoms may be absent because inflammation is blunted.
• Empiric sepsis approach: Management starts with pan-cultures, including indwelling lines, a careful source search, and prompt broad-spectrum antibiotics because delay is dangerous even when the exam looks quiet.
• Tumor lysis signature: Tumor lysis syndrome classically causes hyperuricemia, hyperkalemia, hyperphosphatemia, and hypocalcemia after rapid cytolysis, with renal failure, seizures, or dysrhythmias as the major threats.
• TLS emergency treatment: Aggressive IV hydration anchors ED care for tumor lysis syndrome, alongside standard hyperkalemia treatment and dialysis when needed. We walk through the escalation points in the chapter.
• Biologic therapy reactions: Monoclonal antibodies and immune checkpoint therapies can trigger cytokine release syndrome, a presentation that may mimic anaphylaxis with fever, hypotension, tachycardia, and myalgias.
• Supportive care priorities: Initial treatment of biologic-therapy complications is severity-based supportive care with IV fluids, circulatory support, and antibiotics when infection remains on the table.

References:

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