15.2 Oncologic Emergencies, Acute Kidney Injury & Pediatric Electrolyte Crises

Oncologic Emergencies, Acute Kidney Injury & Electrolyte Crises

Children with cancer and children with kidney failure are transported at their most unstable moments: at diagnosis, during early chemotherapy, and during complications. Many of these emergencies are metabolic, and they interact with one another. For example, tumor lysis causes kidney injury, which worsens hyperkalemia.

Tumor Lysis Syndrome (TLS)

TLS occurs when rapidly dividing tumor cells break down, spontaneously or after treatment starts. It is most common in Burkitt lymphoma, T-cell lymphoblastic lymphoma, and leukemias with high white counts.

Prevention and treatment:

• Hydration: Commonly about 2–3 L/m²/day (roughly twice maintenance) to keep urine output high. Give no potassium in the fluids.
• Uric acid control:
  • Allopurinol prevents new uric acid formation.
  • Rasburicase breaks down existing uric acid rapidly. It is contraindicated in G6PD deficiency because it can cause hemolysis and methemoglobinemia.
• Urine alkalinization is no longer routine. It can promote calcium phosphate precipitation.
• Treat hyperkalemia as in Section 6.7. Treat symptomatic hypocalcemia cautiously, because giving calcium when phosphate is very high can cause calcium phosphate precipitation.
• Monitor electrolytes frequently, and involve nephrology early. Dialysis may be needed.
• During transport, have ECG monitoring, calcium, insulin and dextrose, and a plan for arrhythmia.

Febrile Neutropenia

• Definition: Fever in a child with an absolute neutrophil count (ANC) below 500/mcL (or expected to fall below that level). It is common after chemotherapy.
• Why it is an emergency: Neutropenic children can have little inflammatory response, so sepsis may progress to shock quickly with few localizing signs.
• Management:
  • Blood cultures from the central line (and peripherally per protocol)
  • An antipseudomonal beta-lactam (for example, cefepime or piperacillin-tazobactam) as soon as possible, usually within 60 minutes
  • Vancomycin is added for suspected catheter infection, skin or soft-tissue infection, pneumonia, or instability
  • Treat shock (Section 12.1)
• Avoid rectal temperatures and rectal medications because of mucosal injury and infection risk.
• Typhlitis (neutropenic enterocolitis) causes right lower quadrant pain, distension, and diarrhea and can perforate. Keep the child NPO, provide anaerobic coverage, and obtain surgical evaluation.

Hyperleukocytosis and Leukostasis

• Hyperleukocytosis: White count above about 100,000/mcL, most often in acute leukemia.
• Leukostasis: Sludging of leukemic blasts in small vessels, especially in the lungs and brain. It causes hypoxemia, respiratory distress, headache, confusion, stroke, and intracranial hemorrhage.
• Management:
  • Hydration
  • Tumor lysis precautions
  • Correct coagulopathy and thrombocytopenia (platelets carry little risk of raising viscosity)
  • Avoid unnecessary red cell transfusion, which raises blood viscosity. Transfuse cautiously only for clear indications.
  • Cytoreduction by oncology (chemotherapy, sometimes leukapheresis)

Other Oncologic Emergencies

• Anterior mediastinal mass and superior vena cava syndrome: Airway and anesthesia risks (Section 12.4).
• Spinal cord compression: Back pain, weakness, sensory level, bladder or bowel dysfunction. Give corticosteroids per oncology or neurosurgery, obtain urgent MRI, and preserve neurological function.
• Increased intracranial pressure from brain tumors: Section 13.2 principles apply, and ventriculoperitoneal shunts may be present.
• Hypercalcemia of malignancy (less common in children): Hydration, then calcium-lowering therapy per oncology.

Acute Kidney Injury (AKI)

AKI is staged by rising serum creatinine (for example, 1.5 times baseline or more) and/or reduced urine output (for example, below 0.5 mL/kg/h for 6 hours or more) under the KDIGO framework, with pediatric adaptations.

Hemolytic uremic syndrome (HUS)

• The classic triad is microangiopathic hemolytic anemia (schistocytes), thrombocytopenia, and AKI.
• It usually follows bloody diarrhea from Shiga toxin-producing E. coli (such as O157:H7), typically within days to about 2 weeks.
• Complications include hypertension, seizures, stroke, pancreatitis, and heart involvement.
• Management: Supportive care with careful fluids, dialysis when needed, and transfusion for severe anemia. Platelet transfusion is avoided unless bleeding or a procedure requires it. Antimotility agents are avoided in bloody diarrhea, and antibiotics are generally avoided in suspected STEC infection because of concern that they may increase toxin release.

AKI management in transport

• Restore perfusion. Then avoid fluid overload: track intake and output and calculate percent fluid overload (Section 6.7).
• Stop or adjust nephrotoxic drugs and renally cleared drug doses.
• Treat hyperkalemia, acidosis, hyponatremia, hypocalcemia, and hypertension (Section 12.4).
• Indications for urgent dialysis or renal replacement therapy include refractory hyperkalemia, severe acidosis, fluid overload with respiratory compromise, uremic complications (encephalopathy, pericarditis, bleeding), and some toxic ingestions. These indications may determine which center the child needs.

Pediatric Electrolyte and Endocrine Crises

Section 6.7 covers sodium, potassium, calcium, and magnesium disorders. Two endocrine emergencies commonly present to transport teams:

• Adrenal crisis: Children with congenital adrenal hyperplasia (salt-wasting forms present in the first weeks with vomiting, dehydration, hyponatremia, hyperkalemia, and hypoglycemia), adrenal insufficiency, or chronic steroid use who become ill.
  • Give stress-dose hydrocortisone (commonly about 50–100 mg/m², or a weight-based dose per protocol) promptly.
  • Give isotonic fluid and dextrose.
  • Treat hyperkalemia.
  • Do not wait for cortisol levels in an unstable child.
• Diabetic ketoacidosis is covered in Section 14.2. Remember potassium shifts and cerebral edema.

Transport Scenario

A 9-year-old with newly diagnosed Burkitt lymphoma and a large abdominal mass has potassium 6.4 mEq/L, phosphate 9.8 mg/dL, calcium 7.1 mg/dL, uric acid 14 mg/dL, and falling urine output. Before transport, the team:

• Starts potassium-free hydration at about 3 L/m²/day
• Gives calcium gluconate for peaked T waves after discussion with medical control
• Starts insulin and dextrose to shift potassium
• Confirms that G6PD testing was sent before rasburicase is considered

The receiving oncology and nephrology teams are told that urgent dialysis may be needed.