Oncological Emergencies in Pediatrics

Oncological Emergencies

• Can have various presentations and may be the first presentation of underlying malignancy
• Accurately assessing and recognizing these emergencies is crucial for prevention and management
• The most common etiologies for pediatric oncologic emergencies are:
  • Metabolic
  • Hematologic
  • Space occupying Lesion “Pressure”
  • Infectious & Inflammatory

Tumor Lysis Syndrome (TLS)

• Rapid breakdown of malignant cells, releasing large amounts of Nucleic acid, phosphorus, and potassium into circulation
• Can occur:
  • After chemotherapy, particularly in highly sensitive tumors
  • Spontaneously, especially in rapidly growing tumors like Burkitt lymphoma
• Complications:
  • Hyperkalemia due to release of intracellular potassium
  • Hypocalcemia as a result of calcium joining with phosphate and precipitating
  • Urate nephropathy due to accumulation of DNA breakdown byproduct
  • Ca-Phos nephropathy due to precipitation
• Lab Investigations (Cairo and Bishop classification):
  • 2 or more of the following within 3 days before or 7 days after initiation of chemotherapy:
    • Uric acid > 8 mg/dl
    • Potassium > 6 mmol/dl
    • Phosphorus > 6.5 mg/dl (more than 10 = nephropathy)
    • Corrected calcium < 7 mg/dl
    • Ionized calcium < 1.12 mg/dl
• Symptoms:
  • Acute kidney injury
  • Cardiac arrhythmia
  • Seizures and tetany
  • Paresthesias and laryngeospasm
  • Sudden death
• Risk Factors:
  • Large tumor burden and hyperleukocytosis
  • Rapidly growing malignancies
  • Intravascular volume depletion
  • Renal insufficiency
• Management:
  • Admit to PICU
  • Establish good venous access (CVC)
  • Lab monitoring
  • Consult nephrology services
  • Treat electrolyte imbalance
  • Hydration with IV fluids
  • Allopurinol and Rasburicase for hyperuricemia
  • Calcium gluconate, Sodium Bicarbonate, Insulin & Glucose, and Salbutamol for hyperkalemia
  • Avoid oral phosphate and use oral phosphate binder for hyperphosphatemia

Hypernatremia, Hyponatremia, and Hypercalcemia

• Hypernatremia:
  • Etiology: dehydration, sodium load
  • Manifestation: seizures, lethargy
  • Treatment: hydration, electrolyte replacement
• Hyponatremia:
  • Etiology: SIADH, fluids, sodium loss
  • Manifestation: seizures, lethargy
  • Treatment: restrict free water, replace sodium
• Hypercalcemia:
  • Etiology: bone resorption, ectopic parathormone, vitamin D, prostaglandins
  • Manifestation: anorexia, nausea, polyuria, prolonged PR, shortened QT interval
  • Treatment: hydration, furosemide diuresis, corticosteroids, calcitonin, bisphosphonates

Hematological Emergencies

• Hyperleukocytosis:
  • Defined as peripheral WBC > 100,000 cells/UL
  • Present at initial presentation of: ALL, AML, CML
  • Pathophysiology: leukostasis, tissue injury
  • Manifestations: hypoxia, tachypnea, CNS manifestations
  • Management: hydration, chemotherapy, blood transfusion, leukapheresis, exchange transfusion
• Neutropenia:
  • Defined as absolute neutrophil counts < 0.5 × 109/L
  • Associated with increased risk of infection
  • Management: GM-CSF
• Graft vs Host Disease:
  • Defined as hostile immune reaction made by graft against the body
  • Etiology: immunosuppression, non-irradiated blood products, bone marrow transplantation
  • Manifestations: dermatitis, diarrhea, hepatitis
  • Management: corticosteroid, cyclosporine, tarcolimus, antithymocyte globulin
• Disseminated Intravascular Coagulation (DIC):
  • Defined as abnormal excessive formation of fibrin and thrombin in blood
  • Etiology: sepsis, hypotension, tumor factors
  • Manifestations: shock, hemorrhage
  • Management: FFP, platelets, cryoprecipitate, TTT of underlying cause
• Hemorrhagic Cystitis:
  • Defined as hematuria resulting from inflammation of the bladder
  • Etiology: chemotherapy (cyclophosphamide and ifosfamide)
  • Primary Prophylaxis: hyperhydration, continuous bladder irrigation, administration of Mesna
• Extravasation:
  • Defined as leakage of chemotherapy products from blood to nearby tissue
  • Management: stop injection, aspirate residual drug, antidote, avoid applying pressure to site of swelling

Space Occupying Lesions

• Superior vena cava syndrome (SVC syndrome):
  • Etiology: large masses, compression of great vessels
  • Manifestations: swelling of face and neck, prominence of neck and chest veins, cyanosis or plethora, stridor, dyspnea, neck hyperextension, chest pain, sudden respiratory arrest
  • Management: continuous cardio-respiratory monitoring, give oxygen, adequate hydration, spontaneous breathing, avoid general anesthesia, empiric treatment may be necessary
• Spinal Cord Compression:
  • Etiology: metastasis to vertebra and extramedullary space
  • Manifestations:
    • Back pain
    • Cord above T10 symptoms
    • Conus Medullaris (T10 - L2)
    • Cauda Equina Syndrome (L2 - all way below)
  • Investigations: MRI or CT
  • Treatment: combination of analgesia, corticosteroids, radiation therapy, and surgery (decompressive laminectomy)
• Increased ICP:
  • Etiology: primary or metastatic brain tumor
  • Manifestations:
    • Headache
    • Projectile vomiting
    • Blurring of vision and Papilledema
    • Seizure
    • Confusion and coma
    • Hypertension and bradycardia
    • Hydrocephalus
    • Cranial nerve III& V palsies
  • TTT: CT or MRI, Phenytoin and corticosteroids, ventriculostomy tube, radiotherapy and chemotherapy