Oncologic Emergencies

Introduction

• Here I list key hematologic emergencies that show up on the royal college exam;

Tumor Lysis Syndrome

Leukostasis

• Extremely elevated blast cell count and markers of tissue malperfusion
  • Large numbers of WBCs obstruct microcirculation
• Extremely high mortality (20-40% at 1 week), requires prompt management. 
• Most commonly seen in AML or CML blast crisis
• Typical Malignancies:
  • AML (most common - large non-deformable blasts)
  • ALL 
  • NOTE: CLL extremely uncommon unless WBC > 400
  • NOTE: CML extremely uncommon unless myeloid blast crisis and WBC > 250 
• Presentation:
  • Patients with leukemia & hyperleukocytosis presents with respiratory or neurologic distress
  •  
• Labs:
  • Total leukemic blood count > 50 * 10^9 /L 
  • Thrombocytosis (Blast fragments mistakenly counted as plts)
  • Hyperkalemia (spurious)
  • DIC – decreased fibrinogen, increased D-Dimers
  • Spontaneous TLS – High Uric Acid, High K+, High PO4 + LOW Ca++
• Management
  • Cytoreduction
    • Chemotherapy (i.e. hydroxyurea, but induction chemotherapy preferred)
    • Leukapheresis
  • TLS Prophylaxis
    • Hydration, Allopurinol
  • DIC Monitoring
  • Thrombocytopenia
    • Treat to maintain plts > 20,000-30,000
    • Avoid Transfusion (can increase blood viscosity)