Leukostasis and hyperleukocytosis

Background

• Hyperleukocytosis is lab abnormality of WBC >50-100K
• Leukostasis is symptomatic hyperleukocytosis; it is a medical emergency
  • Most commonly seen in pts w/ AML or CML in blast crisis
  • High blast cell count > WBC plugs in microvasculature
    • Brain and lung are most commonly affected
• 20-40% of pts w/ leukostasis die within 1st week of presentation

Clinical Features

1. Fever
   1. 80% of pts
   2. May be due to inflammation associated w/ leukostasis or concurrent infection
2. Brain Leukostasis
   1. Headache
   2. Dizziness
   3. Tinnitus
   4. Visual disturbances
   5. Ataxia
   6. Confusion
   7. Stupor
   8. Coma
   9. Sudden death
3. Pulmonary Leukostasis
   1. Respiratory distress
   2. Hypoxemia
      1. ABG may show falsely decreased PaO2; pulse oximetry is more accurate
   3. Respiratory failure

Diagnosis

• High degree of suspicion needed to make the diagnosis
• WBC count usually >100K; can have symptoms w/ WBC as low as 50K
• CXR
  • Interstial or alveolar infiltrates

Differential Diagnosis

Oncologic Emergencies

Related to Local Tumor Effects

• Malignant airway obstruction
• Bone metastases and pathologic fractures
• Malignant spinal cord compression
• Malignant Pericardial Effusion and Tamponade
• Superior vena cava syndrome

Related to Biochemical Derangement

• Hypercalcemia of malignancy
• Hyponatremia due to SIADH
• Adrenal insufficiency
• Tumor lysis syndrome
• Carcinoid syndrome

Related to Hematologic Derangement

• Neutropenic fever
  • Neutropenic enterocolitis (typhlitis)
• Leukostasis and hyperleukocytosis
• Hyperviscosity syndrome
• Thromboembolism

Related to Therapy

• Chemotherapy-induced nausea and vomiting
• Cytokine release syndrome
• Chemotherapeutic drug extravasation
• Differentiation syndrome (retinoic acid syndrome) in APML
• Stem cell transplant complications
• Catheter-related complications
  • Tunnel infection
  • Exit site infection
  • CVC obstruction (intraluminal or catheter tip thrombosis)
  • Catheter-related venous thrombosis
  • Fracture of catheter lumen
  • Oncologic therapy related adverse events

Work-Up

1. CBC
2. DIC labs
   1. DIC occurs in up to 40% of pts
   2. FDP, d-dimer, fibrinogen, coags
3. Tumor Lysis Syndrome labs
   1. TLS occurs in up to 10% of pts
   2. Chemistry
   3. Uric acid
   4. Calcium
   5. Phosphate

Treatment

1. Hyperleukocytosis (asymptomatic)
   1. Hydoxyurea may be all that is required
2. Leukostasis
   1. IV hydration
      1. Prevent dehydration which can worsen condition
   2. Chemotherapy
      1. Only treatment proven to improve survival
   3. Hydroxyurea + leukapheresis
      1. Can be use for cytoreduction if chemo will be delayed

Disposition

• Admit to ICU

Source

• Uptodate