Leukemia (peds)

Background

• Most common cancer in children (33% of all malignancies)

ALL

• 3/4 of pediatric leukemias
• 5-year survival 75%-80%
• Peak incidence 3-5yr old

AML

• 1/5 of pediatric leukemias
• Worse prognosis
• More complications (more intense chemo treatment required)

Clinical Features

Bone marrow infiltration and failure

• Pallor, fatigue, easy bleeding, fever, infection
• Bone/joint pain
• Hepatomegaly or splenomegaly

Hyperleukocytosis

• Clinically significant when WBC > 200K in AML, >300K in ALL
• Cerebral circulation: headache, altered mental status, visual changes, seizure, CVA
• Pulmonary circulation: shortness of breath, hypoxemia

Differential Diagnosis

Leukemias will often involve >1 cell line; other conditions restricted to single line

• Aplastic anemia
• Iron deficiency anemia
• Viral infection (EBV, CMV, Parvo)
• Immune thrombocytopenia
• Rheumatologic diseases

Evaluation

• CBC with manual differential
  • If suggestive of leukemia also order:
    • Chemistry, Ca, Phos, Mg, Uric acid, LFT, LDH, coags, T+S, UCG (if applicable)
    • Viral titers cytomegalovirus, EBV, HIV, HBV, varicella zoster
    • CXR

Management

Transfusion

• Options
  • Irradiated: for very immunosuppressed (to prevent graft vs host)
  • Leukocyte-reduced: for patients likely to receive multiple RBC or platelets in future
  • CMV seronegative: for <1yr old, if might need bone marrow transplant in future
• Anemia
  • 10 cc/kg of pRBCs raises hemoglobin by 3 gm/dL
  • Raise hemoglobin to >8
• Thrombocytopenia
• 0.1 unit/kg results in 30-50K increase in platelet count
• Risk of spontaneous ICH is extremely low until platelets <5K
• Transfuse if:
  • Asymptomatic with platelets <10K
  • Invasive procedures require platelets >50K

Hyperleukocytosis

• Aggressive IV hydration
• Urinary alkalinization (pH 7-7.5)
• Allopurinol (for Tumor Lysis Syndrome (TLS))
• Avoid diuretics and pRBC transfusion (platelets ok)
• Give platelets if <20K
• Leukapheresis