Chapter 85: Hematologic-Oncologic Emergencies in Children

INTRODUCTION

Childhood cancer is a leading cause of death in children, but with improvements in management and outcomes, many patients with new, active, or treated malignancies present to the ED. This chapter covers the most common pediatric malignancies and hematologic issues. More information on malignancy-related complications is provided in Chapter 139 and hemophilia and Von Willebrand's disease are discussed in detail in Chapter 135.

CHILDHOOD LEUKEMIA

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy, with a peak incidence between 3 to 5 years of age and a 75% to 80% 5-year survival.

Clinical Features

Patients can present with systemic complaints (fever, weight loss) or any of the following signs or symptoms of bone marrow or extramedullary infiltration: pallor, fatigue, easy bruising or bleeding, fever, or bone pain (particularly nocturnal). Many have hepatomegaly or splenomegaly. Rarely, acute myelogenous leukemia (AML) can present with gingival hyperplasia or subcutaneous masses (chloromas).

Diagnosis and Differential

The complete blood count (CBC) with manual differential is the most useful test, though leukocytosis and blasts may be absent early in the disease process, requiring close follow-up of patients with insidious complaints such as bone pain. White blood cell (WBC) counts below 4000/mL³, mild anemia, and mild thrombocytopenia should raise suspicion in these cases. Abnormalities of two or more cell lines make leukemia more likely. If the CBC is concerning for acute leukemia, obtain a chest radiograph (for mediastinal mass); electrolytes with creatinine, calcium, uric acid, and phosphate (for evidence of tumor lysis); liver function tests and lactate dehydrogenase, prothrombin time (PT)/partial prothrombin tine (PTT) (looking for disseminated intravascular coagulation); peripheral smear; type and screen if anemic; and blood and urine cultures if febrile.

The differential diagnosis is extensive depending on the patient's presenting symptom. Aplastic anemia and viral infections can cause bone marrow suppression; rheumatologic diseases can overlap with symptoms and findings of leukemia; and idiopathic immune thrombocytopenia can be difficult to differentiate, though classically involves isolated destruction of the platelets without affecting other cell lines.

Emergency Department Care and Disposition

Chemotherapy need not be initiated immediately in most cases. ED care is directed at potential complications and symptoms.

1. Anemia

   1. Irradiated, leukodepleted packed red blood cells (PRBCs) (10 mL/kg) for life-threatening hemorrhage or hemolysis. This will raise hemoglobin (Hb) 2-3 g/dL.

   2. If no hemorrhage or hemolysis, nonemergent transfusions can be given. The clinical picture should determine need for ED transfusions, with a goal hemoglobin (Hb) of >8 to 10 g/dL. This should be done in coordination with an oncologist. A lower Hb should be maintained in hyperleukocytosis if the patient can tolerate this.

2. Thrombocytopenia

   1. Platelets (10 mL/kg) for life-threatening hemorrhage, consumption, or urgent need for invasive procedure (e.g., lumbar puncture). Invasive procedures require platelet count >50,000/mm³...