Rosen & Barkin's 5-Minute Emergency Medicine Consult (421 page)

FOLLOW-UP

• Newly diagnosed leukemia with:
  
  • Symptomatic anemia
    
  • WBC >30,000
    
  • Thrombocytopenia
    
• ICU admission for unstable patients with disseminated intravascular coagulation, blast crisis, or bleeding
  

Asymptomatic patients without significant lab abnormalities

Hematology for any patient presenting with new leukemia

• Monitor for tumor lysis and secondary hyperkalemia.
  
• Hyperleukocytosis may present as respiratory failure or hemorrhage.
  

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• Higdon ML, Higdon JA. Treatment of oncologic emergencies.
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• Hurley TJ, McKinnell JV, Irani MS. Hematologic malignancies in pregnancy.
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• Nazemi KJ, Malempati S. Emergency department presentation of childhood cancer.
  Emerg Med Clin North Am
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• Pui CH, Evans WE. Acute lymphoblastic leukemia.
  N Engl J Med
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• Sawyers CL. Chronic myeloid leukemia.
  N Engl J Med
  . 1999;340:1330–1340.
  
• Tsiodras S, Samonis G, Keating MJ, et al. Infection and immunity in chronic lymphocytic leukemia.
  Mayo Clin Proc
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• Zuckerman T, Ganzel C, Tallman MS, et al. How I treat hematologic emergencies in adults with acute leukemia.
  Blood
  . 2012;120(10):1993–2002.
  

See Also (Topic, Algorithm, Electronic Media Element)

Hyperviscosity Syndrome

CODES

• 204.10 Chronic lymphoid leukemia, without mention of having achieved remission
  
• 205.10 Chronic myeloid leukemia, without mention of having achieved remission
  
• 208.90 Unspecified leukemia, without mention of having achieved remission
  

BASICS

Definition:

• Any elevation of total number of white blood cells (WBCs) beyond expected value
  
• Normal range for total WBCs (/mm
  ³
  ):
  
  • Adults: 4,500–11,000
    
  • Children: WBC count decreases with age:
    
    • Infant, 1 wk old: 5,000–21,000
      
    • Toddler, 1 yr old: 6,000–17,500
      
    • Child, 4 yr old: 5,500–15,500
      
  • Pregnancy:
    
    • 1st trimester: 5,000–14,000
      
    • 2nd trimester: 5,000–15,000
      
    • 3rd trimester: 5,000–17,000
      
• Normal ranges shift upward with:
  
  • Exercise
    
  • Female gender
    
  • Smoking
    
  • Daytime hours
    
• Given wide range of normal values, numbers must be interpreted in clinical context
  
• Specific subsets
  
• Neutrophil predominance (neutrophilia):
  
  • Absolute neutrophil count >7,500/mm
    ³
    
  • Half of circulating neutrophils are adherent to blood vessel walls. They can be rapidly released (demarginate) in response to acute stressors. This can double the WBC count.
    
  • An additional pool of mature neutrophils, immature metamyelocytes, and band neutrophils are stored in the bone marrow. These can be released increasing the neutrophil count typically during inflammation or infection. Release of immature forms results in a “left shift.”
    
• Lymphocyte predominance (lymphocytosis)
  
  • Absolute lymphocyte count >4,000/mm
    ³
    
  • Stored in the spleen, lymph nodes, thymus, and bone marrow. They are typically released in response to foreign antigens or viral infections
    
• Hyperleukocytosis (WBC >100,000/mm
  ³
  ):
  
  • Seen primarily in hematologic malignancies
    
  • Associated with leukostasis which can lead to cerebral infarction, pulmonary insufficiency, death
    

• CBC most common test ordered from the emergency department
  
• Leukocytosis is one of the most commonly found lab abnormalities.
  
• Elevated WBC count can be found in 17% of ED patients in whom a CBC is checked (Callaham)
  

• Neutrophil predominance:
  
  • Demargination/stress reaction:
    
    • Stress
      
    • Exercise
      
    • Surgery
      
    • Seizures
      
    • Trauma
      
    • Hypoxia
      
    • Pain
      
    • Vomiting
      
  • Inflammation:
    
    • Rheumatoid arthritis
      
    • Gout
      
    • Inflammatory bowel disease
      
  • Infection, generally bacterial
    
  • Lab error
    
  • Labor
    
  • Leukemoid reaction (TB, Hodgkin, sepsis, metastatic CA)
    
  • Medications:
    
    • β-Agonist (epinephrine, cocaine, parenteral albuterol)
      
    • Corticosteroids
      
    • Lithium
      
    • Granulocyte colony stimulating factor
      
  • Metabolic disorders:
    
    • DKA
      
    • Thyrotoxicosis
      
    • Uremia
      
  • Malignancy, nonhematogenous
    
  • Myeloproliferative disorders:
    
    • Chronic myeloid leukemia
      
    • Polycythemia vera
      
  • Pregnancy
    
  • Rapid RBC turnover:
    
    • Hemorrhage
      
    • Hemolysis
      
  • Tissue necrosis:
    
    • Cancer
      
    • Burns
      
    • Infarction
      
• Lymphocyte predominance:
  
  • Infection, generally viral, early stages:
    
    • Mononucleosis
      
    • VZV
      
    • CMV
      
    • Viral hepatitis
      
  • Bacterial infection, specifically:
    
    • Pertussis
      
    • TB
      
    • Syphilis
      
    • Rickettsia
      
    • Babesia
      
    • Bartonella
      
  • Hypothyroidism
    
  • Immunologic responses:
    
    • Immunization
      
    • Autoimmune diseases
      
    • Graft rejection
      
  • Lymphoproliferative disease:
    
    • Acute lymphocytic leukemia
      
    • Chronic lymphocytic leukemia
      
    • Non-Hodgkin lymphoma
      
  • Splenectomy
    

DIAGNOSIS

• Depends upon presenting complaint
  
• Symptoms suggestive of infection:
  
  • Cough
    
  • Fever
    
  • Rash
    
  • GI symptoms
    
• Symptoms suggestive of long-term inflammation:
  
  • Joint pain
    
  • Rash
    
• Symptoms suggestive of malignancy:
  
  • Weight loss
    
  • Fatigue
    
  • Night sweats
    

• Focal signs of infection:
  
  • Cellulitis/abscess
    
  • Otitis
    
  • Pharyngitis
    
  • Pneumonia
    
• Signs of malignancy:
  
  • Hepatosplenomegaly
    
  • Lymphadenopathy
    
  • Pallor
    
  • Bleeding
    
• Signs of chronic inflammatory conditions:
  
  • Joint pain and swelling
    
  • Rash
    

• Interpretation of leukocytosis:
  
  • Elevated WBC counts are highly nonspecific and rarely change management. They have equal chances of appropriately and inappropriately influencing care
    
  • Duration of leukocytosis:
    
    • Hours to days: More likely to be acute event (infection, acute leukemia)
      
    • Months to years: Chronic inflammatory states or hematologic malignancies (rheumatoid arthritis, solid organ tumors, chromic leukemias, lymphomas)
      
• Cell count and differential:
  
  • If obtained be sure to evaluate absolute cell counts, percentile counts will be spuriously elevated if other cell lines are low
    
  • Look for the presence of a “left shift” (immature cells in circulation). Normal ratio is 1 band cell for every 10 neutrophils in circulation. This may indicate acute infection, or malignancy. Demargination should not cause a left shift.
    
  • Differential rarely provides additional helpful information and cannot reliably distinguish between bacterial and viral infections.
    
• Manual differential or peripheral blood smear:
  
  • Can be ordered if concern for lab error. Nucleated RBCs, or clumped platelets may cause spurious results in automated tests.
    
• RBC and platelet counts:
  
  • Low counts may suggest malignancy or bone marrow infiltration
    
• Pediatrics:
  
  • Evaluation of young febrile children (<36 mo):
    
    • WBC >15,000 is associated with a high risk of serious bacterial infection and in the appropriate clinical context should prompt clinicians to consider antibiotics, blood cultures, and possible admission.
      
    • Providers should not be reassured by only moderately elevated WBC counts 15–25,000
      
    • Conversely, the presence of a significantly elevated WBC count >25,000 does not signify more significant illness
      
    • Crying shown to elevate WBC count 113%