A Synopsis of AFP's "Leukemia: An Overview for Primary Care"

Leukemia: An Overview for Primary Care

AMANDA S. DAVIS, MD, AnMed Health Family Medicine Residency Program, Anderson, South Carolina

ANTHONY J. VIERA, MD, MPH, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina

MONICA D. MEAD, MD, University of California–Los Angeles, Los Angeles, California
Am Fam Physician. 2014 May 1;89(9):731-738.

     Leukemia is caused by an uncontrolled stem cell proliferation in the bone marrow. The four subtypes include acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), chronic lymphocytic leukemia (CLL), and chronic myelogenous leukemia (CML). Risk factors include radiation exposure (as little as a couple of CT's), Down syndrome, neurofibromatosis, benzene, or household pesticides exposure in utero or in the first 3 years of life. 
    ALL is most common in children and young adults. Signs and symptoms include fever, lethargy, bleeding, muscle aches, and enlargement of the spleen, liver or lymph nodes. Blast cells are seen on peripheral smear or bone marrow aspirate. AML is mostly in adults. Symptoms include fever, fatigue, weight loss, shortness of breath, chest pain, bruising, nosebleeds, and menorrhagia. Pain is not common. 
     Chronic leukemia is often discovered incidentally and is more common in adults. CLL may present with an enlarged liver, spleen or lymph nodes. CML may present solely with splenomegaly.  Bleeding and bruising are rare in chronic leukemia. 
     Leukocytosis is the first laboratory indication of possible leukemia. The type of WBC proliferation will help guide diagnosis. Monocyte predominance is seen in chronic infections, such as connective tissue disorders or TB. Basophilia is common in viral infections or inflammatory conditions. Lymphocytosis is seen in EBV, CMV, TB, pertussis, or asplenia. Eosinophilia is seen in parasitic, allergic or connective tissue disorders. Neutrophil predominance can be due to inflammation, stress, drugs, or infection. 
     The criteria to order a peripheral smear includes leukocytosis, WBC count >20,000/uL, enlarged liver, spleen or lymph nodes, constitutional symptoms (fatigue, fever, night sweats) or anemia thrombocytopenia, or thrombocytosis.  
     Acute leukemia will have an increase in hematopoietic precursor blast cells. AML will have auer rods on peripheral smear or with immunophenotyping (which is done using flow cytometry or cytogenetic testing). Chronic leukemia will present with a clonal expansion of B lymphocytes (>5000/uL). Bone marrow aspiration is not necessary. CML will have the Philadelphia chromosome on immunophenotyping. 
    Treatment of leukemia should be left up to the heme-onc specialists. Tumor lysis syndrome can occur with treatment. The destroyed cancer cells can cause electrolyte disturbances and renal injury. Patients who receive immunosuppression  therapy may present with a neutropenic fever, prompting the use of broad spectrum antibiotic therapy. Survivors of leukemia have an increase risk of other cancer subtypes, especially ALL later in life. Children also have an increased risk of joint osteonecrosis.