Clinical manifestations and diagnosis
Presenting symptoms in patients with acute leukemia are highly variable (Table 3.1) but most are caused by hematopoietic insufficiency. Typically, the onset of symptoms is acute, within weeks to a few months before diagnosis, except in those patients who develop leukemia secondary to a pre-existing hematologic disease such as myelodysplastic syndromes (MDS) or myeloproliferative neoplasms. Infiltration of extramedullary organs by leukemic blasts is found in 2.5–9% of acute myeloid leukemia (AML) patients. Lymphadenopathy and/or hepatosplenomegaly are present in up to 50% of patients with acute lymphoblastic leukemia (ALL), and patients with T-lineage ALL frequently present with a mediastinal mass. Involvement of the central nervous system (CNS), most commonly manifesting in the cerebrospinal fluid (CSF), is detectable in <5% of adults with AML and in ~5% of adults with ALL at the time of initial diagnosis . Fever is one of the most common presenting symptoms in patients with acute leukemias. Fever should always be interpreted as a sign of infection, and should prompt a careful search for infectious foci. Rapid initiation of empirical, broad-spectrum antibiotic coverage is usually indicated in febrile patients. Fever as a direct manifestation of leukemia without coexisting infection is rare.