4. Acute Leukemia
Definition
Leukemia is a progressive, malignant disease of the blood-forming tissues marked by a distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow.
Acute leukemia is a subtype in which the involved cell line shows little or no differentiation and usually consists of blast cells. This subtype is further differentiated into acute myelogenous leukemia (AML) and acute lymphocytic/lymphoblastic leukemia (ALL).
Incidence
The incidence of AML is approximately 4:100,000. It is the more common form of acute leukemia, accounting for about 80% of diagnosed adult cases. Acute leukemia is more common in Caucasians and in males. It accounts for about 20% of cases of childhood leukemia.
ALL, the most common form of malignancy in childhood, makes up approximately 33% of all pediatric cancers. It also occurs more frequently in Caucasians. Overall, the incidence is about 30:1,000,000. For children younger than 15 years of age, the incidence of ALL in Caucasians is about 33:1,000,000, and in African Americans it is about 15:1,000,000. The disease accounts for about 80% of cases of childhood leukemia.
Etiology
Acute leukemia is not fully understood but is believed to have multiple causes. Several factors have been identified as increasing the risk for developing acute leukemia, including bone marrow damage, retroviruses, and genetic disorders such as Klinefelter syndrome or Down syndrome.
Signs and Symptoms
• Bleeding
• Bone pain
• Cranial nerve involvement (third, fourth, sixth, and seventh cranial nerves)
• Dyspnea
• Fatigue
• Fever
• Headache
• Hepatosplenomegaly
• Irritability
• Lethargy
• Lymphadenopathy
• Nausea and vomiting
• Nuchal rigidity
• Pallor
• Papilledema
• Petechiae
• Signs of bone marrow failure (e.g., anemia, thrombocytopenia, neutropenia)
• Weight loss
Medical Management
AML
Chemotherapy is the first line of treatment for AML, although only a minority of patients are cured.
Treatment is typically with an anthracycline drug singly or with an anthracenedione drug combined with arabinosyl cytosine.
Transfusion with packed cells should be administered when the patient’s hemoglobin concentration is less than 7 to 8 g/dL, or at a higher concentration in the event of cardiovascular or pulmonary compromise.
Platelets should be transfused when the count is below 10,000 to 20,000/μL. In cases of pulmonary or gastrointestinal bleeding, transfuse platelets even if the count is more than 50,000/μL; and in cases of cerebral hemorrhage, when the count is more than 100,000/μL.
Fresh frozen plasma is administered when there is a significantly prolonged physical therapy (PT).
Cryoprecipitate is given when the patient’s fibrinogen concentration is less than 100 g/dL.
The patient who becomes febrile should receive an antibiotic, which should be a third-generation cephalosporin and may or may not be combined with vancomycin.
If the patient remains febrile despite 3 to 5 days of antibiotic therapy, antifungal agents should be administered.
ALL
ALL is treated primarily with chemotherapy. For a pediatric patient, the chemotherapy agents must be administered via a centrally located, indwelling catheter or well.
Complications
Mortality is typically the consequence of pancytopenia, infection, hemorrhage, renal dysfunction, or hepatic dysfunction. Uric acid nephropathy is common in a patient with leukemia. Uric acid is produced faster than the kidneys can clear it and, as a result, precipitates in the renal tubules, culminating in renal failure.
Anesthesia Implications
Anemia decreases the oxygenation of tissues both as a result of decreased carrying capacity and a “left shift” in the O 2 dissociation curve. The reduced oxygen delivery ability results in the need for increased heart rate and thus higher myocardial oxygen consumption and demand.
Thrombocytopenia can contribute to preoperative blood loss from gastrointestinal bleeding or from hemoptysis, resulting in decreased intravascular volume. Transfusion of packed cells, platelets, fresh frozen plasma, and/or cryoprecipitate may be necessary before surgery and anesthesia. Vasodilation from general anesthesia induction or instillation of a regional anesthetic can produce profound hypotension. The patient with leukemia should be adequately hydrated before initiation of an anesthetic plan.
