HEMATOLOGY, ONCOLOGY, ALLERGY,
AND IMMUNOLOGY
TREATMENT
■ Treat underlying cause.
■ Provide PRBC transfusion as needed. Most sources recommend maintaining
hemoglobin above 10 g/dL in patients with evidence of cardiac ischemia.
Young, healthy patients may tolerate lower hemoglobin levels.
HEMOLYTIC ANEMIA
Hemolytic anemia results from the destruction of RBCs due to an inherited
oracquireddisorder (see Table 9.2). Destruction may occur within the blood
vessels (intravascular hemolysis) or as a result of sequestration elsewhere in
the body (extravascular hemolysis).
Signs and symptoms are generally attributed to the resultant anemia and in-
clude shortness of breath, fatigue, and pale or yellow skin. The spleen may be
enlarged, indicating splenic sequestration and destruction of RBC. Patients
with hemolysis may also present with symptomatic cholelithiasis or cholecysti-
tis as a result of bilirubingallstone formation.
A variety of tests are useful in the evaluation of the patient with suspected he-
molytic anemia (see Table 9.3).
Hereditary Spherocytosis
This autosomal dominant disease with a defect in red cell membrane protein
is common among persons of Northern European descent. Severity of hemo-
lysis ranges from mild to severe.
PATHOPHYSIOLOGY
■ RBCs take on a microspherocytic shape that is unable to pass through the
spleen→RBC destruction.
SYMPTOMS/EXAM
■ Anemia, jaundice, splenomegaly
■ Symptoms/findings consistent with cholelithiasis are common.
DIAGNOSIS
■ Peripheral smear with spherocytes
■ Negative Coombs test (to rule out autoimmune hemolytic anemia)
■ MCV may be decreased, indicating chronic hemolysis.
■ Osmotic fragility test is confirmative.
TABLE 9.2. Classification of Hemolytic Anemia
HEREDITARY ACQUIRED
Hereditary spherocytosis Immune-mediated
Thalassemia Microangiopathic
G6PD deficiency Infection (eg, malaria, babesiosis)
Sickle cell disease
Red cell production, measured
by a reticulocyte count, should
be increased in patients with
hemolytic anemia.