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Hemolytic anemia arises from a shortened survival of red blood cells (RBCs) due to an inherent abnormality of the cell, environmental factors, or both. It can be characterized by varying degrees of anemia, jaundice, an enlarged spleen, or combinations of these conditions. If the hemolysis is massive, the urine may become dark due to hemoglobinuria. Findings on examination of the peripheral blood typically include changes in the
The major categories of hemolytic anemia are: 1) immune-mediated (alloimmune or autoimmune), 2) membrane defects (spherocytosis, elliptocytosis), 3) enzyme defects (glucose-6-phosphate dehydrogenase [G6PD] deficiency, pyruvate kinase deficiency), and 4) hemoglobin defects (sickle cell disease, thalassemia).
Hemolysis and anemia may be so severe in Rh hemolytic disease that it causes intrauterine death (hydrops fetalis) or severe anemia, jaundice, and hepatosplenomegaly soon after birth. The complete blood count (CBC) shows anemia with nucleated RBCs, reticulocytosis, and an absence of spherocytes. Results of the direct
The severity of the jaundice determines the need for phototherapy (mild jaundice) or exchange transfusion (severe jaundice). Anemia may persist for up to 8 weeks. Packed RBC transfusion may be needed, depending on the degree of
AIHA is characterized by the production of antibodies against an individual's own erythrocyte membrane antigens, which leads to hemolysis. The exact incidence is not known, but it is estimated to be less than 0.2 per 100,000 children younger than 20 years of age. The peak incidence occurs in
Patients who have AIHA usually present with pallor, jaundice, lethargy, abdominal pain, or low-grade fever. If hemolysis is severe, the urine may be dark. Among the signs are those associated with hyperdynamic circulation, including an enlarged spleen and liver. Laboratory studies reveal normocytic normochromic anemia with
Most patients who have AIHA exhibit mild anemia of limited duration and, therefore, do not need therapy. Because most chronic cases are mild, minimal or no intervention is necessary. If treatment is necessary, several
Transfusion
This treatment approach is needed only in life-threatening situations or as a stopgap measure while waiting for other modalities to begin working. The "least incompatible" blood may be the best choice because of
Steroids
About 80% of patients who have IgG-induced hemolytic anemia respond to steroids (1 to 2 mg/kg per day). In
Intravenous Immune Globulin (IVIG)
IVIG is effective in doses of 1 to 2 g/kg administered over 1 to 2 days. It also may be used in combined cytopenias such as Evans syndrome. The mechanism of action of this therapy is competitive inhibition of
Splenectomy
Splenectomy is effective in cases of AIHA in which most of the hemolysis is in the spleen, such as IgG-induced AIHA. It is not as effective in IgM-induced disease because most of the hemolysis in this condition occurs in the
This hemolytic anemia is caused by a defect in the skeleton of the RBC membrane that generally affects the spectrin component. The characteristic finding is increased numbers of spherocytes in the peripheral blood.
Patients may be diagnosed as early as in the neonatal period or in adulthood with or without symptoms. The cardinal features are anemia, jaundice, and splenomegaly. Some patients may have all three, but others are
Neonatal HS
Most patients are symptomatic in the neonatal period, usually with jaundice appearing in the first 48 hours. Occasionally, the jaundice appears later. Anemia generally is not severe unless it is compounded by physiologic anemia, and splenomegaly is uncommon. Because the bone marrow response to anemia in the neonatal period is not brisk, particularly during the period of physiologic anemia, reticulocytosis is not a dependable sign. Serum
Mild HS
About 20% to 30% of patients who have HS have such mild disease that they remain asymptomatic or only very mildly or occasionally symptomatic until adulthood, when they present with complications such as gallstones.
Even though chronic hemolytic anemia is the norm in HS, other forms of anemia can complicate the picture. Viral-induced bone marrow aplasia follows infection with parvovirus B19 in any patient who has a hematologic disease that is characterized by shortened survival of RBCs. The virus infects erythroid cells in the marrow and leads to an arrest in development. The virus, which is responsible for the febrile childhood illness erythema infectiosum (fifth disease), also
B19 sometimes leads to nephropathy. Because the virus also can affect fetuses and lead to abortion, isolation precautions are required to protect pregnant women from hospitalized children. Infected children are contagious during the period of aplasia, but not when the rash appears.
For patients who have poor dietary intake of folate and are not taking supplementary folic acid or who are pregnant, the unsatisfied increased requirement for folic acid by the hyperactive erythroid precursors may lead to
Pigment gallstones may occur as early as 3 years of age, although the peak incidence is in adolescence and adulthood. The reported incidence is 5% among those younger than 10 years of age, 40% to 50% in the 10- to
During the first 6 years of life, if the patient has compensated anemia, is growing well, and can keep up with his or her peers in most activities, it is prudent to limit intervention to 1 mg/d of folic acid supplement. Subsequently, depending on the severity of the disease, splenectomy is indicated because the response rate is 100%. The
This hemolytic anemia results from oxidative damage to RBCs as a consequence of the loss of the protective effect of the enzyme G6PD. The prevalence of G6PD deficiency varies among populations and appears related to the prevalence of malaria in certain geographic areas. For example, the rate is higher in regions of Africa in which malaria is endemic. The disease also occurs at a higher frequency in
Drug-induced Hemolysis
A plethora of drugs and chemicals have been associated with either hemolysis in vitro or subclinical and clinical hemolysis in the presence of G6PD deficiency ( Table ). These substances all have the ability to stimulate the
CLINICAL ASPECTS
There are three primary clinical presentations of G6PD deficiency: neonatal jaundice, acute hemolysis beyond the neonatal period, and chronic hemolysis (congenital nonspherocytic hemolytic anemia).
Neonatal Jaundice
Acute hemolysis in the neonatal period is characterized by the onset of jaundice on the second or third day of life that is out of proportion to the degree of anemia. Because the degree of jaundice may vary from mild to severe, its management can range from simple observation to exchange transfusion. Not all infants who have G6PD deficiency develop neonatal jaundice, and in those who
Because the enormity of G6PD deficiency as a health problem varies geographically, neonatal screening should be recommended and instituted only in areas in which there is a high prevalence. Cord blood screening currently is performed in Thailand, Malaysia, and Sardinia and is recommended in several countries in western Africa, deficiencies. This author feels that in areas of the world where beans are a dietary staple, most notably in the Middle East, qualitative assays (electrophoresis) should be performed before giving advice on ingestion of