Complications
Transient aplastic crisis due to parvovirus B19 infection may necessitate short-term red cell transfusions.
Pregnant patients with Hb H disease may require transfusion.
Complications related to carrying a fetus with hydrops fetalis include placentomegaly, severe preeclampsia, hypertension, and hemorrhage. Therefore, genetic counseling is essential in patients at risk for carrying such a fetus.
Acute hemolytic reactions (with rare mortality), transfusion-related acute lung injury (approximately 1 in 5000 transfusions), and less severe reactions such as mild anaphylactoid allergic reactions (3% of transfusions) may occur.[117]
Patients with hemoglobin H (Hb H) disease have a high likelihood of developing iron overload over time and should be carefully monitored.[5] If the serum ferritin rises above 800 nanograms/mL, patients should undergo evaluation for iron overload in the liver and the heart.
Monitor chelation therapy with the aim of reducing iron toxicity and maintaining near normal iron levels.[16]
Patients with thalassemia are at risk for cholelithiasis due to chronic hemolysis.[21]
Symptomatic cholelithiasis may warrant cholecystectomy.
The risk for transmission of hepatitis C virus (HCV) infection has dropped dramatically in North America following improved screening of the blood supply. In a study of transfusion-dependent patients with beta-thalassemia major in North America, there was evidence of HCV exposure in 70% of those ages ≥25 years and 5% of those ages 0 to 15 years.[118] In the same study, 2.5% of those tested for hepatitis B virus (HBV) surface antigen were positive, and 2% were positive for human immunodeficiency virus (HIV). Hepatitis C virus and iron overload are risk factors for cirrhosis and hepatocellular carcinoma. Treatment of chronic hepatitis C in transfusion-dependent patients with thalassemia may increase transfusion needs.[119]
The rate of alloimmunization in a predominantly Asian patient population in North America receiving transfusion therapy for either beta- or alpha-thalassemia was 22%.[92] Patients who received transfused blood that was phenotypically matched for the Rh and Kell systems had a much lower rate of alloimmunization of 2.8%. To minimize the risk of alloimmunization, thalassemia patients should have red blood cell antigen phenotyping performed and should be transfused with leukodepleted blood matched for ABO-D and Kell antigens.
Spleen-related complications may arise as the result of ineffective erythropoiesis or extramedullary hematopoiesis.[21]
Splenomegaly is more common in nondeletional than deletional Hb H disease.
Splenectomy may be considered for painful splenomegaly or hypersplenism with associated pancytopenia.[75] The potential for serious complications, including infection, thrombosis, and pulmonary hypertension, requires careful consideration before proceeding.[88][89]
Osteopenia may develop in patients with Hb H disease.[69]
Children with thalassemia are at risk for growth retardation due to growth hormone deficiency.[21]
Growth should be monitored on age- and sex-appropriate growth charts.
The decision to administer hormone replacement therapy should be made on a case-by-case basis. Based on the results of a single clinical trial, one Cochrane review concluded with moderate certainty that use of growth hormone for 1 year may improve height velocity of children with thalassemia.[120][121]
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