Complications
Transient aplastic crises are most commonly due to infection with parvovirus B19 infection, and may necessitate short-term red blood cell transfusions.
Pregnant patients with Hb H disease may require transfusion.
Complications related to carrying a fetus with hydrops fetalis include placentomegaly, severe pre-eclampsia, hypertension, and haemorrhage. Therefore, genetic counselling is essential in patients at risk for carrying such a fetus.
Acute haemolytic 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.[110]
Patients with haemoglobin H (Hb H) disease have a high likelihood of developing iron overload over time and should be carefully monitored.[5][71][72]
Monitor chelation therapy with the aim of reducing iron toxicity and maintaining near normal iron levels.[16]
Transfusion-dependent patients begin chelation therapy if serum ferritin level is >1797.6 picomol/L (>800 nanograms/mL).[16]
Patients with thalassaemia are at risk for cholelithiasis due to chronic haemolysis.[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-thalassaemia major in North America, there was evidence of HCV exposure in 70% of those aged ≥25 years and 5% of those aged 0 to 15 years.[111] 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 patients with transfusion-dependent thalassaemia may increase transfusion needs.[112]
The rate of alloimmunisation in a predominantly Asian patient population in North America receiving transfusion therapy for either beta- or alpha-thalassaemia was 22%.[93] Patients who received transfused blood that was phenotypically matched for the Rh and Kell systems had a much lower rate of alloimmunisation of 2.8%. To minimise the risk of alloimmunisation, thalassaemia 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 haematopoiesis.[21]
Splenomegaly is common in patients with Hb H disease; more often in non-deletional than deletional Hb H disease.
In select patients, splenectomy may increase haemoglobin levels and/or relieve symptoms.
Guidelines suggest considering splenectomy for patients with the following features: moderately severe anaemia; episodes of acute haemolysis requiring frequent transfusions; long-term complications of chronic haemolytic anaemia; symptomatic splenomegaly.[16]
Splenectomy is not recommended for patients with Hb H disease with severe anaemia, who may be at higher risk of complications and still require transfusions postsplenectomy.[16]
Splenectomy is not recommended in young children because of the risk of sepsis.[16]
The potential for serious complications, including infection, thrombosis, and pulmonary hypertension, requires careful consideration before proceeding.[87][88] Discuss the risks and benefits of splenectomy, and alternative treatment options, with the patient.
Patients with alpha-thalassaemia major are not likely to benefit from splenectomy, and it is not recommended in these patients.[16]
Osteopenia may develop in patients with Hb H disease.[69]
Children with thalassaemia 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 thalassaemia.[113][114]
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