![]() 22 The red cell distribution width (RDW) is increased (>14) in most patients. 21 The mean corpuscular hemoglobin concentration (MCHC) is increased (≥34.5g/dL) due to relative cellular dehydration in >50% of patients. 11, 20 The mean corpuscular volume (MCV) is normal or slightly decreased in most patients except in severe cases, when it is decreased despite reticulocytosis, reflecting membrane loss and cellular dehydration. The majority of HS patients have some degree of anemia with reticulocytosis. 17- 19 These patients frequently remain transfusion dependent and suffer from severe HS.įlow cytometric analysis of eosin-5-maleimide-labeled erythrocytes (EMA binding) or incubated osmotic fragilityĮrythrocyte indices. A subset of patients presents with severe anemia in utero or immediately after birth and require red blood cell transfusion. Most of these patients become transfusion-independent during the first year of life. 15, 16 Others present with significant anemia presenting in the first few weeks of life and may require several transfusions in infancy. Some patients present with significant neonatal jaundice requiring phototherapy or even exchange transfusion. 12- 14 Chronically transfused patients are at risk for developing complications of recurrent transfusion and iron overload. The most severely affected patients are transfusion-dependent and almost always have recessive HS. ![]() This category includes patients with both dominant and recessive HS. The remaining 5-10% of HS patients experience moderate to severe anemia. 11 These patients are not anemic and are usually asymptomatic. erythrocyte production and destruction are balanced. Approximately a quarter of HS patients have compensated hemolysis, i.e. By late childhood, palpable splenomegaly is found in most HS patients. unconjugated hyperbilirubinemia without detectable bilirubinuria. ![]() The jaundice is typically acholuric, i.e. Jaundice is visible at some time in over half of HS patients, usually in association with viral infection or other stress. 3 The majority of HS patients have incompletely compensated hemolysis with mild to moderate anemia that is asymptomatic except for fatigue and pallor. Anemia is the most frequent finding at presentation (50%), followed by splenomegaly, jaundice, or a positive family history. HS may present at any age, but typically it presents in childhood. Splenic destruction of poorly deformable HS erythrocytes is the primary cause of hemolysis experienced by HS patients. 2 Increased erythrocyte fragility leads to vesiculation and membrane loss. 4 The loss of surface area results from increased membrane fragility due to primary and secondary abnormalities in erythrocyte membrane proteins, particularly ankyrin, α- and β-spectrin, band 3, and protein 4.2 ( Figure 1). The principal abnormality in HS erythrocytes is loss of membrane surface area relative to intracellular volume, which leads to spherically shaped erythrocytes with decreased deformability. Clinical, laboratory, and molecular heterogeneity characterize the HS syndromes. It is the most common inherited anemia in individuals of northern European ancestry, affecting ∼ 1:2500 individuals in the United States. ![]() HS occurs worldwide in all racial and ethnic groups. 2 HS was first described based on the finding of spherocytes, characteristic erythrocytes lacking central pallor, on peripheral blood smear. The hereditary spherocytosis (HS) syndromes are a group of disorders associated with a primary defect in erythrocyte membrane proteins. ![]() However, most elliptocytosis patients are asymptomatic and do not require therapy. The hereditary elliptocytosis syndromes are the most common primary disorders of erythrocyte membrane proteins. Current management guidelines acknowledge these important considerations when entertaining splenectomy and recommend detailed discussion between health care providers, patient, and family. Once considered routine, growing recognition of the longterm risks of splenectomy, including cardiovascular disease, thrombotic disorders, and pulmonary hypertension, as well as the emergence of penicillin-resistant pneumococci, a concern for infection in overwhelming postsplenectomy infection, have led to re-evaluation of the role of splenectomy. Treatment of hereditary spherocytosis with splenectomy is curative in most patients. Among this group, hereditary spherocytosis patients are more likely to experience symptomatic anemia. Classified by distinctive morphology on peripheral blood smear, these disorders are characterized by clinical, laboratory, and genetic heterogeneity. Primary abnormalities of the erythrocyte membrane, including the hereditary spherocytosis and hereditary elliptocytosis syndromes, are an important group of inherited hemolytic anemias. ![]()
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