The erythrocyte membrane is the most thoroughly studied biologic membrane. It is a small structure, less than 0.1% of the cell's thickness and only about 1% of its weight, but its easy accessibility has enabled researchers to characterize both its…
Medical textbooks usually include paroxysmal nocturnal hemoglobinuria (PNH) among the hemolytic anemias (as is the case herein). Doing so is not wrong because hemolysis is a defining feature of the disease. However, placing too much emphasis on the hemolytic component…
Autoimmune hemolytic anemia (AIHA) is an immunologic disorder in which antibodies are produced that target red blood cells (RBCs). AIHAs can be classified into four major types of disease: warm-reacting AIHA, cold agglutinin disease (CAD), paroxysmal cold hemoglobinuria (PCH), and…
The porphyrias are caused by reduced activity of enzymes that constitute the heme biosynthetic pathway. With the exception of porphyria cutanea tarda (PCT), all are. Porphyrins are planar molecules comprised of four pyrrole rings connected by four methene groups. Porphyrins…
Iron lacks the glitter of gold and the sparkle of silver but outshines both in biologic importance. This plebeian metal is vital to the function of a wide variety of critical enzymes, including catalases, aconitases, ribonucleotide reductase, peroxidases, and cytochromes,…
The metabolism of folate and that of cobalamin are intimately intertwined, and deficiency of either vitamin can manifest as megaloblastic anemia. The two deficiencies must be rigorously differentiated and treated specifically because their causes, mechanisms, nonhematologic expressions, courses, and prognoses…
Introduction In this chapter we attempt to provide a useful guide to the rapid and accurate diagnosis of anemia in children and young adults. We do not dwell on each diagnosis because they are described in detail throughout the book.…
Hematopoietic stem cell transplantation (HSCT) is an accepted treatment for a wide variety of diseases afflicting children, including hematologic malignancies, bone marrow failure syndromes, immunodeficiency disorders, congenital hematologic defects, and select solid tumors. HSCT generally involves a conditioning phase with…
Inherited bone marrow failure syndromes (IBMFSs) are a diverse collection of genetic disorders associated with inadequate blood cell production. Bone marrow failure (BMF) may manifest as an isolated cytopenia (pure red cell aplasia, neutropenia, or thrombocytopenia) or as pancytopenia with…
Acquired and congenital bone marrow failure syndromes are characterized by a reduction in the effective production of mature erythrocytes, granulocytes, and platelets by the bone marrow. Bone marrow failure leads to various peripheral blood cytopenias. In some conditions, only one…