Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 1)

HarrisonsInternalMedicine Chapter102.AplasticAnemia,Myelodysplasia, and Related Bone Marrow Failure SyndromesAplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes: IntroductionThehypoproliferativeanemias arenormochromic,normocyticormacrocytic and are characterized by a low reticulocyte count. Deficient production of RBCs occurs with marrow damage and dysfunction, which may be secondary to infection, inflammation, and cancer. Hypoproliferative anemia is also a prominent feature of hematologic diseases that are described as bone marrow failure states; these include aplastic anemia, myelodysplasia (MDS), pure red cell aplasia (PRCA), and myelophthisis. Anemia in these disorders is often not a solitary or even the major hematologic finding. More frequent in bone marrow failure is...
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Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 1) Chapter 102. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes (Part 1) Harrisons Internal Medicine > Chapter 102. Aplastic Anemia,Myelodysplasia, and Related Bone Marrow Failure Syndromes Aplastic Anemia, Myelodysplasia, and Related Bone Marrow FailureSyndromes: Introduction The hypoproliferative anemias are normochromic, normocytic ormacrocytic and are characterized by a low reticulocyte count. Deficient productionof RBCs occurs with marrow damage and dysfunction, which may be secondary toinfection, inflammation, and cancer. Hypoproliferative anemia is also a prominentfeature of hematologic diseases that are described as bone marrow failure states;these include aplastic anemia, myelodysplasia (MDS), pure red cell aplasia(PRCA), and myelophthisis. Anemia in these disorders is often not a solitary oreven the major hematologic finding. More frequent in bone marrow failure ispancytopenia: anemia, leukopenia, and thrombocytopenia. Low blood counts in the marrow failure diseases result from deficienthematopoiesis, as distinguished from blood count depression due to peripheraldestruction of red cells (hemolytic anemias), platelets (idiopathicthrombocytopenic purpura or due to splenomegaly), and granulocytes (as in theimmune leukopenias). Hematopoietic failure syndromes are classified by dominant morphologicfeatures of the bone marrow (Table 102-1). While practical distinction amongthese syndromes usually is clear, they can occur secondary to other diseases, andsome processes are so closely related that the diagnosis may be complex. Patients may seem to suffer from two or three related diseasessimultaneously, or one diagnosis may appear to evolve into another. Many of thesesyndromes share an immune-mediated mechanism of marrow destruction andsome element of genomic instability resulting in a higher rate of malignanttransformation. Table 102-1 Differential Diagnosis of PancytopeniaPancytopenia with Hypocellular Bone MarrowAcquired aplastic anemiaConstitutional aplastic anemia (Fanconis anemia, dyskeratosis congenita)Some myelodysplasiaRare aleukemic leukemia (AML)Some acute lymphoid leukemiaSome lymphomas of bone marrowPancytopenia with Cellular Bone MarrowPrimary bone marrow diseases Secondary to systemic diseases Myelodysplasia Systemic lupus Paroxysmal nocturnalhemoglobinuria erythematosus Myelofibrosis Hypersplenism Some aleukemic leukemia B12, folate deficiency Myelophthisis Overwhelming infection Bone marrow lymphoma Alcohol Hairy cell leukemia Brucellosis Sarcoidosis Tuberculosis Leishmaniasis Hypocellular Bone Marrow ± Cytopenia Q fever Legionnaires diseaseAnorexia nervosa, starvationMycobacteria