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

Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes Part 1 Harrison's Internal Medicine > Chapter 102.. Aplastic Anemia, Myelodysplasia, and Related Bone Marrow

Chapter 102 Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes

(Part 1)

Harrison's Internal Medicine > Chapter 102 Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes

Aplastic Anemia, Myelodysplasia, and Related Bone Marrow Failure Syndromes: Introduction

The hypoproliferative anemias are normochromic, normocytic or macrocytic 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 pancytopenia: anemia, leukopenia, and thrombocytopenia

Low blood counts in the marrow failure diseases result from deficient hematopoiesis, as distinguished from blood count depression due to peripheral destruction of red cells (hemolytic anemias), platelets (idiopathic thrombocytopenic purpura or due to splenomegaly), and granulocytes (as in the immune leukopenias)

Hematopoietic failure syndromes are classified by dominant morphologic features of the bone marrow (Table 102-1) While practical distinction among these syndromes usually is clear, they can occur secondary to other diseases, and some processes are so closely related that the diagnosis may be complex

Patients may seem to suffer from two or three related diseases simultaneously, or one diagnosis may appear to evolve into another Many of these syndromes share an immune-mediated mechanism of marrow destruction and some element of genomic instability resulting in a higher rate of malignant transformation

Table 102-1 Differential Diagnosis of Pancytopenia

Pancytopenia with Hypocellular Bone Marrow

Acquired aplastic anemia

Constitutional aplastic anemia (Fanconi's anemia, dyskeratosis congenita) Some myelodysplasia

Rare aleukemic leukemia (AML)

Some acute lymphoid leukemia

Some lymphomas of bone marrow

Pancytopenia with Cellular Bone Marrow

Primary bone marrow diseases

Myelodysplasia

Paroxysmal nocturnal

Secondary to systemic diseases

Systemic lupus

hemoglobinuria

Myelofibrosis

Some aleukemic leukemia

Myelophthisis

Bone marrow lymphoma

Hairy cell leukemia

erythematosus

Hypersplenism

B12, folate deficiency Overwhelming infection Alcohol

Brucellosis Sarcoidosis Tuberculosis Leishmaniasis

Hypocellular Bone Marrow ± Cytopenia

Q fever

Legionnaires' disease

Anorexia nervosa, starvation

Mycobacteria