Hematology Ch 19 - Bone Marrow Failure Study Resource

What is aplastic anemia

Bone marrow failure syndrome characterized by hypocellular fatty marrow, pancytopenia, and decreased hematopoietic stem cells.

What are the classic laboratory findings in aplastic anemia?

Pancytopenia, reticulocytopenia, hypocellular fatty marrow, mild macrocytosis.

What are the three major clinical consequences of pancytopenia?

Fatigue (anemia), infections (neutropenia), bleeding/bruising (thrombocytopenia).

What is the most common mechanism of acquired aplastic anemia?

Autoimmune T-cell destruction of hematopoietic stem cells.

What are three examples of acquired aplastic anemia causes?

Drugs, benzene exposure, viral infections.

What is an example of inherited aplastic anemia? .

Fanconi anemia

What does pancytopenia mean?

Decrease in RBCs, WBCs, and platelets.

What bone marrow finding is characteristic of aplastic anemia?

Markedly hypocellular marrow replaced by fat.

What reticulocyte finding is seen in aplastic anemia?

Reticulocytopenia (low reticulocyte count).

What peripheral blood finding is commonly seen in severe aplastic anemia?

Mild macrocytosis.

What finding would suggest leukemia or MDS myelodysplastic syndrome rather than aplastic anemia?

Increased blasts in the bone marrow.

What finding would suggest myelofibrosis or marrow replacement rather than aplastic anemia?

Increased reticulin fibrosis.

What is severe aplastic anemia?

Bone marrow cellularity <25% plus severe cytopenias.

What additional finding makes aplastic anemia "very severe"?

ANC <0.2 × 10⁹/L.

A patient has marrow cellularity 10% and ANC 0.1 × 10⁹/L. What is the classification?

Very severe aplastic anemia.

What is the best treatment for a young patient with severe aplastic anemia and a matched sibling donor?

Hematopoietic stem cell transplantation.

What treatment is used if no matched sibling donor is available?

Immunosuppressive therapy (ATG + cyclosporine).

Why should transfusions be used judiciously in aplastic anemia?

o avoid alloimmunization before transplant.

What is the defect in Fanconi anemia?

DNA repair defect.

What test is diagnostic for Fanconi anemia?

Diepoxybutane (DEB) chromosome breakage test.

What blood count abnormality develops in Fanconi anemia?

Pancytopenia

What congenital abnormalities are associated with Fanconi anemia?

Short stature, abnormal thumbs, skeletal abnormalities, hyperpigmentation.

What laboratory hallmark is seen in Fanconi anemia?

Chromosome fragility

Child with pancytopenia + abnormal thumbs + skin pigmentation

Fanconi anemia.

What is the primary defect in dyskeratosis congenita?

Telomerase/telomere maintenance defect.

What causes bone marrow failure in dyskeratosis congenita?

Premature death/exhaustion of stem cells.

What is the classic triad of dyskeratosis congenita?

Nail dystrophy, abnormal skin pigmentation, oral leukoplakia.

Telomerase mutation + marrow failure

Dyskeratosis congenita.

What is the genetic defect in Shwachman-Diamond syndrome?

Ribosome dysfunction.

What is the most characteristic cytopenia in Shwachman-Diamond syndrome?

Neutropenia

What major nonhematologic feature occurs in Shwachman-Diamond syndrome?

Pancreatic insufficiency.

What skeletal finding may occur in Shwachman-Diamond syndrome?

Skeletal abnormalities.

Neutropenia + pancreatic insufficiency

Shwachman-Diamond syndrome

What is Diamond-Blackfan anemia?

Congenital pure red cell aplasia.

Which cell line is primarily affected in Diamond-Blackfan anemia?

Erythroid precursors (RBCs only).

What happens to WBC and platelet counts in Diamond-Blackfan anemia?

Usually normal

What reticulocyte finding occurs in Diamond-Blackfan anemia?

Very low reticulocyte count.

At what age does Diamond-Blackfan anemia typically present?

Infancy.

Infant with severe anemia and normal WBC/platelets

Diamond-Blackfan anemia

What is TEC (Transient Erythroblastopenia of Childhood)

Temporary suppression of erythropoiesis in children.

What commonly precedes TEC?

Viral infection

Are WBC and platelet counts normal in TEC?

yes

Is TEC permanent?

No, it is self-limited

Healthy child develops anemia after viral illness

Transient Erythroblastopenia of Childhood (TEC)

What is the primary problem in Congenital Dyserythropoietic Anemia (CDA)

Ineffective erythropoiesis.

What characteristic marrow finding occurs in Congenital Dyserythropoietic Anemia (CDA)

Binucleated or multinucleated erythroid precursors.

What iron abnormality occurs in Congenital Dyserythropoietic Anemia (CDA)

Iron overload (hemosiderosis).

What reticulocyte finding occurs in Congenital Dyserythropoietic Anemia (CDA)

Reticulocytopenia

Iron overload + binucleated erythroblasts

Congenital Dyserythropoietic Anemia (CDA)

What causes myelophthisic anemia?

Bone marrow replacement by tumor, fibrosis, or other infiltrative processes.

What RBC shape is characteristic of myelophthisic anemia?

Teardrop cells (dacrocytes).

What peripheral smear finding is characteristic of myelophthisic anemia?

Leukoerythroblastic blood picture.

What does a leukoerythroblastic blood picture mean?

Nucleated RBCs and immature granulocytes in circulation.

What condition commonly causes myelophthisic anemia?

Metastatic cancer infiltration of marrow.

Cancer + teardrop cells + nucleated RBCs

Myelophthisic anemia

What causes anemia in chronic kidney disease?

Decreased erythropoietin production

What type of anemia is usually seen in Chronic Kidney Disease Anemia

Normocytic, normochromic anemia

What organ produces erythropoietin?

Kidney

Chronic Kidney Disease Anemia + normocytic anemia

Decreased EPO production

Hypocellular marrow + pancytopenia

Aplastic anemia

Hypercellular marrow + blasts

Leukemia

Hypercellular marrow + dysplasia

Myelodysplastic syndrome (MDS)

Marrow replaced by tumor/fibrosis

Myelophthisic anemia

Positive PNH clone

Paroxysmal nocturnal hemoglobinuria (PNH)

Severe aplastic anemia marrow cellularity

<25%

Platelet count criterion for severe aplastic anemia

Reticulocyte criterion for severe aplastic anemia

<20 × 10⁹/L

ANC criterion for severe aplastic anemia

<0.5 × 10⁹/L

ANC criterion for very severe aplastic anemia

<0.2 × 10⁹/L

What disorder is frequently associated with aplastic anemia?

Paroxysmal nocturnal hemoglobinuria (PNH)

How is PNH detected?

Flow cytometry for CD55 and CD59 deficiency