Dlood And Hemolytic Disorder Flashcards
Front
Back
What are common disorders of the blood and lymphatic system?
Red cell disorders lead to anemia (RBC deficiency). White cell disorders lead to leukemia (WBC proliferation). Haemostatic derangements lead to hemorrhagic diathesis. Splenomegaly is a feature of several hematopoietic diseases.
What is anemia?
Anemia is a reduction in oxygen transport capacity of blood due to reduction in RBC count or hemoglobin concentration.
What are the changes in the pathology of anemia?
- Bone marrow hyperplasia in red marrow that replaces the yellow marrow. 2. Peripheral blood changes in number size shape of cells and Hb concentration. 3. Extramedullary hematopoiesis in liver spleen and lymph nodes. 4. Tissue changes include pallor and fatty changes in liver and kidney due to hypoxia.
What are the causes of anemia?
- Excessive bleeding. 2. Increased red cell destruction. 3. Decreased red cell production.
How is anemia classified?
- Blood loss: Acute trauma and chronic lesions of the gastrointestinal tract gynecologic disturbances. 2. Increased destruction: Hemolytic anemia A. Intrinsic abnormalities of RBC: hereditary disorders of RBC membrane disorders of hemoglobin synthesis enzyme deficiencies. B. Acquired abnormalities: membrane defect such as Paroxysmal Nocturnal Hemoglobinuria. 3. Impaired RBC production: A. Disturbance of proliferation and maturation of erythroblasts: iron folate vit B12 deficiency. B. Disturbance of proliferation and differentiation of stem cells: aplastic anemia.
What are the features of hemolytic anemia?
- Increased rate of RBC destruction. 2. Increased rate of erythropoiesis. 3. Increased reticulocyte count. 4. Increased retention of body iron. 5. Extramedullary hematopoiesis may develop in the spleen liver and lymph nodes.
What is the difference between intravascular and extravascular hemolysis?
Intravascular hemolysis occurs within vessels and is caused by trauma toxins or heat resulting in hemoglobinemia hemoglobinuria and hemosiderinuria. Extravascular hemolysis occurs within the cells of the reticuloendothelial (RE) system.
What are the causes of hemolytic anemia?
- Disorders of RBC membrane cytoskeleton (e.g. spherocytosis). 2. Immune hemolytic anemia. 3. Traumatic hemolytic anemia. 4. Infections (e.g. malaria).
What is hereditary spherocytosis (HS)?
HS is an inherited defect in the RBC membrane rendering the RBC spheroidal and vulnerable to splenic sequestration and destruction. It is an autosomal dominant trait.
What is the pathogenesis of hereditary spherocytosis?
The abnormality lies in the protein forming the RBC membrane particularly spectrin which links to membrane proteins like ankyrin band 3 and band 4.1.
What are the morphological features of hereditary spherocytosis?
- Smear shows RBC lacking the central zone of pallor. 2. Reticulocytosis in peripheral blood. 3. Splenomegaly is moderate.
What treatment options are available for hereditary spherocytosis?
Some patients may need blood transfusions. In HS patients benefit from splenectomy but there is an increased risk of infection especially in children.
What characterizes sickle cell anemia?
Sickle cell anemia is an autosomal recessive disorder characterized by the presence of abnormal Hb (HbS) due to a mutation in the gene encoding the globin chain.
What is the etiology of sickle cell anemia?
On deoxygenation HbS molecules undergo polymerization causing RBCs to assume an elongated crescent or sickle shape.
What are the clinical features of sickle cell anemia?
- Hemolysis causing anemia. 2. Increased breakdown of Hb with bilirubin formation. 3. Capillary stasis leading to tissue ischemia and infarction.
What is thalassemia?
Thalassemia is a genetic disease characterized by decreased synthesis of alpha or beta globin chains. It is an autosomal codominant disease.
What are the types of thalassemia?
- Alpha thalassemia: globin chain is reduced or absent. 2. Beta thalassemia: globin chain is reduced.
What laboratory findings are associated with iron deficiency anemia (IDA)?
- Microcytic hypochromic anemia. 2. Low serum iron transferrin and ferritin levels. 3. Increased erythropoietin level.
What are the causes of vitamin B12 deficiency anemia?
- Long-standing malabsorption (e.g. Crohn’s disease tropical sprue). 2. Gastrectomy. 3. Ileum resection. 4. Gastric atrophy (achlorhydria in old age). 5. Pernicious anemia.
What are the clinical features of vitamin B12 deficiency anemia?
Pallor fatigability mild jaundice dyspnea congestive heart failure and neurological symptoms such as numbness tingling and loss of position sense.
What is the diagnosis for pernicious anemia?
- Low serum vitamin B12. 2. Serum antibody to intrinsic factor. 3. Moderate to severe megaloblastic anemia.
What is glucose 6-phosphate dehydrogenase deficiency?
G6PD is an enzyme in the hexose monophosphate shunt needed to produce reduced glutathione (GSH) which protects RBC from oxidative injury.
What is Paroxysmal Nocturnal Hemoglobinuria (PNH)?
PNH is an acquired membrane defect secondary to mutation affecting myeloid stem cells resulting in hemolysis at night due to blood becoming acidic during sleep.
What are the causes of extrinsic hemolytic anemia?
- Immunohemolytic anemia. 2. Traumatic hemolytic anemia. 3. Infections like malaria.
What is the morphology of megaloblastic anemias?
Hypercellular bone marrow with increased megaloblasts giant metamyelocytes hypersegmented neutrophils in peripheral blood and large egg-shaped macroovalocytes.
What are granulocytes?
Granulocytes are a type of white blood cell characterized by the presence of granules in their cytoplasm.
What is atrophic glossitis?
Atrophic glossitis is a condition characterized by inflammation and atrophy of the tongue.
What response occurs in the body to Vitamin B12 deficiency within 2-3 days?
A dramatic reticulocytic response occurs in the body.
What is aplastic anemia?
Aplastic anemia is a condition where multipotent myeloid stem cells are suppressed resulting in marrow failure and pancytopenia.
What are the causes of aplastic anemia?
- Idiopathic causes in 12% of cases. 2. Myelotoxic agents such as antineoplastic drugs alkylating agents antimetabolites benzene and chloramphenicol. 3. Community acquired viral hepatitis. 4. Inherited defects in telomerase.
What role do auto reactive T cells play in aplastic anemia?
Vague auto reactive T cells play an important role as 80% of cases respond to immunosuppressive drugs aimed at T cells.
What are the morphological features of aplastic anemia?
Hypocellular bone marrow with 90% of intertrabecular space occupied by fat with lymphocytes and plasma cells present.
What secondary changes occur due to aplastic anemia?
- Thrombocytopenia results in hemorrhage. 2. Granulocytopenia causes bacterial infection. 3. Anemia can cause fatty liver.
What is the clinical course of aplastic anemia?
It can occur in all ages and both sexes with a gradual onset symptoms such as weakness pallor dyspnea petechiae and ecchymoses.
What type of anemia does aplastic anemia resemble?
Normal bone marrow anemia.
What is the typical reticulocyte count in aplastic anemia?
Reticulocytes are reduced.
What is the treatment for aplastic anemia?
- Withdrawal of toxic drugs can cause recovery in some cases. 2. Immunosuppressive drugs. 3. Bone marrow transplant is effective.
What is myelophthisic anemia?
Myelophthisic anemia is a type of anemia caused by the replacement of marrow by tumors or other lesions.
What are potential causes of myelophthisic anemia?
- Metastatic breast prostate or lung cancer. 2. Tuberculosis. 3. Lipid storage disease. 4. Osteosclerosis.
What is the blood film characteristic of myelophthisic anemia?
Blood film shows misshapen RBCs that resemble teardrops with immature granulocytic and erythrocytic precursors indicating leukoerythroblastosis.