Microcytic Anemias Quiz

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Questions and Answers

What is the hallmark of all microcytic anemias?

Decrease in hemoglobin synthesis (correct)

Increase in red blood cell production

Normal iron levels in the blood

Increase in globin synthesis

Which of the following conditions is most commonly associated with sideroblastic anemia?

Hemolytic anemia

Chronic alcoholism (correct)

Sickle cell anemia

Iron deficiency anemia

Which of the following conditions is associated with intestinal malabsorption syndromes?

Irritable bowel syndrome

Chron's disease

Sprue (correct)

Celiac disease

Which substance negatively regulates the synthesis of heme?

Iron Signup and view all the answers

What is characteristic of total iron binding capacity (TIBC) in anemia of chronic disease (ACD)?

Low TIBC Signup and view all the answers

What symptom is typically observed in patients with vitamin B12 deficiency?

Glossitis with a smooth, sore tongue Signup and view all the answers

Which of the following laboratory findings is commonly seen in vitamin B12 deficiency?

Oval macrocytes in peripheral blood smear Signup and view all the answers

Which vitamin deficiency is commonly associated with sideroblastic anemia?

Pyridoxine (Vitamin B6) Signup and view all the answers

In the context of microcytic anemias, what are ringed sideroblasts indicative of?

Ineffective erythropoiesis Signup and view all the answers

What percentage of patients with vitamin B12 deficiency experience neurological disease without anemia?

20% Signup and view all the answers

In patients suffering from pernicious anemia, what characteristic skin change is often observed?

Lemon-yellow skin color Signup and view all the answers

What is the primary consequence of iron accumulation in the mitochondria in sideroblastic anemia?

Formation of ringed sideroblasts Signup and view all the answers

Which therapy is most commonly associated with vitamin B6 deficiency contributing to sideroblastic anemia?

Isoniazid therapy for TB Signup and view all the answers

What type of anemia is typically associated with pernicious anemia?

Megaloblastic anemia Signup and view all the answers

Which neurologic condition is associated with vitamin B12 deficiency?

Subacute combined degeneration Signup and view all the answers

What is a common finding regarding neutrophils in vitamin B12 deficiency?

Neutrophils are hypersegmented Signup and view all the answers

What is a common peripheral blood finding in megaloblastic anemia?

Pancytopenia Signup and view all the answers

What clinical feature is specific to vitamin B12 deficiency but not to folate deficiency?

Neurologic abnormalities Signup and view all the answers

What test result would be expected in pernicious anemia related to intrinsic factor?

Impaired absorption corrected by intrinsic factor Signup and view all the answers

What type of anemia is associated with severe dietary deprivation and increased fetal demands?

Folate deficiency anemia Signup and view all the answers

Which of the following is a hallmark laboratory finding in peripheral blood for patients with megaloblastic anemia?

Hypersegmented neutrophils Signup and view all the answers

What is the underlying cause of pernicious anemia?

Lack of gastric intrinsic factor Signup and view all the answers

Which condition can lead to folate deficiency via interference with absorption?

Use of phenytoin Signup and view all the answers

Which symptoms are characteristic of subacute combined degeneration in vitamin B12 deficiency?

Absent position and vibration sensations Signup and view all the answers

What is the primary purpose of the Schilling test?

To localize the reason for B12 deficiency due to intrinsic factor deficiency Signup and view all the answers

What characteristic finding is noted in the bone marrow of a patient with aplastic anemia?

Markedly hypocellular bone marrow with almost total loss of hematopoietic cells Signup and view all the answers

Which type of cells shows an increase in number in megaloblastic anemia?

Hypersegmented polymorphonuclear leukocytes Signup and view all the answers

What type of anemia is specifically indicated by pancytopenia?

Aplastic anemia Signup and view all the answers

In which location are hematopoietic cells primarily found in adults?

Axial skeleton red marrow Signup and view all the answers

What would be an expected peripheral blood finding in a patient with aplastic anemia?

Reticulocytopenia Signup and view all the answers

What alteration is most commonly involved in the etiology of aplastic anemia?

Immunologic alterations in myeloid stem cells Signup and view all the answers

What indicates megaloblastic anemia in blood smears?

Presence of megaloblasts and enlarged red blood cell precursors Signup and view all the answers

What is the normal serum iron level?

100 µg/dL Signup and view all the answers

Which condition is associated with increased serum iron levels?

Sideroblastic anemia Signup and view all the answers

What is the typical value for Total Iron-Binding Capacity (TIBC)?

300 µg/dL Signup and view all the answers

What triggers the increase in transferrin synthesis in the liver?

Decreased ferritin stores Signup and view all the answers

Which protein is responsible for storing iron in a non-toxic form?

Ferritin Signup and view all the answers

Which of the following statements about hemosiderin is true?

It correlates with changes in ferritin stores. Signup and view all the answers

What is a common use of Prussian blue stain?

To stain hemosiderin Signup and view all the answers

What change occurs in serum ferritin levels during anemia of chronic disease?

Increased ferritin levels Signup and view all the answers

What feature is characteristic of sideroblastic anemia in bone marrow aspirate?

Ringed sideroblasts with iron granules Signup and view all the answers

What is the primary cause of sideroblastic anemia?

Defect in mitochondrial heme synthesis Signup and view all the answers

Which of the following best describes the morphology of megaloblastic anemia?

Large, abnormal-appearing erythroid precursor cells Signup and view all the answers

What laboratory finding is most associated with lead poisoning?

Coarse basophilic stippling of red blood cells Signup and view all the answers

What is a common consequence of lead poisoning in children?

Psychomotor developmental delays Signup and view all the answers

Which vitamin deficiencies are typically implicated in megaloblastic anemia?

Vitamin B12 and folate Signup and view all the answers

What is the most common blood finding in both forms of megaloblastic anemia?

Abnormalities in peripheral blood findings Signup and view all the answers

What is the mechanism of ineffective erythropoiesis in megaloblastic anemia?

Delayed DNA replication and division Signup and view all the answers

Study Notes

Anemia of Chronic Disease & Sideroblastic Anemia

Anemia of Chronic Disease (ACD) is the second most common type of anemia after iron deficiency anemia.
It's a common finding in hospitalized patients.
Etiology includes chronic inflammation/infections (e.g., rheumatoid arthritis, tuberculosis), alcoholism, and malignancy.

Serum Iron: Bound to transferrin; normal level ~100 µg/dL. Transferrin, a liver-synthesized protein, binds iron. The amount of iron entering macrophages equals the amount leaving to bind with transferrin. Decreased serum iron occurs in iron deficiency (IDA). Increased serum iron occurs in iron overload diseases (sideroblastic anemia and hemochromatosis).
Total Iron-Binding Capacity (TIBC): Correlates with transferrin; normal ~300 µg/dL. Decreased ferritin stores lead to increased liver transferrin synthesis. Iron deficiency increases transferrin and TIBC.

Ferritin is a soluble iron-binding storage protein synthesized by bone marrow macrophages and hepatocytes. Iron is stored in a non-toxic form.
Macrophages are the primary storage site for ferritin from senescent red blood cells in the bone marrow.
1 μg/L serum ferritin correlates with 8 mg of storage iron.
Inflammation increases ferritin production.
Decreased serum ferritin is a sign of iron deficiency.
Increased serum ferritin occurs in ACD and iron overload diseases (e.g., hemosiderosis, hemochromatosis).

Hemosiderin is an insoluble product of ferritin degradation in lysosomes.
Decreased and increased hemosiderin levels correlate with ferritin changes.
Stains blue with Prussian blue stain.

Red Blood Cell Distribution Width (RDW)

RDW reflects variations in red blood cell size (anisocytosis).
Increased RDW is significant.
Increased RDW signifies an irregular mixture of microcytic and normocytic cells as seen in iron deficiency anemia.

Mean Corpuscular Hemoglobin Concentration (MCHC)

MCHC is the average hemoglobin concentration in red blood cells.
Decreased MCHC correlates with decreased hemoglobin synthesis, which can signify microcytic anemia (e.g., iron deficiency). Red cells have less hemoglobin (hypochromasia).
Increased MCHC reflects hereditary spherocytosis. Spherocytes lack a central pallor (hyperchromasia / hyperchromia).

Hematologic Cluster of Differentiation Markers ("CDs")

CDs are differentiation markers of blood cells.
Different CDs identify different cell types (e.g., T lymphocytes, monocytes, granulocytes).

Example: PBS in Microcytic Hypochromic in Iron Deficiency

Image of a peripheral blood smear showing microcytic hypochromic red blood cells indicative of iron deficiency.

Pathophysiology of Microcytic Anemias (Including Sideroblastic Anemia)

Decreased hemoglobin synthesis is a hallmark of all microcytic anemias.
Microcytic anemia is from decreased production of heme and/or globin chains.

Anemia of Chronic Disease (ACD)

ACD is the second most common anemia after iron-deficiency anemia.
Common in hospitalized patients.
Causes include chronic inflammation (e.g., rheumatoid arthritis), infections (e.g., tuberculosis), and chronic renal disease.
It also occurs in alcoholism and malignancy.

Regulation of Iron Absorption

Diagram illustrating iron absorption regulation. Key elements, such as heme carrier protein 1, ferroportin 1, hepcidin, liver, mucosa ferritin, DMT1, plasma transferrin, erythroid marrow, are vital in the process.

Pathogenesis of Anemia of Chronic Disease (ACD)

Decreased heme synthesis
Decreased erythropoietin (EPO) production
Hepcidin increased production by the liver.

Comparison Between IDA and ACD

Comparison table showing differences in serum iron, TIBC, transferrin saturation, and serum ferritin levels between iron deficiency anemia (IDA) and ACD.

Treatment of ACD

Treating the underlying disease is crucial.
Erythropoietin (EPO) injections can improve red blood cell production, particularly in chronic kidney disease.
Hepcidin antagonists are a relatively new treatment option.

Laboratory Studies to Differentiate Microcytic Anemias

Table showing laboratory differences in ferritin, serum iron, TIBC, and transferrin saturation levels between different microcytic anemias (iron deficiency, thalassemia, and ACD).

Sideroblastic Anemia

Sideroblastic anemia is an iron overload type of anemia.
Due to a defect in heme synthesis within red blood cell precursors' mitochondria.
Causes: chronic alcoholism, pyridoxine deficiency, lead poisoning, and hereditary types.
Pathogenesis: heme's negative feedback on 6-aminolevulinic acid synthase (ALA); iron accumulation.

Sideroblastic Anemia: Morphology

Ringed sideroblasts are a defining characteristic.
Dark blue iron granules surround the nucleus.

Lead Poisoning and Sideroblastic Anemia

Lead poisoning affects children mainly and can cause sideroblastic anemia.
Lead-based paint, old homes, homemade pottery glazes can be sources.
Causes pica (abnormal cravings).
Peripheral blood smear reveals coarse basophilic stippling.
Lead denatures ribonuclease, which causes ribosomes to persist in the cytoplasm.

Laboratory Findings in Common Types of Microcytic Anemias

Table comparing different tests, like MCV, serum iron, TIBC, ferritin, RDW, Hb electrophoresis, etc., in various microcytic anemias.

Megaloblastic and Aplastic Anemias

Megaloblastic and aplastic anemias are distinct. Megaloblastic anemias are due to impaired DNA synthesis (vitamin B12 or folate deficiency). Aplastic anemia reflects bone marrow failure.

Megaloblastic Anemia

Defined by large, abnormal-appearing erythroid precursors (megaloblasts) in the bone marrow.
Results from vitamin B12 or folate deficiency affecting DNA synthesis, causing replication delay but normal cytoplasmic maturation.

Roles of Vitamin B12 and Folate in DNA Synthesis

Diagram outlining the roles of Vitamin B12 and folate in DNA synthesis pathways.

Megaloblastic Anemia: Laboratory Abnormalities

Pancytopenia: decreased red, white, and platelets.
Oval macrocytosis: enlarged red blood cells (MCV >110).
Hypersegmented neutrophils: increased number of lobes .
Megaloblastic hyperplasia: significant red cell precursor changes in bone marrow.

Pernicious Anemia

Autoimmune gastritis is the most common cause.
Leads to lack of intrinsic factor, hindering Vitamin B12 absorption.
Often affects older individuals.
Symptoms include subacute combined degeneration of the spinal cord, peripheral neuropathy, and macrocytic anemia.

Vitamin B12 Deficiency

Subacute combined degeneration (SACD) of the spinal cord is a severe complication of B12 deficiency.
Posterior column dysfunction diminishes vibratory sensation and proprioception (joint sense).
Lateral corticospinal tract dysfunction causes spasticity.
Dorsal spinocerebellar tract dysfunction results in ataxia.

Folic Acid (Folate Deficiency) Anemia

Similar to B12 deficiency; predisposes to megaloblastic anemia.
Mechanisms causing folate deficiency include dietary deprivation, pregnancy, phenytoin use, oral contraceptives, chemotherapy, increased demand, and intestinal malabsorption.

Clinical Features of B12 Deficiency

Anemia symptoms
Glossitis (smooth, sore, inflamed tongue).
Neurologic disease: peripheral neuropathy, subacute combined degeneration (SACD), dementia, and in some cases, even neurological symptoms without accompanying anemia (20%).

Pernicious Anemia and Lab Findings

Yellowish-lemon skin with significant pallor is a common sign of pernicious anemia.
Laboratory findings include decreased serum vitamin B12, increased serum homocysteine and methylmalonic acid, peripheral blood smear showing pancytopenia, oval macrocytes, and hypersegmented neutrophils, bone marrow showing megaloblastic cells, and a Schilling test to determine the cause of B12 deficiency.

Megaloblasts and Bone Marrow Aspirate

Image of a bone marrow aspirate showing megaloblasts, indicating a lack of nuclear maturation associated with megaloblastic anemia.

Clinical and Laboratory Findings in Vitamin B12 and Folic Acid Deficiencies

Table comparing the presence/absence of laboratory and clinical findings in pernicious anemia, other B12 deficiencies, and folic acid deficiency.

Peripheral Blood Smear in Different Subtypes of Anemia

Examples of peripheral blood smears representing different anemias: iron deficiency, thalassemia, megaloblastic anemia, and others.

Where is the Marrow?

Overview of hematopoietic marrow location according to developmental stage (embryonic, newborn, childhood, adult).

Aplastic Anemia

Characterized by bone marrow hypocellularity (empty marrow) with a significant decrease in all hematopoietic cells.
Causes include immunologic alterations in myeloid stem cells leading to cytokine-mediated destruction, mutations in TERT gene, and certain environmental factors.

Aplastic Anemia: Etiology

Idiopathic (unknown cause) is common.
Drugs (e.g., alkylating agents, antimetabolites) can be a factor, as are certain toxic chemicals, infections (EBV, CMV), physical agents (radiation), and some other causes.

Aplastic Anemia: Clinical Features

Fatigue, breathlessness due to anemia.
Fever due to infection (neutropenia).
Bleeding due to thrombocytopenia.
Pancytopenia, and reticulocytopenia in peripheral blood smear.

Aplastic Anemia: Management

Discontinuation of the offending drug (if drug-related).
Transfusions (if needed), and blood should be irradiated.
Immuno-suppressive therapies.
Bone marrow transplantation (good prognosis for young patients if a matched donor is available).

Fanconi Anemia

Fanconi anemia (FA) is a hereditary bone marrow failure syndrome with significant DNA damage sensitivity.
15 genes are implicated (FANC genes, such as FANCD1/BRCA2)
Can lead to myelodysplastic syndromes, acute myeloid leukemia (AML), and epithelial tumors.
Immunosuppressive treatments are not effective.

Pure Red Cell Aplasia "PRCA"

A rare type of aplasia affecting only red blood cell precursors.
Acute, self-limited cases occur in association with viral infections (e.g., parvovirus B19), while others are chronic and congenital.
Drug-induced (e.g., phenytoin).
Other causes include thymomas and certain leukemias.

Reprogramming of Mature Cells to Induced Pluripotent Stem Cells

Technique of generating induced pluripotent stem cells (iPS cells) from mature cells using stem cell genes (SOX2, c-Myc, KLF4, and Nanog).

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Description

Test your knowledge on microcytic anemias and their characteristics. This quiz covers various aspects including conditions associated with anemia, laboratory findings, and the effects of vitamin deficiencies. Perfect for students or healthcare professionals studying hematology.