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Block 8 - Autoimmunity, Neoplasia, and Hematologic Disease > ASF - Anemia (Duong) > Flashcards

ASF - Anemia (Duong) Flashcards

1
Q

Describe the shape and color of these erythrocytes. What disease could this be caused by?

A

Not normal

Microcytic - RBCs are smaller than the leukocyte

Hypochromic - central pallor takes up more than 1/3 of the RBC

Presence of ovalocytes indicates poikilocytosis (abnormal shape)

Microcytic hypochromic anemia is caused by iron deficiency anemia, anemia of chronic disease, sideroblastic anemia, and thalassemia

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2
Q

An 8-year-old boy is acutely ill with a fever and bloody diarrhea a day after attending a picnic. A CBC shows low platelets, high WBC count, and anemia. You suspect infection with E. coli O157:H7. What do you expect to see on a peripheral smear?

A. Increased platelets

B. Increased microspherocytes

C. Increased schistocytes

D. Increased Howell-Jolly bodies

E. Increased acanthocytes

A

C. Increased Schistocytes

E. coli O157:H7 toxin causes hemolytic uremic syndrome (HUS), a disease characterized by intravascular hemolysis of RBCs.

Remember that intravascular hemolysis is caused by deposition of fibrin or thrombi in small vessels, which tear up RBCs as they flow through. This produces schistocytes.

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3
Q

Howell-Jolly bodies are formed after what type of surgical procedure?

A

Splenectomy

Howell-Jolly bodies are small, basophilic fragments of DNA present in RBCs. Normally, the splenic macrophages would remove these fragments. Splenectomy prevents this from happening.

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4
Q

Which condition is associated with RBCs being more prone to oxidative injury, and which type of hemolysis is observed?

A

Glucose-6-phosphate dehydrogenase deficiency

G6PD deficiency leads intravascular hemolysis because oxidative stress causes red cell lysis in the peripheral blood.

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5
Q

What is the function of glucuronyltransferase in relation to bilirubin?

A

Glucuronyltransferase conjugates bilirubin with a glucuronic acid molecule, making it more water-soluble so that it can be excreted in the urine.

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6
Q

What blood disorder is diagnosed with an osmotic fragility test, in which the cells are more prone to rupture in hypotonic solutions?

A

Hereditary Spherocytosis

This condition is caused by defects in cytoskeletal structural proteins (ankyrin, spectrin, etc.) in RBCs, which leads to membrane blebbing. Blebs are removed by splenic macrophages, decreasing the amount of cell membrane present. Decreased cell membrane inhibits biconcave shape and produces spherocytes. Spherocytes have fragile membranes that allow swelling and bursting in hypotonic solution.

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7
Q

What specific toxin can lead to aplastic anemia?

A

Benzene

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8
Q

A 27-year-old pregnant female with two children who has had no prenatal care, including pre-natal vitamins with any pregnancy, has the following CBC (below). Which set of lab findings below would be most compatible with the correct diagnosis?

A. Decreased serum iron and ferritin, increased TIBC

B. Increased serum iron and ferritin, decreased TIBC

C. Decreased serum iron, TIBC, and ferritin

D. Increased serum iron and TIBC, decreased ferritin

E. Decreased serum iron and TIBC, decreased ferritin

A

A. Decreased serum iron and ferritin, increased TIBC

A common problem in pregnant women who don’t take pre-natal vitamins is iron deficiency.

Becuase iron makes up heme, and heme makes up hemoglobin, the patient will have a low hemoglobin level.

Low iron from diet means that the iron bound to ferritin in macrophages will be used up, so ferritin will decrease

Lack of dietary and stored iron will increase the need for iron so the marrow can produce new RBCs. The liver will increase production of transferrin, which will increase TIBC.

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9
Q

You suscpect a patient has hemolytic uremic syndrome. What type of testing should be performed?

A

Serotyping for E. coli O157:H7

Acute cases of hemolytic uremic syndrome are caused by shiga-like toxin, most commonly from E. coli.

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10
Q

What type of anemia induces vitamin B12 deficiency?

A

Pernicious anemia

Pernicious anemia is caused by decreased production of intrinsic factor by the gastric parietal cells. In order for B12 to be absorbed in the terminal ileum, it must be bound to intrinsic factor. So B12 gets eliminated in feces.

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11
Q

What is the MCV of each of these types of anemias:

  1. Microcytic
  2. Normocytic
  3. Macrocytic
A
  1. Microcytic: MCV < 80
  2. Normocytic: MCV = 80 - 100
  3. Macrocytic: MCV > 100
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12
Q

What is the name of the structure the arrow is point to and condition is associated with the blood smear below?

A

Intracellular malarial parasites

Common in malarial infection with Plasmodium falciparum, ovale, vivax

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13
Q

What protein is responsible for clearing free hemoglobin in the blood?

A

Haptoglobin

Low serum haptoglobin levels indicate intravascular hemolysis

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14
Q

A 16-year-old male has splenomegaly, jaundice, and anemia. Spherocytes are noted on his peripheral blood smear and his red cells demonstrate increased osmotic fragility. The defect causing the anemia is:

A. Abnormal hemoglobin

B. Abnormal protein in the RBC cytoskeleton

C. Antibody against RBCs

D. An enzyme defect in the hexose monophosphate shunt

A

B. Abnormal protein in the RBC cytoskeleton

This case is describing hereditary spherocytosis, a genetic disorder with defective cytoskeletal proteins (ankyrin, spectrin, etc.)

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15
Q

A deficiency of what cellular structure leads to paroxysmal nocturnal hemoglobinuria?

A

GPI-anchor (PIG-A)

Lack of PIG-A prevents anchoring of decay activating factor on the RBC membrane, which makes it vulnerable to complement. At night, respiratory acidosis activates complement, which causes intravascular hemolysis.

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16
Q

In Paroxysmal Nocturnal Hemoglobinuria, which normally occurring cell markers are absent?

A

CD59 (MAC-inhibitory protein), CD55 (decay accelerating factor, DAF), and FLAER

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17
Q

What type of anemia has a normal ADAMTS13 gene and is tested by serotyping for E. coli?

A

Hemolytic Uremic Syndrome

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18
Q

A dacrocyte is another name for an RBC that has what shape?

A

Tear-drop shaped RBC

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19
Q

What molecule binds to two beta chains to stabilize the hemoglobin when it is in its deoxygenated form?

A

2,3-bisphosphoglycerate (2,3-BPG)

AKA: 2,3-diphosphoglycerate (2,3-DPG)

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20
Q

True or False: Intrinsic factor deficiency can lead to vitamin B12 deficiency.

A

True

Remember that intrinsic factor is required to be bound to vitamin B12 so that it can be absorbed in the terminal ileum. Lack of intrinsic factor means no B12 absorption.

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21
Q

What is the anemia caused by an autosomal recessive defect in DNA repair, and has a high incidence of bone marrow aplastic anemia?

A

Fanconi Anemia

Characteristics: short stature, skeletal anomalies, increased incidence of solid tumors and leukemias, bone marrow failure (aplastic anemia)

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22
Q

A patient with a high MCV and hypersegmented neutrophil histological stain likely has what condition?

A

Megaloblastic Anemia

Remember that one of the hallmarks of megaloblastic anemia are macrocytic RBCs and hypersegmented neutrophils.

Megaloblastic changes also occur in rapidly dividing cells, leading to glossitis.

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23
Q

What structures are the arrows point to and in which type of anemia would these most likely be seen?

A

Pappenheimer Bodies

Common in sideroblastic anemia (protoporphyrin deficiency –> increased free iron and decreased heme)

Pappenheimer bodies are aggregations of iron in RBCs that do not have smooth edges and there can be more than one in an RBC. This distinguishes them from Howell-Jolly Bodies (smooth, circular edges and only one per RBC)

24
Q

Metastatic adenocarcinoma in the bone marow can lead to what type of anemia?

A

Myelophthisic Anemia

Myelophthisic anemia occurs when bone marrow cells are replaced by other non-hematopoietic elements. Metastatic adenocarcinoma in the bone marrow would push out the erythropoietic stem cells, leading to anemia.

25
Q

What is the treatment for malaria?

A

Quinine drugs

26
Q

How many oxygens can a heme group bind to and how many in total for a Hb molecule?

A

Each heme group can bind 1 oxygen molecule. Each hemoglobin has 4 heme groups, so 4 oxygen molecules can bind in total.

27
Q

What is the most common anemia in hospitalized patients?

A

Anemia of Chronic Disease

Anemia of chronic disease occurs in patients with chronic inflammation or cancer.

Chronic inflammation causes production of acute phase reactants, one of which is hepcidin.

Hepcidin binds iron and sequesters it in storage to prevent production of heme –> microcytic anemia.

Acute phase reactants also decrease production of erythropoietin –> anemia

28
Q

How are schistocytes formed and which type of hemolysis results from this?

A

Schistocytes are formed when thrombi or fibrin are deposited into endothelial cells of microvasculature, which causes RBCs to be shredded up as they pass through. Damaged RBCs are called schistocytes.

Because this has occurred in the peripheral circulation, it is considered to be intravascular hemolysis

29
Q

What are the three types of intravascular hemolysis that cause the formation of schistocytes?

A
  1. Disseminated intravascular coagulation (DIC)
  2. Thrombotic thrombocytopenic purpura (TTP)
  3. Hemolytic uremic syndrome (HUS)
30
Q

What are the 4 main causes of iron deficiency anemia?

A
  1. Low dietary intake of iron
  2. Malabsorption
  3. Increased demand - pregnancy
  4. Chronic blood loss
31
Q

In which RBC condition would you see Heinz bodies and what causes them?

A

G6PD deficiency

Oxidative stress in RBCs that do not have G6PD causes aggregation of hemoglobin, which causes it to precipitate inside of the RBC.

These cells travel to the spleen where splenic macrophages remove the Heinz bodies, forming bite cells (black arrows below).

32
Q

In a patient with anemia of chronic disease, how will TIBC be changed (increased or decreased)?

A

Decreased

Patients with anemia of chronic disease will have high serum ferritin, low TIBC, and decreased serum iron and % saturation

Hepcidin binds iron and sequesters it in macrophages. High ferritin causes TIBC to be decreased.

33
Q

When is lactate dehydrogenase (LDH) seen in the blood?

A

In the presence of damaged RBCs

34
Q

How is vitamin B12 acquired in the diet?

A

Animal products (meat)

35
Q

What causes the increased blue staining in polychromatophilic RBCs?

A

Presence of residual RNA

Common in macrocytic anemias

36
Q

What is koiloncychias and in which condition is it most often seen?

A

Spooning of the fingernails

Most commonly seen in iron deficiency anemia

37
Q

Parvovirus B19 can lead to what condition?

A

Pure Red Cell Aplasia

Parvovirus B19 temporarily halts erythropoiesis, which causes anemia in patients with pre-existing marrow stress (hereditary spherocytosis, beta-thalassemia, etc.)

38
Q

What is the condition in which bone marrow is replaced by non-hematopoietic elements?

A

Myelophthisic Anemia

Main causes: infection, cancer, fibrosis

39
Q

The arrows are pointing to an enlarged RBC precursors that are oftentimes seen in what condition?

A

Pure Red Cell Aplasia

40
Q

What is RDW and what does it indicate?

A

Red-cell distribution width

Measures the spectrum of size of RBCs

Higher the RDW, the more variation in RBC size

41
Q

What is the pattern of inheritance associated with G6PD deficiency?

A

X-linked recessive

42
Q

What is the function of transferrin?

A

Transferrin binds iron that has recently been absorbed and transfers it to the spleen for storage

43
Q

What are 2 idiopathic causes of aplastic anemia?

A

Stem cell defect and immune-mediated defect

44
Q

What condition would have a coarse basophilic stippling of RBCs, increased aminolevulinic acid, and increased protoporphyrin?

A

Lead Poisoning

Lead interferes with the enzyme aminolevulinic acid dehydrogenase (ALAD), preventing protoporphyrin from being synthesized.

Iron + protoporphyrin = heme

Lack of protoporphyrin causes a buildup of iron in RBCs that clumps together, causing stippling

45
Q

What diagnostic test would be positive for extravascular autoimmune hemolytic anemia?

A

Direct Coomb’s Test (direct antibody test, DAT)

Autoimmune-mediated antibodies bind to antigens on RBCs, which induces complement and causes phagocytosis via macrophages of the spleen, liver, and bone marrow

46
Q

What are the lab findings in iron deficiency anemia?

Hemoglobin and Hematocrit:

MCV:

MHC:

MCHC:

A
  1. Hemoglobin and hematocrit - decreased
  2. MCV - microcytosis ( MCV < 80)
  3. MHC - decreased
  4. MCHC - decreased

Iron deficiency anemia leads to a decreased production of heme –> decreased hemoglobin, hematocrit, MHC, and MCHC. Less hemoglobin means RBC precursor cells undergo one extra cell division –> microcytosis.

47
Q

What is the imperfection seen in RBCs of patients with asplenia?

A

Howell-Jolly Bodies

Howell-Jolly bodies are remnants of nuclear DNA from RBC precursor cells. These are removed in the spleen.

48
Q

What does MCV measure?

A

Mean corpuscular volume measures the size of RBCs to determine if they are normo-, micro-, or macrocytic

49
Q

A 25-year-old asymptomatic woman presents for her insurance physical exam. A routine CBC shows a hemoglobin of 11.6 g/dL and hematocrit of 35%. Her remaining lab findings are unremarkable. A peripheral smear shows an increased number of polychromatic forms, which is confirmed by her reticulocyte count of 4.6%. What is the most likely cause of anemia?

A. Aplastic anemia

B. Acute myeloid leukemia

C. Blood loss related to menses

D. Sickle cell disease

A

C. Blood loss related to menses

Aplastic anemia would cause low platelets and WBC count

AML would cause elevated WBCs and immature cells

50
Q

A 12-year-old girl has the following hemoglobin electrophoresis results: HbA = 56%, HbS = 40%, HbA2 = 3%, and HbF = 1%. This patient has:

A. No functional spleen

B. Sickled cells in the peripheral smear

C. Frequent blood transfusions

D. An increased risk of renal medullary carcinoma

E. Iron overload

A

D. An increased risk of renal medullary carcinoma

The patient’s electrophoresis results show that she has less than 50% HbS, meaning that she is asymptomatic and is a carrier of sickle cell trait. Sickle cell trait increases risk of renal medullary carcinoma

51
Q

A 65-year-old man comes in for colonoscopy. A CBC shows abnormal findings. A peripheral smear shows the following. Which of the following laboratory values would you expect to find?

A. Elevated lead level

B. Elevated MCV

C. Elevated RBC count

D. Low MCHC

E. Low RDW

A

B. Elevated MCV

The peripheral smear shows a hypersegmented neutrophil, which indicates a megaloblastic anemia. Megaloblastic anemia is caused by B12/folate deficiency and leads to an increased MCV

52
Q

Which type of megaloblastic anemia (B12 or folate deficiency) causes neurologic symptoms?

A

Vitamin B12 deficiency

B12 is required to convert methylmalonic acid into succinyl CoA.

Buildup of methylmalonic acid in spinal cord causes myelin degeneration and CNS damage.

53
Q

What are the 2 main causes of anemia in terms of RBCs?

A
  1. Increased destruction of RBCs
  2. Decreased production of RBCs
54
Q

What causes hemoglobin C disease and what is a common finding with this disease on a peripheral smear?

A

Glu –> Lys substitution of beta-globin gene

Common finding: hemoglobin C crystals

55
Q

What is cold autoimmune hemolytic anemia and what common clinical finding do patients with this disease have?

A

IgM that binds RBCs and fixes complement at temperatures below 30oC.

This causes agglutination of RBCs –> Raynaud’s phenomenon

56
Q

What is mean cell hemoglobin concentration (MCHC)?

A

The average amount of hemoglobin in RBCs of a given concentration.

Block 8 - Autoimmunity, Neoplasia, and Hematologic Disease (20 decks)

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