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SP15 Pathology > Exam 2; Red Blood Cell Disorders > Flashcards

Exam 2; Red Blood Cell Disorders Flashcards

1
Q

This is the reduction in red cell mass with consequent decrease in oxygen transport

A

anemia

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2
Q

Anemia can cause impaired tissue oxygenation, which can lead to what for clinical symptoms

A

shortness of breath
weakness
fatigue
pallor

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3
Q

In which ways can anemia develop

A

RBC loss
decreased RBC survival
decreased RBC production

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4
Q

What are three laboratory tests that can be used to test for anemia

A 
CBC
blood smear review
reticulocyte count
iron indices
hemolysis work-up
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5
Q

A young, healthy individual can tolerate up to how much rapid blood loss with minimal symptoms

A

1000ml

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6
Q

Rapid blood loss of this, in a young healthy individual produces shock

A

2000ml

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7
Q

Once blood loss is controlled, what occurs

A

interstitial fluid redistributes to re-expand vascular volume

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8
Q

How does chronic hemorrhage cause anemia

A

when the rate of loss exceeds the capacity for RBC regeneration or when iron reserves are depleted

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9
Q

This is the destruction of red cells within the circulation

A

intravascular hemolysis

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10
Q

This is the destruction of red cells within the reticuloendothelial system; spleen and liver

A

extravascular hemolysis

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11
Q

Chronic hemorrhage is typically secondary to what

A

chronic bleeding in the GI or menorrhagia that eventually leads to iron deficiency

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12
Q

This is a key feature in intravascular hemolysis

A

decrease in serum haptoglobin (hemoglobin carrying protein)
the free hemoglobin is excreted in the urine of which is toxic to the kidney and the iron is lost in the urine
heme is converted to bilirubin which leads to hyperbilirubinemia and jaundice

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13
Q

Intravascular hemorrhage can be caused by what two mechanisms

A

immune; transfusion reaction

non-immune; mechanical trauma

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14
Q

What are three extrinsic defects that are immune related that can lead to extravascular hemolysis

A

autoimmune
erythroblastosis fetalis
transfusion reason

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15
Q

What are three intrinsic effects that are non-immine related that can cause extravascular hemolysis

A

RBC membrane defects
hemoglobinopathies
metabolic defects

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16
Q

What is characteristics of extravascular hemolysis

A

damaged/abnormal RBC are removed in the slpeed where it is broken down. Free hemoglobin is not released directly into the blood or urine but the breakdown products have increased (hyperbilirubinemia and jaundice)

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17
Q

This may occur due to extravascular hemolysis

A

hepatosplenomegaly; due to the buildup of RBC byproducts and removal

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18
Q

What is the difference between intrinsic and extrinsic effects that cause hemolysis

A

intrinsic - usually inherited

extrinsic - acquired abnormalities

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19
Q

This intrinsic defect which causes hemolytic anemia is an abnormality of spectrin, a structural protein of the RBC cytoskeleton

A

hereditary spherocytosis

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20
Q

How does hereditary spherocytosis cause hemolytic anemia

A

the RBCs are less deformable and can’t squeeze through the splenic sinusoids, thus are sequestered and destroyed by the spleen

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21
Q

How does removal of the spleen aid hereditary spherocytosis

A

it results in normal red cell survival but not in normal morphology; the cells remain as spheres

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22
Q

What is the genetics behind sickle cell anemia, and intrinsic defect

A

hemoglobin S; single base pair amino acid substitution (valine for glutamic acid) at position 6 of the beta chain, but those affected are resistant to malaria

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23
Q

When does a sickle cell in SCA form

A

low oxygen tension induces hemoglobin S polymerization

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24
Q

What becomes of sickle cells

A

they are prone to splenic sequestration

can also becomes trapped in the microcirculation; leading to ischemia/infarction

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25
Q

What are the two leading causes of ischemia-related death in sickle cell anemia patients

A

actue chest syndrome

stroke

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26
Q

How severe is anemia is sickle cell patients

A

moderate to severe

27
Q

What are the clinical symptoms of sickle cell anemia

A

typically asymptomatic - less than half of hemoglobin is sickled
hyperbilirubinemia
reticulocytosis
“autosplenectomy”

28
Q

This intrinsic defect (extravascular hemolysis) is a quantitative defect (point mutation/gene deletion) in the synthesis of alpha or beta global chains leading to anemia and ineffective erythropoiesis

A

Thalassemia

29
Q

What are the clinical manifestations of thalassemia

A

variable degrees of anemia - asymptomatic to severe
microcytic/hypochromic anemia
protective against malaria

30
Q

Which ethnic groups are more prone to sickle cell and thalassemia

A

sickle cell - african

thalassemia - mediterranean, african, southeast asian

31
Q

This is an inherited X-linked metabolic defect encountered primarily in african descent in which red blood cells are susceptible to oxidant injury by drugs or toxins or infections

A

glucose-6-phosphate deficiency

32
Q

How does G6P deficiency cause anemia

A

the denaturation of oxidized hemoglobin causes it to precipitate within the cell and attach to the RBC membrane, reducing the flexibility of the RBC leading to extravascular hemolysis

33
Q

What is the morphologic hallmark of G6P deficiency

A

“bite mark” cells

34
Q

This extrinsic defect occurs in utero and results from blood group incompatibility between the mother and the fetus due to RBC antigens from the father

A

erythroblastosis fetalis; hemolytic disease of the newborn

35
Q

How does erythroblastosis fetalis manifest

A

fetal RBCs enter the maternal circulation resulting in sensitization, maternal IgGs can cross the placenta resulting in extravascular hemolysis

36
Q

What are the most common antigens in erythroblastosis fetalis

A

ABO and Rh

37
Q

What is given to group O negative mothers to prevent erythroblastosis fetalis

A

anti-D, Rhogam is given to a mother Rh-negative who just gave birth to a Rh-positve child, of which then binds to the Rh-positive fetal cells and prevents the mother from generating a response

38
Q

Infants of this blood type are at risk of erythroblastosis fetalis

A

A and B infants of group O mothers

39
Q

What is the mechanism of hemolytic transfusion reaction

A

A transfusion of incompatible RBCs into a sensitized patient results in the binding of Ab to Ag complexes with the activation of complement and immediate intravascular hemolysis

40
Q

Which antigens are the most important regarding hemolytic transfusion reactions

A

ABO antigens

41
Q

What is the mechanism of autoimmune hemolysis

A

patient makes antibodies to their own RBCs
the antibody coated cells can be lysed (via complement) or removed by the reticuloendotheial system
has a positive direct Coomb’s test

42
Q

This is the hallmark of autoimmune hemolytic anemia

A

spherocytes

43
Q

This mechanical trauma causes intravascular hemolysis dude to RBC fragmentation by increased turbulence from abnormal cardiac valves

A

cardiac valve prosthesis

44
Q

This mechianical trauma causes intravascular hemolysis due to RBC lysing as they pass through fibrin clots/strands in the microcirculation

A

DIC

45
Q

These are the hallmark of hemolysis due to mechanical trauma

A

schistocytes (RBC fragments)

46
Q

These can infect RBCs and result in intravascular hemolysis

A

parasites (malaria)

47
Q

This is the most common basis of anemia worldwide; develops insidiously (gradually) in most cases

A

iron deficiency

48
Q

What are three mechanisms that could cause iron deficient anemia

A

inadequate intake
increased demands
increased loss
may be related to a more serious condition

49
Q

What is the clinical manifestation of RBCs affected by iron deficiency anemia

A

microcytoic, small

hypochromic, less hemoglobin

50
Q

What are the most common causes and result of megaloblastic anemia

A

folate and B12 deficiency, involved with the synthesis of thymidine this causes a delay in mitotic division, increasing nuclear size as cytoplasmic maturation proceeds normally resulting in an abnormally large red cells. These accumulate in the bone marrow and cause the release of too few RBCs

51
Q

What are the effects of megaloblastic anemia

A

abnormally large red and white cell precursors
decrease mature red cell production
if severe, platelet production can be affected
marked intramedullary red cell death

52
Q

This is found in fresh vegetables, the body stores are small and decreased dietary intake or malabsorption can affect this as well as increased requirements

A

folate deficiency

53
Q

This is present in animal foods, the body stores are large and can cause hematologic abnormalities as well as neurologic symptoms

A

B12 deficiency

54
Q

This is caused by autoantibodies to parietal cells and intrinsic factor
It is associated with B12 deficiency associate with atrophic gastritis as well as a loss of gastric parietal cells, achlorhydria, and deficient IF

A

pernicious anemia

55
Q

This is pancytopenia (deficiency in all blood cells) with markedly decreased bone marrow cellularity

A

aplastic anemia

56
Q

What are the causes of aplastic anemia

A

over half the cases are idiopathic

remainder are caused by either drugs, toxins, or viral hepatitis

57
Q

What are the two pathogenic theories of aplastic anemia

A

an acquired stem cell defect with decreased production of all blood cells
most cases involve suppression of stem cells by T-cells

58
Q

This is a successful treatment for aplastic anemia in patients <40

A

bone marrow transplant

59
Q

This is when bone marrow is replaced by a tumor or fibrosis, often see misshapen RBCs resembling “teardrops” on blood smear; platelets are also decreased

A

myelophthisic anemia

60
Q

This is an increase in red cell mass

A

polycythemia

61
Q

This type of polycythemia occurs with hemoconcentration from dehydration, vomiting, diarrhea, or excessive use of diuretics

A

relative polycythemia

62
Q

Stimuli which increases this, can produce secondary polycythemia, this is decreased/normal in primary polycythemia

A

erythropoietin

63
Q

This occurs when a non-regulated (neoplastic) proliferation of red cells and myeloid cells is called polycythemia vera

A

primary polycythemia

64
Q

What is the treatment of primary polycythemia

A

removal of excess RBC by phlebotomy

SP15 Pathology (17 decks)

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