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Disease Mechanisms > Ch 14: Red Blood Cells and Bleeding Disorders > Flashcards

Ch 14: Red Blood Cells and Bleeding Disorders Flashcards

1
Q

what are the three main components of blood

A

formed elements, Buffy coat, and plasma

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2
Q

formed elements make up what percentage of blood

A

45%

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3
Q

buffy coat makes up what percentage of blood

A

<1%

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4
Q

plasma makes up what percentage of blood

A

55%

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5
Q

what are the three components of plasma and what are their percentages

A

water - 91%
proteins - 7%
other solutes - 2%

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6
Q

what are the two components of the Buffy coat and what are their percentages

A

platelets - <1%
leukocytes - <1%

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7
Q

what is the main component of formed elements in the blood and what is its percentage

A

erythrocytes (red blood cells) - >99%

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8
Q

what are the four proteins found in plasma

A

albumin
globulin
fibrinogen
prothrombin

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9
Q

what is the most important protein in plasma

A

albumin

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10
Q

what are 4 other solutes in plasma

A

ions
nutrients
waste products
gases

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11
Q

what are the 5 types of leukocytes in the Buffy coat

A

neutrophils
lymphocytes
monocytes
eosinophils
basophils

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12
Q

what are the three types of granulocytes

A

neutrophils
eosinophils
basophils

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13
Q

what are the two types of agranulocytes

A

lymphocytes
monocytes

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14
Q

what is hematocrit

A

percentage of blood (by volume) composed of red blood cells

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15
Q

what is the normal hematocrit in males

A

40-50%

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16
Q

what is the normal hematocrit in females

A

36-44%

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17
Q

what do all blood cells come from and where are they found

A

hemopoietic (pluripotent) stem cells (HSC) which are found in the bone marrow

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18
Q

hemopoietic (pluripotent) stem cells differentiate into which two lineages

A

lymphoid and myeloid stem cells

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19
Q

lymphoid stem cells differentiate into which 3 blood cells

A

natural killed cells
B cells
T cells

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20
Q

myeloid stem cells differentiate into which 4 precursor blood cells

A

myeloblast
monoblast
megakaryoblast
erythroblast

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21
Q

what 3 types of blood cells do myeloblasts differentiate into

A

neutrophils
eosinophils
basophils

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22
Q

monoblasts differentiate into which type of blood cells

A

monocyte

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23
Q

megakaryoblasts differentiate into which type of cell

A

platelets

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24
Q

erythroblasts differentiate into which type of cell

A

erythrocytes (red blood cells)

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25
Q

what does the suffix “blast” refer to

A

an immature cell

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26
Q

what percentage of red bone marrow space in adults is involved in hematopoiesis

A

50%

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27
Q

normal bone marrow contains what 4 things and their percentages

A

granulocytes - 60%
erythroid (erythrocyte precursor) - 20%
lymphocytes and monocytes - 10%
unidentified cells - 10%

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28
Q

what is hematopoiesis

A

development of blood cells

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29
Q

what percentage of granulocytes are stored vs functional

A

50% stored
50% functional

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30
Q

what percentage of thrombocytes are stored vs functional

A

30% stored
70% functional

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31
Q

what percentage of erythrocytes (red blood cells) are stored vs functional

A

0% stored
100% functional

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32
Q

what are three main storage sites of granulocytes

A

liver
spleen
bone marrow

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33
Q

what is erythropoiesis

A

development of red blood cells

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34
Q

what is erythropoietin

A

hormone released by the kidneys that stimulates maturation of erythrocytes

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35
Q

what is the normal shape of an erythrocyte

A

biconcave disk

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36
Q

what is happening during the late stage of an erythroblast

A

nucleus shrinks and is ejected out of the cell along with other organelles

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37
Q

what is happening during the reticulocyte phase of an erythroblast

A

remaining organelles are rejected
cell enters blood stream in its biconcaved disk form

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38
Q

what are 4 things that trigger the kidneys release of erythropoietin

A

decrease in red blood cells
decrease in hemoglobin synthesis
decrease in blood flow
hemorrhage

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39
Q

how long does it take reticulocytes to mature in the blood to become red blood cells

A

1-2 days

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40
Q

what is the normal percentage range of reticulocytes in the blood

A

0.5-1.5%

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41
Q

what is hemoglobin

A

large oxygen binding protein

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42
Q

what is the structure of hemoblogin

A

4 polypeptide subunits; 2 alpha and 2 beta chains
each polypeptide is bound to a heme group

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43
Q

what is a heme group

A

iron containing compound found on a hemoglobin molecule
4 in each hemoglobin molecule

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44
Q

what is Fe2+

A

ferrous iron
form that can bind to oxygen

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45
Q

what is Fe3+

A

ferric iron
form that cannot bind to oxygen

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46
Q

what happens when oxygen binds to a heme group on a hemoglobin molecule

A

the iron attached to the heme becomes oxidized and forms a red molecule called oxyhemoglobin (HbO2)

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47
Q

what is oxyhemoglobin (HbO2)

A

hemoglobin that has oxygen bound to its heme groups

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48
Q

what is deoxyhemoglobin

A

hemoglobin that does not have oxygen bound to its heme groups

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49
Q

how is methemoglobin formed

A

when hemoglobin releases its oxygen into the tissues, it can become oxidized to form methemoglobin (Fe3+)

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50
Q

what is a normal percentage of methemoglobin in the blood

A

<1%

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51
Q

what is methemoglobin reductase

A

enzyme that reactivates hemoglobin by reducing Fe3+ back to Fe2+

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52
Q

what is methemoglobulinemia and what are its two causes

A

excess methemoglobin and a decreased ability to deliver oxygen to the tissues
two causes: deficiency in methemoglobin or toxic insult

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53
Q

what is toxic insult of methemoglobinemia

A

some kind of toxin leads to high levels of methemoglobin
leads to brown appearance of blood

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54
Q

what are the three treatments for methemoglobinemia

A

treated with: methylene blue, vitamin C, or giving blood

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55
Q

what are the three things those with methemoglobinemia present with

A

presents with: headache, lightheadedness, and dyspnea

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56
Q

what is carboxyhemoglobin and how is it formed

A

complex of hemoglobin and carbon monoxide (CO)
CO changes shape of hemoglobin making it unable to unload oxygen into tissue

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57
Q

where are the three main storage locations of iron

A

liver cells
spleen macrophages
bone marrow macrophages

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58
Q

where is iron first absorbed within the body

A

duodenum

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59
Q

what transports iron throughout the plasma and where is it made

A

the glycoprotein transferrin which is made in the liver

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60
Q

where is iron lost at a rate of 1-2mg/day

A

lost in the skin, gut, and endometrium

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61
Q

what three things destroy old RBC

A

macrophages of the bone marrow, spleen, and liver

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62
Q

how long do red blood cells live before they’re destroyed

A

120 days

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63
Q

explain how red blood cells are destroyed

A

RBC become trapped in the sinusoids of the spleen and spleen macrophages digest them

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64
Q

what happens to hemoglobin after a red blood cell is destroyed

A

it is broken down into amino acids, iron, and bilirubin

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65
Q

what happens to bilirubin after a red blood cell is destroyed

A

it is excreted in feces and urine

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66
Q

what happens to iron and amino acids after a red blood cell is destroyed

A

they are recycled in the bone marrow to make new hemoglobin

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67
Q

what is anemia

A

reduction of the total circulating red cell mass below normal limits
leads to hypoxia because there are less RBC available to carry oxygen

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68
Q

what three things do those with anemia present with

A

progressive weakness (fatigue)
pallor
dyspnea (labored breathing)

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69
Q

what are the two things that are used to diagnosis anemia

A

hematocrit and hemoglobin concentration

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70
Q

what is macrocytic-normochromatic anemia

A

a type of anemia that is caused by impaired maturation of erythroid precursors in bone marrow
leads to a large but normal colored RBC

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71
Q

what is an example of macrocytic-normochromic anemia

A

pernicious anemia

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72
Q

what is microcytic-hypochromic anemia

A

a type of anemia that is cause by disorders of hemoglobin synthesis
leads to a small and very pale red blood cell

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73
Q

what are two examples of microcytic hypochromic anemia

A

iron deficiency; thalassemia

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74
Q

what is normocytic-normochromic anemia

A

a type of anemia caused by diverse etiologies (origins)
leads to a normal sized and color red blood cell

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75
Q

what is an example of normocytic-normochromic anemia

A

aplastic anemia

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76
Q

what are the three main mechanisms of classifying anemia

A

blood loss
increased red cell destruction (hemolysis)
decreased red cell production

77
Q

what is acute blood loss

A

loss of intravascular blood volume and all its components due to trauma
causes an increase in reticulocyte counts and eventually cardiovascular collapse or death

78
Q

what is chronic blood loss

A

loss of blood that induces anemia with it exceeds regenerative capacity of bone marrow or when iron reserves are depleted
caused by GI lesions or GYN disturbances

79
Q

what is hemolytic anemia and what are the three things its characterized by

A

accelerated destruction of red blood cells
characterized by:
shortened RBC life span
accumulation of hemoglobin degradation products
elevated erythropoietin and erythropoiesis levels

80
Q

what is extravascular hemolysis

A

destruction of RBCs outside of the blood vessels
alterations make RBC less deformable making them get stuck in the spleen
spleen macrophages destroy the cells, leading to anemia, splenomegaly, and jaundice

81
Q

what are two examples of extravascular hemolysis

A

hereditary spherocytosis and sickle cell anemia

82
Q

what is intravascular hemolysis

A

destruction of RBCs within the vessel
caused by mechanical injury, complement, parasites, or toxins
RBC is lysed, hemoglobin is released and binds to haptoglobin to form complex
complex is cleared by phagocytes which leads to anemia, jaundice, and hemoglobinemia

83
Q

what is the consequence of intravascular hemolytic anemia

A

haptoglobin that was bound to hemoglobin is removed by mononuclear phagocytes
lack of haptoglobin allows hemoglobin to oxidize to methemoglobin
too much methemoglobin reduces oxygen levels in the blood

84
Q

what is an acquired genetic defect that leads to increased red cell destruction (hemolysis)

A

antibody mediated destruction

85
Q

what is warm autoimmune hemolytic anemia
-causes
-intravascular vs extravascular

A

most common type of immunohemolytic anemia
IgG binds to Rh antigens on RBC at 37 degrees Celsius (normal body temperature)
50% primary (idiopathic)
50% secondary to things like lymphomas, SLE, and chronic lymphocytic leukemia (CLL)
destruction is mostly extravascular

86
Q

what is cold agglutinin autoimmune hemolytic anemia
-which conditions is it most seen
-intravascular vs extravascular

A

type of immunohemolytic anemia
IgM binds to RBC at cold temps (0-4 degrees celsius)
binding causes agglutination of seen mostly in fingers, toes, and ears and can lead to gangrene
can appear following infections like mycoplasma, EBV, CMV
IgM releases RBC once temperature increases
destruction is mostly extravascular

87
Q

what is cold hemolysin autoimmune hemolytic anemia
-in what conditions is it most seen
-intravascular or extravascular

A

type of immunohemolytic anemia
IgG autoantibodies bind to P blood group antigen in peripheral regions of the body when cold
RBC is destroyed once body warms up
often seen in children following viral infections
destruction is mostly intravascular

88
Q

what are the two main types of acquired, extrinsic, genetic defects that cause antibody mediated destruction of RBC and therefore anemia

A

immunohemolytic
drug induced hemolytic

89
Q

what is the hapten model of drug-induced hemolytic anemia

A

drug like penicillin binds to red blood cells
body now views RBC as foreign and creates antibodies against the drug
leads to hemolysis by complement or phagocytosis

90
Q

what is the immune complex formation of drug-induced hemolytic anemia

A

drug like quinidine binds to a carrier protein
antibodies against drug bind to this quinidine/carrier protein complex
complex binds to C3b receptors on RBC
RBC is now seen as foreign and is destroyed by complement

91
Q

what is the autoimmune model of drug-induced hemolytic anemia

A

body makes antibodies against drugs such as alpha-methydopa
antibodies mistakenly bind to RBC and cause it to be destroyed by phagocytosis

92
Q

how is drug-induced hemolytic anemia treated

A

remove offending drug
splenectomy

93
Q

what are the two types of intrinsic, inherited genetic defects that cause hemolytic anemia

A

RBC membrane disorders
enzyme deficiencies

94
Q

what is hereditary spherocystosis (HS)

A

type of RBC membrane disorder
75% of cases are autosomal dominant
mutations affect RBC membrane skeleton
hereditary spherocyte cells lose membranes as they age which lead to a spherocyte shape
can’t deform as they go through vessels as well which causes them to be removed through an extravascular process (spleen macrophages)
only live 10-20 days
presents with: anemia and splenomegaly

95
Q

what four things in the RBC membrane are most commonly mutated in hereditary spherocytes

A

ankyrin
band 3
spectrin
band 4.2
all lead to pieces of RBC being cleaved until it is sphere shaped and destroyed by splenic macrophage

96
Q

what is a glucose-6-phosphate-dehydrogenase deficiency (G6PD)

A

inherited, intrinsic enzyme deficiency
X-linked recessive disorder where there are mutations that destabilize G6PD enzyme
enzyme can no longer neutralize compounds like hydrogen peroxide, making RBC more susceptible to oxidative injuries
damaged cells will be lysed, leading to anemia

97
Q

what is the glucose-6-phosphate-dehydrogenase (G6PD) variant seen in american blacks

A

G6PD-

98
Q

what is the glucose-6-phosphate-dehydrogenase (G6PD) variant seen in mediterraneans

A

G6PD

99
Q

what are the 3 triggers of glucose-6-phosphate-dehydrogenase deficiency (G6PD)

A

infections (viral and pneumonia)
drugs (sulfonamide and nitrofurantoin)
foods (fava beans)

100
Q

explain how deficiency of glucose-6-phosphate-dehydrogenase (G6PD) enzyme damages RBCs are how they are removed after 2-3 days

A

deficiency of enzyme leads to high oxidant build up which damages RBCs by cross-linking globin chains (intravascular)
cross-linking leads to denaturing of red cell and formation of heinz bodies
heinz bodies get trapped in spleen, form bite cells and spheryocytes, and are removed by macrophages (extravascular)

101
Q

what does glucose-6-phosphate-dehydrogenase (G6PD) deficiency protect you from

A

RBC’s without enough glucose-6-phosphate-dehydrogenase impair the growth of plasmodium falciparum malaria

102
Q

what is the most common type (98%) of hemoglobin in normal adults

A

HbA (alpha 2, beta 2)

103
Q

what is the second most common type (2%) of hemoglobin in normal adults

A

HbA2 (alpha 2, delta 2)

104
Q

what is the fetal hemoglobin

A

HbF (alpha 2, gamma 2)

105
Q

what is the sickle hemoglobin

A

HbS (alpha 2, beta 2 s)

106
Q

which type of hemoglobin is elevated 4-8% in those with beta-thalassemia

A

HbA2 (alpha 2, delta 2)

107
Q

what is significant about hemoglobin production at the chromosomal level

A

alpha globin comes from alpha gene on chromosome 16 which is turned on during embryonic development - you get 2 from mom and two from dad
beta globin comes from beta gene on chromosome 11 - you get two from mom and two from dad

108
Q

which type of hemoglobin is elevated in those with beta-thalassemia trait

A

HbA2 (2 alpha, 2 delta)

109
Q

what is the mechanism of thalassemia syndromes

A

mutation in globin genes leads to decrease synthesis of alpha or beta chains
chains are damaged by precipitants

110
Q

what are three consequences of thalassemia syndromes

A

anemia, hypoxia, and red cell hemolysis

111
Q

why do thalassemia syndromes cause anemia

A

decreased production of hemoglobin leads to decreased life span of RBCs and therefore anemia

112
Q

what causes A-Thalassemia

A

inherited deletions reduced or stop synthesis of alpha-globin chains

113
Q

what causes B-thalassemia

A

mutations lead to diminished synthesis of B-globin chains
Bdegree: no beta chain synthesis at all
B+: decreased beta chain synthesis

114
Q

what do the RBCs of thalassemia syndromes looks like

A

microcytic-hypochromic due to decreased hemoglobin synthesis

115
Q

what is B-thalassemia major (Cooley’s anemia) and what treatment does it require

A

severe case of reduced beta globin
require blood transfusions

116
Q

what’s another name for B-thalassemia major

A

Cooley’s anemia

117
Q

what is B-thalassemia major caused by

A

point mutations that lead to defects in transcription, splicing, or translation of B-globin mRNA

118
Q

what is B-Thalassemia intermedia and what treatment does it require

A

severe cases of reduced beta globin
do not require regular blood transfusions

119
Q

what do those with B-thalassemia minor or trait present with

A

asymptomatic with mild or absent anemia
red cell abnormalities seen

120
Q

what type of thalassemia is silent carrier and what does it present with

A

type of a-thalassemia
asymptomatic with no red cell abnormalities

121
Q

what is silent carrier a-thalassemia caused by

A

mainly gene deletions

122
Q

what do those with a-thalassemia trait present with

A

asymptomatic with mild or absent anemia
red cell abnormalities seen

123
Q

what type of thalassemia is HbH disease, how bad is it, and how is it treated

A

type of A-thalassemia
severe
does not require blood transfusions

124
Q

what happens to those with a-thalassemia major

A

aka hydrops fetalis
lethal in utero without transfusions

125
Q

what is another name for a-thalassemia major

A

hydrops fetalis

126
Q

how does B-thalassemia affect your heart and liver

A

erythroblasts of those with B-thalassemia are abnormal and therefore can’t be made into red blood cells so they die in the bone marrow
less RBCs means there are less places for the absorbed iron to go
unabsorbed iron causes overload in the heart and liver leading to secondary hemochromatosis

127
Q

what is another term for the systemic iron overload of the heart and liver

A

secondary hemochromatosis

128
Q

how does B-thalassemia affect your skeleton

A

erythroblasts of those with B-thalassemia are abnormal and therefore can’t be made into red blood cells so they die in the bone marrow
reduced number of RBCs leads to anemia, tissue hypoxia, and erythropoietin increase
increased erythropoietin leads to bone marrow expansion and therefore skeletal deformities

129
Q

what happens to the abnormal erythroblasts that are not destroyed in the bone marrow in those with B-thalassemia

A

the hypochromic cell with a-globin aggregate gets lysed in the spleen
reduced RBCs leads to anemia, tissue hypoxia, and erythropoietin increase
increased erythropoietin leads to bone marrow expansion and therefore skeletal deformities

130
Q

what is sickle cell anemia

A

autosomal recessive disorder where there is a point mutation in B-globin chain
glutamic acid is replaced with valine
sickled hemoglobin can carry oxygen but once they drop oxygen off, they become deoxygenated and sickled
deoxygenated hemoglobin forms long polymers that distort the RBC
lifespan of RBC is reduced significantly

131
Q

what percentage of African Americans are heterozygous for sickle cell anemia

A

8-10%

132
Q

what does it mean when you’re heterozygous for HbS

A

you have sickle cell trait and are most of the time asymptomatic

133
Q

what does it mean when you’re homozygous for HbS

A

you will be symptomatic

134
Q

in someone with heterozygous sickle cell trait, what percentage of their hemoglobin is HbS vs HbA

A

HbS: 40%
HbA: 60%

135
Q

in someone with homozygous sickle cell, what percentage of their hemoglobin is HbS vs HbA

A

all is HbS

136
Q

explain the mechanism which causes a cell to become sickled

A

point mutation in B-globin gene switches out a glutamic acid for valine
when RBCs drop off their oxygen, the deoxygenated cell forms long polymers, sickling the cell

137
Q

what are the four factors that affect the rate and degree of sickling

A

interaction of HbS with other types of hemoglobin in cell
mean cell hemoglobin concentrations
intracellular pH
transit time of red cells through microvascular beds

138
Q

what happens to the mean hemoglobin concentration if the cells are dehydrated

A

increase in concentration of hemoglobin which increases amount of sickling

139
Q

how does the intracellular pH affect the rate and degree of sickling

A

decreased intracellular pH reduces affinity of O2
O2 won’t stick well which leads to deoxygenation

140
Q

how does the transit time of RBCs through microvascular beds affect rate and degree of sickling

A

longer the transit time, the more sickling that happens in spleen, bone marrow, and inflamed vessels

141
Q

what are three complications of sickle cell anemia

A

episodic vessel blockage (tissue infarction of bone marrow and spleen)
repeated bouts of sickling lead to permanent RBC membrane damage, eventually leading to anemia
autosplenectomy

142
Q

what is autosplenectomy

A

seen in sickle cell anemia
erythrostasis in spleen (red blood cells get stuck in spleen)
leads to infarction and fibrosis of spleen with eventual shrinkage

143
Q

what does sickle cell anemia protect you from

A

plasmodium falciparum malaria

144
Q

how is sickle cell anemia treated

A

hydration
blood transfusions
hydroxyurea

145
Q

what is hydroxyurea used for and what does it do

A

used to treat sickle cell anemia
inhibits DNA synthesis
increases HbF levels
anti-inflammatory

146
Q

what is aplastic anemia

A

chronic primary hematopoietic (bone marrow) failure which leads to pancytopenia
can present with anemia, leukopenia (neutropenia), and thrombocytopenia
onset is gradual
cells are normochromic, normocytic

147
Q

what is pancytopenia

A

low levels of RBCs, WBCs, and platelets typically caused by an issue with the bone marrow

148
Q

what is the major acquired cause of aplastic anemia (with percentage)

A

idiopathic (cause unknown) - 60% of all cases

149
Q

what is the most common chemical agent cause of aplastic anemia

A

idiosyncratic (distinct) chemicals

150
Q

what is a major physical agent that causes aplastic anemia

A

viral infections

151
Q

what are two major inherited conditions that cause aplastic anemia

A

fanconi anemia
telomerase defects

152
Q

what is the extrinsic pathogenesis of aplastic anemia

A

immune-mediated suppression of bone marrow progenitors (antibodies destroy cells)
cells aren’t being made

153
Q

what is the intrinsic pathogenesis of aplastic anemia

A

mutation within stem cells stops them from acting correctly
can be caused by things like being exposed to a virus

154
Q

give an example of intrinsic pathogenesis of aplastic anemia

A

pluripotent stem cell is affected by environmental insult such as virus or drug that alters stem cells
altered stem cells express new antigens which activates T cells to destroy them
or
reduces proliferative and differentiate capacity
both lead to marrow aplasia

155
Q

how is aplastic anemia diagnosed and what does it show

A

through bone marrow biopsy
shows lots of adipocytes with little cellular components

156
Q

how is aplastic anemia treated

A

avoidance of toxin
blood transfusion
stimulation of hematopoiesis
stem cell transplantation

157
Q

what is fanconi anemia

A

type of aplastic anemia caused by inherited genetic defect
autosomal recessive
destroyed multiprotein complex that is required for DNA repair
affects bone marrow in early life
leads to underdeveloped kidneys and spleen
leads to bone abnormalities in thumbs or radii

158
Q

what are telomerase defects

A

inherited cause of aplastic anemia
mutation of telomerase enzyme which results in premature hematopoietic stem cell exhaustion and marrow aplasia
stem cells die without the telomerase enzyme

159
Q

what are Vitamin B12 and Vitamin B9 deficiencies associated with

A

anemia of diminished erythropoiesis
both are coenzymes are required for synthesis of thymidine
presents with macrocytic-normochromic cells

160
Q

what is vitamin B12

A

cobalamin

161
Q

what is vitamin B9

A

folic acid

162
Q

what is the mechanism of vitamin deficiency causing anemia

A

vitamin deficiencies lead to inadequate synthesis of thymidine and defective DNA replication
leads to enlarged abnormal hematopoietic precursors
megaloblasts in bone marrow have lots of hemoglobin and RBCs are large

163
Q

what is the outcome of someone with anemia caused by nutritional deficiencies

A

marrow hyperplasia leads to most cells undergoing apoptosis
overall leads to pancytopenia

164
Q

vitamin B12 deficiency can be caused by impaired absorption which will lead to what

A

pernicious anemia

165
Q

what three major things lead to a vitamin B9 deficiency

A

decreased intake (alcoholics, poor, elderly)
increased requirement (pregnancy, cancer)
impaired utilization (antagonist drugs)

166
Q

what is pernicious anemia caused by

A

type of megaloblastic anemia
autoimmune gastritis causes impaired production of intrinsic factor which leads to impaired absorption of vitamin B12

167
Q

what is intrinsic factor

A

secreted by parietal cells of fundic mucosa
required for proper absorption of vitamin B12

168
Q

what is autoimmune (chronic atrophic) gastritis

A

cause of pernicious anemia
inflammation of the stomach due to auto reactive T cells attacking gastric mucosa
or
H. pylori infection
both lead to formation of autoantibodies that attack parietal cells and therefore no intrinsic factor can be produced

169
Q

how is the CNS involved in pernicious anemia

A

demyelination of dorsal and lateral tracts lead to loss of axon
causes sensory neuropathy and visual impairment

170
Q

how is pernicious anemia diagnosed

A

through symptoms and low vitamin counts in the blood

171
Q

how is pernicious anemia treated

A

with vitamin B12 injections

172
Q

what is folic acid (vitamin B9) deficiency anemia

A

some factor leads to folic acid deficiency
it’s required for DNA synthesis - makes thymidine
does not cause neurologic impairment
treated with oral folic acid

173
Q

what is iron deficiency anemia (hypoferremia) including cell type

A

most common type of anemia in the world
microcytic-hypochromic cells due to insufficient hemoglobin synthesis
caused by dietary deficiency, chronic blood loss, impaired absorption, and increased requirement
don’t present until levels are super low because you use all your store

174
Q

how much iron is functional and where is it found

A

80%
found in hemoglobin, myoglobin, and iron containing enzymes

175
Q

what are two types of iron containing enzymes

A

cytochrome and catalase

176
Q

how much iron is stored and where is it stored

A

20%
stored as hemosiderin or bound to ferritin in the liver, mononuclear phagocytes in bone marrow, and spleen

177
Q

how does hepcidin normally work

A

works to block ferroportin 1 from allowing iron absorption into bloodstream

178
Q

what is the effect of low iron stores on hepcidin

A

low iron store leads to less plasma hepcidin which increases activity of ferroportin 1, allowing iron to be absorbed

179
Q

what is myelophthisic anemia

A

type of space-occupying marrow lesion
bone marrow is being replaced and pushed out of the way due to lesions
immature, tear drop shaped cells released
usually caused by metastatic cancer

180
Q

what are the three most common types of metastatic cancer which causes myelophthisic anemia

A

breast
lung
prostate

181
Q

what is polycythemia

A

abnormally high levels of RBC with lots of hemoglobin

182
Q

what’s a relative cause of polycythemia

A

dehydration leads to decreased plasma volume and increased hemoconcentration

183
Q

what’s absolute polycythemia

A

increase of total red cell mass
two types: primary and secondary

184
Q

what is primary absolute polycythemia

A

excess red blood cells due to an abnormality of stem cells in bone marrow
happens even with low erythropoietin levels

185
Q

what are two types of primary absolute polycythemia

A

polycythemia vera (red cells grow in the bone marrow, no erythropoietin needed)
familiar EPO receptor gain of function mutation (continuous activation)

186
Q

what is secondary absolute polycythemia

A

increased EPO secretion either from tumors
or
inherited defects in renal oxygen-sensing pathways which stimulates transcription of EPO gene

187
Q

which carcinomas produce erythropoietin

A

renal cell carcinomas

188
Q

what is Chuvash polycythemia

A

rare inherited defects in renal oxygen sensing pathways
stimulates transcription of EPO gene

Disease Mechanisms (19 decks)

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