Hematology Exam 7 (Anemias, Iron kinetics) Flashcards

1
Q

List the 3 iron compartments in the body and how much iron is held in each

A

Functional - 80% (hgb, myoglobin, enzymes)
Storage - 20% (ferritin and hemosiderin)
Transport - <1% (transferrin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

List the steps of the iron cycle to include what form of iron is in each stage

A

Iron ingested as heme
Absorbed through enterocytes of intestine as ferrous form
Can then be stored or transported to plasma for use
Must be in ferric form for transport in blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Function of ferroportin

A

transports ferrous iron from enterocyte into blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Function of hepcidin

A

protein made by hepatocytes that binds to and INACTIVATES FERROPORTIN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Function of hephaestin

A

protein that oxidizes iron turning ferrous iron (Fe2+) into ferric iron (Fe3+) for transport in the blood

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Function of transferrin

A

Binds ferric iron for transport in the blood (iron transporter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Function of erythroferrone

A

Used in the second mechanism for iron regulation - increased EPO will cause erythroferrone to be secreted which decreases hepcidin production to increase iron absorption in the intestine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Function of ferritin
What is apoferritin?

A

the major storage protein for iron
Apoferritin = ferritin not yet bound to iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Function of hemosiderin

A

Partially degraded ferritin; another storage form of iron (iron is less available in this form)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Function of haptoglobin

A

binds hemoglobin released from degraded RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Function of hemopexin

A

Binds heme released from degraded RBCs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does decreased iron stores affect hepcidin, ferroportin, and iron absorption?

A

Decreased iron stores = decreased hepcidin = activated ferroportion = increased iron absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How is iron homeostasis maintained?

A

Changes in hepcidin production

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How does increased iron stores affect hepcidin, ferroportin, and iron absorption?

A

Increased iron stores = increased hepcidin = inactivated ferroportin = decreased iron absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the serum iron test measuring and how?

A

Measures iron that had been bound to transferrin - iron released from transferrin by acid and measured spectrophotometrically

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does menstruation, lactation, and pregnancy, and growing children affect iron needs?

A

Increases iron needs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the TIBC test measuring and how?

A

This test is an indirect measure of transferrin. It measures how much iron could be bound if excess iron is added

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What Is the formula for the TSAT test? What is it measuring?

A

This is calculated by Serum iron/TIBC x 100 to get the % transferrin saturation. It measures how much transferrin in your body is actually bound to iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the prussian blue test measuring and how?

A

This test assesses body iron stores by staining tissues - dark blue granules present indicate iron stores (ferritin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is serum ferritin test measuring and how?

A

Immunoassay that indicates the levels of ferritin in your serum. Low ferritin levels = iron deficiency of some sort
These levels correlate with prussian blue results

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the sTfR test measuring? What do results indicate?

A

Amount of soluble transferrin receptors on cell membranes - increased sTfR with decreased iron indicates an iron deficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the hemoglobin content of reticulocytes test measuring and what do results indicate?

A

Measures hemoglobin content of reticulocytes - decreased when iron available for erythropoiesis is restricted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the ZPP test?

A

This is when zinc binds protoporphyrin IX instead of iron - will be increased when iron is not available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

sTfR/log ferritin levels and HGB content of retics for True Iron Deficiency (Thomas Plot)

A

True Iron deficiency (lower right quadrant) has increased sTfR/log ferritin and decreased HGB content of retics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
sTfR/log ferritin levels and HGB content of retics for Normal Iron Status (Thomas Plot)
Normal iron status (upper left quadrant) has normal HGB content of retics and normal sTfR/log ferritin
26
sTfR/log ferritin levels and HGB content of retics for Latent Iron Deficiency (Thomas Plot)
Latent Iron Deficiency (upper right quadrant) has increased sTfR/log ferritin and normal HGB content of retics
27
sTfR/log ferritin levels and HGB content of retics for Functional Iron Deficiency (Thomas Plot)
functional iron deficiency (lower left quadrant) has normal sTfR/log ferritin and decreased retic HGB
28
Define anemia
A decrease in oxygen carrying capacity of the blood due to decreased RBC count, HGB, and/or HCT levels
29
What is the normal HCT range for newborns? Men? Females and children?
Newborns: 48-66% Men: 40-54% Females and children: 35-49%
30
What Is the normal HGB range for newborns? Men? Females and children?
Newborns: 16.5-21.5 Men: 13.5-18 Females and children: 12-15
31
What is the normal RBC count for newborns? Men? Females and children?
Newborns: 4.1-6.1 Men: 4.2-6 Females: 3.8-5.2
32
What is the difference between insufficient erythropoiesis and ineffective erythropoiesis?
Insufficient = decreased number of RBC precursors/decreased RBC production (decreased production) Ineffective = defective RBC precursors produced (increased desruction)
33
What is the calculation for MCV and normal range?
HCT x 10/RBC count Normal range = 80-100 fL
34
What is the calculation for MCH and normal range?
HGB x 10/RBC count Normal range = 26-32 pg
35
What is the calculation for MCHC and normal range?
HGB x 100/HCT Normal range = 32-36 g/dL
36
What is the purpose of the reticulocyte count?
Assesses the bone marrow's ability to increase erythropoiesis to compensate for anemia
37
What is the purpose of the corrected reticulocyte count?
Corrects for the degree of anemia based on patient's HCT
38
What is the purpose of the reticulocyte production index (RPI)?
calculated to correct for a low HCT and the presence of shift reticulocytes (immature retics) that may falsely elevate the retic count
39
What is the normal reticulocyte count for adults vs newborns?
Adults: 0.5-2.5% Newborns: 1.5-6.0%
40
What information can the peripheral smear provide in the assessment of anemia?
It is the only way to determine poikilocytosis and RBC inclusions
41
What information can the bone marrow exam provide in the assessment of anemia?
Can see abnormal cellularity, evidence of ineffective erythropoiesis, lack of iron staining, and presence of tumor cells/fibrosis
42
What is a microcytic anemia and an example?
Anemias with MCV <80, small RBCs Example: iron deficiency anemia
43
What is a macrocytic anemia and an example?
Anemias with MCV >100, large RBCs Ex. megaloblastic anemias
44
What is a normocytic anemia and an example?
Anemias with MCV 80-100 Ex. Hemolytic anemia/aplastic anemia/blood loss anything due to decreased RBC production
45
What is the most common cause of IDA?
Excessive blood loss
46
List 4 causes of IDA and an example of each
Inadequate intake - diet Increased need - childhood/pregnancy Impaired absorption - celiac disease Chronic blood loss - chronic hemorrhage
47
Stage 1 of IDA
Storage Iron Depletion - loss of storage iron so ferritin levels drop but RBC production/development is normal. This stage is considered "latent iron deficiency"
48
Stage 2 of IDA (what is it called, what lab values are increased/decreased)
Transport Iron Depletion - there is exhaustion of storage pool at this point. Increased: TIBC, FEP, sTfRs Decreased: retic HGB (onset of iron restricted erythropoiesis), iron, ferritin, prussian blue stain shows NO stored iron Still considered latent iron deficiency because anemia is still not evident
49
Stage 3 of IDA
Functional iron depletion, Iron deficiency anemia. Increased: FEP, sTfRs, TIBC Decreased: H&H, storage and transport iron, HGB of retics RBCs are microcytic and hypochromic now First stage where anemia is evident
50
What group of people are at the highest risk for developing IDA?
Menstruating women, pregnant/nursing women, and growing children
51
What is an example of SCREENING tests for IDA and what would the values look like for a patient with IDA
CBC and peripheral smear - a patient with IDA would have anisocytosis (increased RDW = first sign), microcytosis, hypochromia
52
What is one of the first signs of a developing IDA?
Increased RDW (anisocytosis)
53
What are examples of DIAGNOSTIC tests for IDA and what would the values look like for a patient with IDA?
Iron studies such as TIBC (low), transferrin saturation (low), serum ferritin (low) and reticulocyte parameters (decreased retic count = diminished erythropoiesis)
54
What are examples of SPECIALIZED tests for IDA and what would the values look like for a patient with IDA?
FEP (increased), ZPP(increased), sTfRs(increased), BM exam will be hyperplastic and have a decreased M:E ratio
55
What is the central feature of ACI?
Sideropenia (low serum iron) despite abundant iron stores AKA functional iron deficiency
56
Causes of ACI
Impaired ferrokinetics Impaired erythropoeisis Shortened RBC lifespan
57
Population most affected by ACI
Hospitalized patients due to inflammatory conditions
58
What is the most important contributor to ACI?
Impaired ferrokinetics
59
What type of anemia is considered functional iron deficiency and why?
ACI - because iron stores are present but cannot be used because hepcidin levels are increased during inflammation which leads to decreased iron release from macrophage
60
What are the two acute phase reactants that are increased in ACI, causing functional iron deficiency?
Lactoferrin and hepcidin
61
Notable lab values in ACI
Normocytic, normochromic Decreased iron Decreased TIBC Ferritin falsely increased (acute phase reactant) Prussian blue stain shows abundant iron stores NORMAL sTfR
62
IDA vs ACI lab values
IDA has increased sTfRs, ACI has normal sTfRs
63
What is the hallmark finding in sideroblastic anemias?
Ringed sideroblasts
64
What is sideroblastic anemia?
Anemia resulting from interference of production of protoporphyrin
65
What is an example of an acquired form of sideroblastic anemia? Lab results?
Lead poisoning which interferes with protoporphyrin synthesis. Basophilic stippling is a classic finding in the peripheral smear, accumulated ALA in urine and increased FEP/ZPP
66
What is an example of a hereditary form of sideroblastic anemia?
Porphyrias - impaired heme synthesis with the accumulation of porphyrin and its precursors
67
What is hereditary hemochromatosis?
Mutations in genes (HFE gene) controlling proteins involved in iron kinetics leading to continually absorbed iron even when stores are full
68
What is hemochromatosis also called? Why?
Bronzed diabetes because it causes jaundice and diabetes
69
Lab diagnosis of hereditary hemochromatosis
Abnormal liver function tests Increased TSAT, ferritin, and iron
70
Iron Study Values for IDA (Iron, ferritin, TIBC, TSAT, sTfRs, FEP/ZPP, Prussian Blue)
Iron: decreased Ferritin: decreased TIBC: increased TSAT: decreased sTfRs: increased FEP/ZPP: increased Prussian Blue: no stained iron
71
Iron Study Values for ACI (Iron, ferritin, TIBC, TSAT, sTfRs, FEP/ZPP, Prussian Blue)
Iron: decreased Ferritin: increased TIBC: normal/decreased TSAT: normal/decreased sTfRs: normal/decreased FEP/ZPP: increased Prussian Blue: normal/increased
72
Iron Study Values for HH (Iron, ferritin, TIBC, TSAT, sTfRs, FEP/ZPP, Prussian Blue)
Iron: increased Ferritin: increased TIBC: normal/decreased TSAT: increased sTfRs: normal/decreased FEP/ZPP: normal Prussian Blue: increased stained iron
73
Iron Study Values for sideroblastic anemia (Iron, ferritin, TIBC, TSAT, sTfRs, FEP/ZPP, Prussian Blue)
Iron: increased Ferritin: increased TIBC: normal/decreased TSAT: increased sTfRs: normal/decreased FEP/ZPP: N/A Prussian Blue: ringed sideroblasts present
74
What is the etiology/underlying cause of megaloblastic anemias? What are the 2 deficiencies leading to these anemias?
Impaired DNA synthesis because of decreased cell divisions --> leads to large cells B12 and Folate deficiencies
75
How do B12 and Folate deficiencies lead to megaloblastic anemias?
Impaired nucleotide production for DNA synthesis, decreased thymidine availability, leads to ineffective erythropoiesis
76
Another name for B12
Cobalamin
77
What does no B12 lead to the buildup of?
MMA and homocysteine
78
Describe nuclear to cytoplasmic asynchrony. Why is this seen in megaloblastic anemias?
Nucleus is not maturing as fast as the cytoplasm. This is seen in megaloblastic anemias because there is impaired DNA synthesis (found in the nucleus) so it does not mature as fast as the cytoplasm, which has RNA in it.
79
Clinical presentations of B12 deficiency vs Folate deficiency
B12: neurologic symptoms that take years to develop Folate: can lead to neural tube defects such as spina bifida in pregnancies, takes a few months to develop
80
Causes of B12 and Folate deficiency
Inadequate intake (B12 found in meats and dairy while folate found in vegetables, beans, cereal, fruit) Impaired absorption
81
What is b12 bound to in normal absorption?
Intrinsic factor
82
What is pernicious anemia and how does it lead to megaloblastic anemia?
autoimmune disorder caused by impaired absorption of VITAMIN B12 due to an intrinsic factor deficiency
83
List notable lab findings of megaloblastic anemias
Macrocytosis, decreased H&H, oval macrocytes, MCV >120 fL, hypersegmented neutrophils
84
How can macrocytic nonmegaloblastic anemias be differentiated from a megaloblastic anemia?
Macrocytic anemias are not due to impaired DNA synthesis MCV rarely exceeds 120 fL Lack oval macrocytes and hypersegmented neutrophils May be normal (newborns) or due to pathological condition (liver disease, alcoholism, BM failure)