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Block 7 Week 3 > Usera: Red Blood Cell Disorders > Flashcards

Usera: Red Blood Cell Disorders Flashcards

1
Q

What stimulates the production of red blood cells in the bone marrow?

A

EPO release from interstitial cells in the peritubular capillaries of the renal cortex

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2
Q

What are 3 stimuli for EPO release from the kidney?

A

hypoxemia
anemia
left shift in O2 binding curve

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3
Q

What happens to the O2 binding curve when you:

Increase/decrease pH?
Increase/decrease DPG?
Increase/decrease temp?

A

increase pH, left shift
decrease pH, right shift

decrease DPG, left shift
increase DPG, right shift

decrease temp, left shift
increase temp, right shift

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4
Q

Ectopic production of epo leads to…

A

erythropoiesis

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5
Q

This is a sign of active erythropoiesis…

A

reticulocytes

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6
Q

So, what do reticulocytes in the blood tell you?

A

that your marrow is working fine - erythropoiesis is occuring

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7
Q

What happens to the reticulocyte count in anemia?

A

it is falsely increased - must be corrected for

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8
Q

How do you correct the reticulocyte count?

A

(Actual Hct/45) * retic count

ex: Hct = 20%, retic 15%
True retic = (20/45) * 15% = 6.6%

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9
Q

What is polychromasia? What does it imply? How do you correct for it?

A

difference in palor in RBCs; implies that reticulocytes are present; correct by dividing corrected reticulocyte count by 2

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10
Q

If your reticulocyte is greater than (blank), then your bone marrow is good to go. If your reticulocyte is less than (blank), it is ineffective.

A

3; 3

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11
Q

This is one rather obscure compensatory response to anemia

A

extramedullary hematopoiesis - your body pumps out EPO to compensate for the anemia, which increases hematopoietic stem cell division in the liver, spleen, and bone marrow - can lead to hyperplasia in the bones (ex: in the skull)

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12
Q

Extramedullary hematopoiesis is naturally present in what population?

A

babies and young children

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13
Q

Things included in a CBC?

A 
hemoglobin
Hct (how much of whole blood is RBCs)
RBC count
RBC indices
WBC count w differential
platelet count
morphology
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14
Q

In general, newborns have (blank) normal ranges than children and infants

A

higher

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15
Q

Fetal hemoglobin is HbF. What does it do to the O2 binding curve?

A

shifts it to the left

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16
Q

What happens to HbF over 6-9 months time?

A

the HbF cells are replaced by HbA and HbA2

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17
Q

WHY do children have a lower Hb than adults?

A

higher phosphorus levels in children increase the synthesis of 2,3-BPG and cause a right-shifted O2 binding curve

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18
Q

Why do men have a higher Hb than females?

A

testosterone and lack of cyclic bleeding

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19
Q

What Hb level constitutes anemia for males? Non-pregnant females? Pregnant females?

A

male: Hb < 13.5g/dL
non-preg female: Hb < 12.5g/dL
pregnant female: Hb < 11g/dL

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20
Q

Why do pregnant females have lower normal Hb ranges?

A

increased plasma volume during pregnancy causes a dilutional effect

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21
Q

What is one general difference between sickle cell anemia and thalassemias?

A

sickle cell is a qualitative defect - abnormal structure of RBC

thalassemias are quantitative defects - abnormal synthesis of Hb

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22
Q

List 6 clinical findings in anemia

A 
concentration difficulties
fatigue
dyspnea
dizziness
pallor
pulmonary flow murmur
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23
Q

How do you calculate the mean corpuscular volume and what does this measure?

A

Hct * 1000/RCB

measures the average volume of a red cell

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24
Q

What does the mean corpuscular hemoglobin content measure? What does it mean if it’s low? High?

A

the concentration of Hb within the actual RBCs (Hb/Hct); low MCHC implies that there is a defect in Hb synthesis, like in microcytic anemias; high MCHC implies spherocytosis (too much Hg packed into RBCs)

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25
Q

What does the red cell distribution width measure? When is this value useful?

A

how much the RBCs vary in size (anisocytosis); only really useful when it’s increased

*more variation, higher RDW (ex: can be seen in anemic transfusion recipients bc they have two distinct populations of cells)

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26
Q

Do mature RBCs have mitochondria? So how do they produce energy? What do they need to prevent damage by free radicals?

A

no mitochondria, no TCA, beta ox or ketone body synthesis; they use the cori cycle and anaerobic glycolysis; need glutathione synthesis from PPP

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27
Q

Soluble iron binding storage protein

A

ferritin

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28
Q

How is ferritin synthesized?

A

by macrophages in response to IL-1 and TNF-alpha

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29
Q

T/F: Serum levels of ferritin can be used to determine ferritin stores in the marrow macrophages

A

True

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30
Q

Decreased ferritin is diagnostic for (blank), while increased ferritin could be (blank)

A

iron deficiency; anemia of chronic disease or iron overload

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31
Q

The serum iron represents iron bound to (blank)

A

transferrin

32
Q

Where is transferrin synthesized?

A

in the liver

33
Q

What is normal iron level?

A

100ug/dL

34
Q

What is the total iron-binding capacity? What does it correlate with? What is a normal TIBC?

A

total iron-binding capacity is a measure of the max amount of iron the blood can carry; it correlates with the concentration of transferrin; 300ug/dL

35
Q

What is the iron saturation %? What is normal?

A

percentage of transferrin bound by iron;

serum iron/TIBC *100;

should be about 33% (means that

36
Q

So what is the difference between ferritin and transferrin?

A

ferritin is the protein that stores iron in the tissues and bone marrow (can’t escape into the serum when bound to ferritin); transferrin is the protein that carries iron in the blood

37
Q

If ferritin is high, what happens to the liver production of transferrin? What about in an iron deficient state?

A

it decreases - don’t need any more iron in the blood; it increases in iron deficiency to pump out more transferrin and get more iron circulating in the bloodstream

38
Q

4 types of microcytic anemias

A

iron deficiency
ACD
thalassemia (alpha and beta)
sideroblastic anemia

39
Q

10% of dietary iron is resorbed in the (blank); when iron is (blank), it cannot be resorbed

A

duodenum; oxidized (Fe3+)

40
Q

What two things can free elemental iron from its oxidized (ferric) form?

A

gastric acid frees it and vit C reduces ferric form of iron

41
Q

Most body iron in incorporated into (blank)

A

hemoglobin

42
Q

Most common anemia and most common nutritional deficiency worldwide

A

iron deficiency anemia

43
Q

Which populations get iron deficiency anemia?

A

toddlers (1-2yo)

females (12-49yo) due to menstruation

44
Q

What are 3 general categories of causes of iron deficiency anemia? What are some examples?

A
  1. blood loss: GI bleed, hookworm infection, NSAIDs/uclers
  2. inadequacy: prematurity, restricted diets, malabsorption
  3. Other: overutilization, pregnancy/lactation, destroyed in hemolytic anemia
45
Q

4 weird clinical findings in iron deficiency anemia?

A

esophageal web
achlohydria (low or no HCl gastric acid in stomach)
glossitis (big tongue)
koilonychia (spooned toenails)

46
Q

What happens to the following in iron deficiency anemia?

MCV?
Serum iron, iron sat?
Serum ferritin?
TIBC?
RDW?
Platelets?
A 
decreased (microcytic)
decreased
decreased
TIBC increased (increased transferrin)
RDW increased due to reticulocytes most likely
increased platelets
47
Q

Most common anemia in a hospital setting

A

anemia of chronic disease

48
Q

Anemia of chronic disease occurs with chronic (blank) due to arthritis, infection, malignancy, alcoholism, etc

A

inflammation

**production of hepcidin, which is an acute phase reactant

49
Q

What happens to the following in anemia of chronic disease?

heme synthesis?
renal secretion of EPO?
hepcidin secretion by liver?

A

decreased heme synthesis
inadequate renal secretion of EPO
hepcidin secreted by liver in response to inflammation, which prevents the release of iron to transferrin

50
Q

What does hepcidin secretion by the liver do?

A

prevents iron from getting out of marrow macs and into bloodstream to transferrin

51
Q

What happens to the following in anemia of chronic disease?

MCV?
serum iron?
TIBC?
iron sat?
serum ferritin?
A 
decreased
decreased
decreased
decreased
increased serum ferritin (due to chronic inflammation)
52
Q

Thalassemias are a (blank) abnormality of normal globin chains

A

QUANTITATIVE (not enough produced)

53
Q

In what regions are thalassemias most common?

A

Mediterranean
Africa
SE Asia

54
Q

How many copies of the beta globin gene are on each chromosome? Which chromosome? Alpha globin gene? Which chromosome?

A

one copy of beta gene on each chromosome 11 (two total loci); 2 copies of alpha gene on each chromosome 16 (4 total loci)

55
Q

What is the problem on a genomic level with beta-thalassemia?

A

defective upstream PROMOTER region of beta-globin gene (gene is OK, but promoter is defective, so no transcription)

56
Q

What happens to the following in B-thalassemia?

MCV?
Hb?
Hct?
RBC count?
RDW and ferritin?
A 
MCV: mildly decreased
Hb: decreased
Hct: decreased
RBC count: increased (trying to compensate for nonfunctional hemoglobin)
RDW/ferritin are normal

**lab values are the same for alpha-thal

57
Q

What hemoglobin types will you see an increase in in B-thalassemia?

A

HbA2 (2alpha, 2 gamma)

HbF (fetal hemoglobin)

58
Q

Should you treat a patient w beta-thalassemia?

A

No! You have the risk of iron overload

59
Q

What happens in Beta-thalassemia major on a genetic level?

A

Defects in BOTH chromosome 11’s coding for the Beta-chain, so you get ZERO HbA (2alpha2beta)

60
Q

What does Beta-thalassemia lead to?

A

severe hemolytic anemia

**not making enough of the beta chain, so body compensates by increasing RBCs – pumps out abnormal RBCs which are eaten up and hemolyzed by splenic macrophages

61
Q

What happens to RDW and reticulocytes in beta-thalassemia?

A

both are increased bc the body is trying to compensate for lack of beta globin

62
Q

What is the problem genetically in alpha thalassemias?

A

one chromosome deletion - does not cause anemia

63
Q

2 gene deletions in the alpha globin gene results in (blank)

A

alpha-thalassemia trait

64
Q

How does alpha-thalassemia differ in blacks vs Asians?

A

Blacks (α/- α/-) – mild anemia

Asians (-/- α/α) – increased risk for more serious forms **one chromosome w both alpha globin segments defective

65
Q

What is hydrops fetalis?

A

two dysfunctional chromosome 16’s; all four alpha loci are messed up - incompatible with life

66
Q

List 4 things that can lead to sideroblastic anemia

A

chronic alcoholism
Vit B6 (pyridoxine) deficiency
lead poisoning
iron overload

67
Q

What is the problem that is occuring in sideroblastic anemia?

A

defect in protoporphyrin (ultimately, heme) synthesis within mitochondria = iron cannot be incorporated into heme so iron is trapped in the mito

68
Q

What is the rate limiting step in heme synthesis? What cofactor is required?

A

Converting succinyl-CoA to aminolevulinic acid via ALAS; Vit B6 required for ALAS

69
Q

How does chronic alcoholism lead to sideroblastic anemia?

A

ETOH is a mitochonrial toxin

**30% of hospitalized alcoholics will have sideroblastic anemia

70
Q

Why does vitamin B6 (pyridoxine) deficiency cause sideroblastic anemia?

A

Vit B6 is a cofactor for the ALAS enzyme (rate-limiting step in heme synthesis)

71
Q

Vitamin B6 deficiency can be seen in alcoholics and those taking (blank) for TB

A

isoniazid

**it complexes with pyridoxine

72
Q

Most common cause of sideroblastic anemia in kiddos ages 1-5yo

A

lead poisoning

**lead-based paint, batteries, etc

73
Q

3 enzymes that are denatured in lead poisoning? What is the bottom line…like these enzymes are denatured, so what cannot proceed normally?

A

ferrochelatase: iron can’t bind w protoporphyrin

ALA dehyrase: increase in alpha-ALA

ribonuclease: ribosomes can’t break down

**you can’t incorporate iron into heme

74
Q

Clinical findings of lead poisoning?

A

Burton’s line (blue line on gums)
abdominal colic (lead deposited in enterocytes)
encephalopathy
growth retardation (lead deposits in epiphyses of long bones)
peripheral neuropathy
nephrotoxicity

75
Q

What happens to the following in lead poisoning?

Lead levels in urine?
Iron, iron sat?
Ferritin?
MCV and TIBC?

A 
elevated lead in urine **urine test is the best test
increased iron, iron sat
increased ferritin (stored)
decreased MCV
decreased TIBC (too much ferritin)
76
Q

What will you find in the bone marrow of lead poisoning patients?

A

ringed-sideroblasts (pink cells with blue dots clustered around the perimeter)

Block 7 Week 3 (5 decks)

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