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Flashcards in Microcytic anemias Deck (51)
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1
Q

Causes of iron deficient anemia

A

iron loss

decreased iron intake

decreased iron absorption

increased iron demand

2
Q

what is hepcidin

A

prevents iron absorption

3
Q

what is transferrin

A

iron-binding glycoprotein that transports ferric iron to erythroid precursor cells in bone marrow for hemoglobin synthesis

contributes to hepatocyte iron

4
Q

what is ceruloplasmin

A

oxidizes ferrous iron to ferric iron

5
Q

what is ferroportin

A

transport protein atop epithelial cells to allow iron in from the blood

6
Q

what is TBIC

A

measure of transferrin in blood inverse of ferritin level

7
Q

what is ferritin

A

iron storage molecule

8
Q

where is ferritin highest in liver

A

parenchymal cells

9
Q

where else is ferritin found

A

bone

skeletal muscle

spleen

10
Q

where is ferritin derived from in extrahepatic sites

A

degraded RBC’s in macrophages

11
Q

what is hemosiderin

A

iron storage molecule

12
Q

what is normal percent iron saturation

A

~33%

13
Q

what will you expect to see in iron deficiency anemia

A

microcytic, hypochromic anemia

low hepcidin

low ferritin

low % saturation

low Hb and Hct

increased RDW

increased TBIC

increased free erythrocyte protoporphyrin (FEP)

14
Q

components of hemoglobin

A

heme

iron

protoporphyrin globin chains

15
Q

manifestation of iron deficiency anemia

A

Plummer Vinson Syndrome

esophageal web

atrophic glossitis

Dysphagia

beefy red tongue

16
Q

causes of sideroblastic anemia

A

x linked ALA-synthase defect

B6 deficiency

lead poisoning

drugs (chloramphenicol, isoniazid, linezolid)

copper deficiency

myelodysplastic syndrome

malignancies

17
Q

histologic manifestations of sideroblastic anemia

A

ringed sideroblasts

basophilic stippling

18
Q

what causes basophilic stippling

A

impaired RBC division

19
Q

sideroblastic anemia manifestations

A

porphyrias

20
Q

sideroblastic anemia labs

A

microcytic anemia

increased ferritin

increased iron

increased transferrin saturation

basophilic stippling

ringed sideroblasts

21
Q

why is anemia of chronic disease a microcytic anemia

A

IL-6 promotes inflammation, which increases acute phase reactants (hepcidin)

increased hepcidin decreases iron absorption, which decreases available iron

decreased EPO synthesis leads to decreased RBC synthesis

22
Q

what could cause impaired RBC production

A

chronic microbial infections

chronic immune disorders

neoplasms

23
Q

anemia of chronic disease labs

A

Early:

normocytic anemia

Late:

microcytic anemia low iron low TBIC high ferritin low reticulocytes

24
Q

what are thalassemias

A

disorders caused by inherited mutations that decrease the synthesis of globin chains, causing ineffective erythropoiesis

25
Q

what chromosome is beta subunit located

A

chromosome 11

26
Q

what chromosome is the alpha subunit located

A

chromosome 16

27
Q

what is the problem in beta thalassemias

A

defective HbA synthesis leads to under Hb hypochromic RBCs with decreased capacity to carry oxygen

28
Q

how does beta thalassemia minor usually present

A

asymptomatic

29
Q

beta thalassemia minor labs

A

increased HbA

increased HbA2 and HbF

microcytic hypochromic RBCs

30
Q

what happens in beta thalassemia major

A
  1. unpaired alpha chains precipitate and damage RBC membranes
  2. leading to ineffective erythropoiesis
  3. ultimately extravascular hemolysis in the spleen
  4. massive erythroid hyperplasia
  5. ultimately expanded hematopoiesis
31
Q

how does beta thalassemia major present

A

crewcut appearance

chipmunk facies

splenomegaly

HbA2

HbF

little to no HbA

microcytic hypochromic RBCs

target cells

32
Q

what is a risk of beta thalassemia major

A

aplastic crisis with ParvoB19

33
Q

which alpha thalassemia is asymptomatic

A

1 gene deletion

34
Q

what happens when 2 alpha genes are deleted on chromosome 16

A

mild anemia with increased RBCs

35
Q

what is a transdeletion and who does it occur most in

A

deletions in 2 chromosomes

African (Americans)

36
Q

What is a cis deletion and who does it occur most in

A

deletions on the same chromosome

Asians

37
Q

which deletion of alpha thalassemia is most severe and why

A

cis deletion is more dangerous because it is on the same chromosome, posing increased risk of transmitted severity to their progeny

38
Q

what happens when 3 alpha genes are deleted on chromosome 16

A

severe anemia

beta chains form tetramers

39
Q

what are tetramer beta globin chains called

A

HbH

40
Q

what happens when 4 alpha genes are deleted on chromosome 16

A

hydrops fetalis

gamma chains form tetramers

41
Q

what are tetramer gamma globin chains called

A

Hb Barts

42
Q

which forms of Hb damage RBCs

A

HbH

Hb Barts

43
Q

composition if HbA

A

2 alpha and 2 beta chains

44
Q

composition of HbA2

A

2 alpha and 2 Delta chains

45
Q

composition of HbF

A

2 alpha and 2 gamma chains

46
Q

composition of Hb Barts

A

4 gamma chains

47
Q

composition of HbH

A

4 beta chains

48
Q

Labs for Iron deficient Anemia

  • Iron level
  • Ferritin
  • TIBC
  • RDW
A

also microcytic hypochromic RBCs

normal- low reticulocyte count

increased serum transferrin

anisocytosis- appearance of RBCs of different sizes

49
Q

Labs for Anemia of Chronic Disease

  • Iron level
  • Ferritin
  • TIBC
  • RDW
A

increased hepcidin

50
Q

Labs for Sideroblastic Anemia

  • Iron level

Ferritin

TIBC

RDW

A

Ringed Sideroblasts

Basophilic stippling

51
Q

Labs for Thalassemias

Iron level

Ferritin

TIBC

RDW

A

Target cells

teardrop cells

reactive hyperplasia in bone marrow

crew cut appearance

chipmunk facies