RBCs: 5.5: Normocytic w/ Extravascular Hemolysis

Question 1

What is hereditary spherocytosis?

Answer 1

an inherited defect of RBC cytoskeleton membrane tethering proteins (ankyrin, spectrin, or band 3.1)

Question 2

A large range in RBC size will be indicated in what test?

Answer 2

increased RDW

Question 3

What is the problem with spherocytes?

Answer 3

they’re less able to maneuver thru the spleen- they are then consumed by splenic macs –> anemia

Question 4

Why does MCHC increase in hereditary spherocytosis?

Answer 4

bc the cell shrinks, which increases hemoglobin concentration

Question 5

What are the physical s/s of hereditary spherocytosis?

Answer 5

splenomegaly (hypertrophy), jaundice, increased unconjugated bilirubin, and bilirubin gallstones

Question 6

Increased unconjugated bilirubin –> ?

Answer 6

jaundice

Question 7

Pts with hereditary spherocytosis have an increased risk of _____ with parvovirus B19 infection of erythroid precursors.

Answer 7

aplastic crisis

Question 8

What medication increases HbF?

Answer 8

hydroxyurea

Question 9

What causes sickle cell anemia?

Answer 9

an auto recessive mutation in the beta-chain of Hb (glu is replaced with val)

Question 10

How is hereditary spherocytosis diagnosed?

Answer 10

on osmotic fragility test, the spherocytes will swell and burst in hypotonic solution

Question 11

What is the tx for hereditary spherocytosis?

Answer 11

splenectomy (anemia resolves but spherocytes persist- that’s ok- and Howell-Jolly bodies will emerge)

Question 12

What are Howell-Jolly bodies?

Answer 12

fragments of DNA left inside RBCs (look like a blue dot)

Question 13

Pts with hereditary spherocytosis have an increased risk of aplastic crisis with parvovirus B19 infection of ______ .

Answer 13

erythroid precursors

Question 14

What is the mutation in sickle cell anemia?

Answer 14

glu –> val

Question 15

What is the Hg pattern in sickle cell disease?

Answer 15

alpha-2- beta2S (2 abnormal beta genes –> 90% HbS)

Question 16

What is the problem with HbS?

Answer 16

it polymerizes when deoxygenated (hypoxemia, dehydration, acidosis) –> aggregate –> sickle shape

Question 17

Pts with hereditary spherocytosis have an increased risk of aplastic crisis with _____ infection of erythroid precursors.

Answer 17

parvovirus B19

Question 18

If RBCs lyse, what is spilled into the blood? What molecule binds to this?

Answer 18

free hemoglobin; haptoglobin

Question 19

Why are there target cells on sickle cell blood smears?

Answer 19

membrane damage to RBCs causes dehydration –> cell shrinks its cytoplasm, but Hb doesn’t decrease

Question 20

What is dactylitis?

Answer 20

swelling of the hands and feet d/t vasoocclusive infarcts of bones, esp in infants (1st presentation of sickle cell pts)

Question 21

What kind of bacteria are Sickle Cell pts susceptible to?

Answer 21

encapsulated (H. flu, Strep pneumo)

Question 22

Where do antibodies primarily come from?

Answer 22

the spleen

Question 23

Name the encapsulated bacteria.

Answer 23

"Please SHINE my SKiS"
Pseudomonas aerug.
Strep pneumo
H. influ type B
Neisseria meningiditis
E. coli
Salmonella
Klebsiella
group B strep

Question 24

What is vasoocclusive crisis in the kidney called?

Answer 24

renal papillary necrosis

Question 25

What is the hemoglobin pattern in sickle cell trait?

Answer 25

lots of alpha-2-beta-2 (HbA) and a little alpha-2-beta-2S (HbS)

Question 26

What are the s/s of sickle cell trait?

Answer 26

usually asymptomatic

Question 27

What drug causes any cell with HbS to sickle?

Answer 27

metabisulfite

Question 28

What test confirms the presence of HbS?

Answer 28

electrophoresis

Question 29

What is HbA composed of?

Answer 29

alpha-2-beta-2

Question 30

What causes hemoglobin C?

Answer 30

a mutation in the beta-chain (glu to lysine) *** hemoglobin C has ly-C-ine

Question 31

What is characteristic of HbC in a blood smear?

Answer 31

HbC crystals

Question 32

What is the inheritance of hemoglobin C?

Answer 32

auto recessive