RBCs: 5.6: Normocytic w/ Intravascular Hemolysis

Question 1

What causes paroxysmal nocturnal hemoglobinuria?

Answer 1

an acquired defect of GPI, an anchoring protein for protective surface proteins against complement, on blood cells

Question 2

What destroys the cells in paroxysmal nocturnal hemoglobinuria?

Answer 2

complement

Question 3

Is the hemolysis in paroxysmal nocturnal hemoglobinuria intra- or extravascular?

Answer 3

intravascular

Question 4

Shallow breathing leads to what acid-base disturbance?

Answer 4

respiratory acidosis

Question 5

What are the lab findings of paroxysmal nocturnal hemoglobinuria?

Answer 5

hemoglobinemia
hemoglobinuria
hemosiderinuria (days later)

Question 6

How do you screen for paroxysmal nocturnal hemoglobinuria?

Answer 6

give sucrose- activate complement- positive = cell destruction

Question 7

How do you confirm paroxysmal nocturnal hemoglobinuria?

Answer 7

lack of CD55 (DAF) on RBCs or the acidified serum test

Question 8

What is the main cause of death in paroxysmal nocturnal hemoglobinuria?

Answer 8

thrombosis (platelet destruction activates coag cascade)

Question 9

What are some complications of paroxysmal nocturnal hemoglobinuria?

Answer 9

Fe deficiency anemia (lost in urine)

AML (bc already have 1 mutation in myeloid stem cells)

Question 10

How is G6PD inherited?

Answer 10

X-linked

Question 11

What does glutathione do?

Answer 11

protects RBCs against oxidative stress

Question 12

What reduces glutathione?

Answer 12

NADPH

Question 13

What produces NADPH in an RBC?

Answer 13

G6PD

Question 14

What is the underlying problem in G6PD?

Answer 14

a reduced half-life of G6PD –> increased suscept. to oxidative stress in RBCs

Question 15

What are the 2 variants of G6PD?

Answer 15

1. African (mild)

2. Mediterranean (moderate)

Question 16

How long is the G6PD half life in a normal pt?

Answer 16

as long as the RBC’s life

Question 17

Name 2 diseases that are protective for falciparum malaria.

Answer 17

1. sickle cell

2. G6PD

Question 18

Name 3 drugs that cause oxidative stress to RBCs.

Answer 18

1. primaquine
2. sulfa drugs
3. dapsone

Question 19

Oxidative stress in RBCs precipitates hemoglobin into a ____.

Answer 19

Heinz body

Question 20

How does a G6PD crisis present?

Answer 20

hemoglobinuria, back pain (nephrotoxic) within hours of exposure

Question 21

What is the screening test for G6PD?

Answer 21

a Heinz preparation (highlights precipitated Hb)

Question 22

What is the confirmatory test for G6PD?

Answer 22

enzyme studies after the acute episode has resolved

Question 23

What is immune hemolytic anemia?

Answer 23

Ab mediated (IgG or IgM) destruction of RBCs

Question 24

What kind of Ab causes immune hemolytic anemia?

Answer 24

IgG or IgM

Question 25

What happens to IgG covered RBCs in immune hemolytic anemia?

Answer 25

the spleen macs eat the membrane --> spherocytes

Question 26

Name 2 diseases associated with immune hemolytic anemia.

Answer 26

SLE, CLL

Question 27

Name 2 drugs that can cause immune hemolytic anemia.

Answer 27

1. penicillin | 2. methyldopa

Question 28

What is the tx for immune hemolytic anemia?

Answer 28

1. stop offending drug, if applicable 2. steroids 3. IVIG (distraction technique) 4. splenectomy

Question 29

At what temperature does IgM immune hemolytic anemia prefer?

Answer 29

cold temps

Question 30

Name 2 diseases that IgM immune hemolytic anemia are seen in.

Answer 30

Mycoplasma pneumo | mononucleosis

Question 31

How is immune hemolytic anemia diagnosed?

Answer 31

Coombs test (esp direct)

Question 32

How does a direct Coombs test work?

Answer 32

confirms the presence of Ab-coated RBCs (anti-IgG added- positive if another Ab already existed)

Question 33

How does a indirect Coombs test work?

Answer 33

it checks for Abs in the serum (give test RBCs to see if agglutination occurs when anti-IgG is added)

Question 34

What is microangiopathic hemolytic anemia?

Answer 34

when RBCs are destroyed as they pass thru BVs with platelet microthrombi on the sidewalls

Question 35

What cells result from microangiopathic hemolytic anemia?

Answer 35

shistocytes

Question 36

Name 5 syndromes that cause shistocytes.

Answer 36

1. DIC 2. HUS 3. TTP 4. HELLP 5. microangiopathic hemolytic anemia

Question 37

What is another name for a shistocyte?

Answer 37

helmet cell