Microcytic Anemia 9/27

Question 1

what can cause falsely abnormal MCV? (5)

Answer 1

• cold agglutins
• hyperglycemia
• reticulocytosis
• leukocytosis
• acute hemolysis

Question 2

Corrected Reticulocyte count

Answer 2

Absolute Reticulocyte count x (pt’s Hgb/normal Hgb)

Hypoproliferation: <2%

Question 3

To correct for shift Reticulocytes (some released early due to low Hgb ~12), calculate the Reticulocyte production index:

Answer 3

(Reticulocyte %/ Reticulocyte maturation time) x (Hgb/15)

Question 4

Reticulocyte maturation time for:
Hgb of 15?
Hgb of 12?
Hgb of 8?
Hgb of 5?

Answer 4

15: 1 day
12: 1.5 days
8: 2 days
5: 2.5 days

Question 5

What does RPI less than 2 indicate?

Answer 5

Patients bone marrow is not making enough Reticulocytes

RPI over 3 indicates the marrow is responding appropriately to anemia.

Question 6

What accounts for decreased red cell production? (Reticulocytopenia)

Answer 6

1. Hgb synthesis lesion: iron deficiency, thalassemia, anemia of chronic disease
2. DNA synthesis lesion: megaloblastic anemia
3. DNA synth inhibitor drugs
4. Hematopoetic stem cell lesion: leukemia
5. Bone marrow infiltration: lymphoma, sarcoidosis, etc

Question 7

What accounts for increased RBC destruction/loss? (Reticulocytosis)

Answer 7

1. Acute blood loss
2. Intrinsic Hemolysis: membrane lesion, Hgb lesion, glycolysis abnormality, oxidation lesion (G6PD deficiency)
3. Extrinsic hemolysis: immune, angiopathic.
4. Valve dysfunction
5. Infection
6. Hypersplenism

Question 8

Normal RDW, low MCV

Answer 8

Thalassemia

Chronic disease

Question 9

Normal RDW, high MCV

Answer 9

Aplastic anemia

Myelodysplasia

Alcohol

Question 10

Normal RDW and normal MCV

Answer 10

Chronic disease (90%)

Hereditary spherocytosis

Acute bleed

Cirrhosis

Uremia

Question 11

High RDW and low MCV

Answer 11

Iron deficiency

S-thalassemia

RBC fragmentation

Question 12

High RDW and high MCV

Answer 12

B12/folate

Autoimmune hemolysis

Cold agglutins

Question 13

High RDW and normal MCV

Answer 13

Early factor deficiency

SS disease

SC disease

Sideroblastic anemia

Myelofibrosis

Question 14

For microcytic anemia, MCV IS LOW. What do RDW values tell us?

Answer 14

High RDW: iron deficiency, S-thalassemia, RBC fragmentation

Low RDW: thalassemia, chronic disease

Question 15

What is the differential diagnosis of microcytosis (low MCV)?

Answer 15

-iron deficiency
-thalassemia
•B: elevated Hgb A2 or F
-anemia of chronic disease
-sideroblastic anemia (rare)
-lead poisoning (rare)
-zinc deficiency

Question 16

Cause of microcytosis?

Answer 16

Reduced Hgb synthesis

Either iron defects OR hemoglobinopathies

Question 17

How to test for iron deficiency? (4)

Answer 17

1. Iron
2. TIBC
3. Iron or transferrin saturation
4. Ferritin

Question 18

What molecule transports iron after absorption?

Answer 18

Transferrin

Question 19

What molecule stores iron in the liver and heart?

Answer 19

Ferritin (10-20% of absorbed iron)

Question 20

Common reasons for iron loss?

Answer 20

Ulcers
GI bleeds
Liver disease 
IBS
Hemorrhoids
Colon cancer

Question 21

How much iron is lost in females per day?

Answer 21

1-3 mg.

Pregnancy: 6 mg/day

Question 22

How can exercise result in iron deficiency?

Answer 22

1. GI tract blood loss
2. Exercise-induced hemolysis
3. Increased levels of hepcidin

Also… Bariatric surgery.

Question 23

How do you approach iron deficiency anemia?

Answer 23

In older makes, LOOK FOR GI SOURCE

how else can one lose blood? Menstruation, post surgery.

FIND BLEED; STOP BLEEDING

Question 24

What is the go-to iron therapy treatment and dosage?

Answer 24

Ferrous sulfate: 325 PO per day.

Question 25

How to treat iron deficiency If ferrous sulfate is not tolerated?

Answer 25

Ferrous gluconate Iron drops Lower dose + vitamin C/ cranberry juice

Question 26

If unresponsive to oral iron therapy, utilize parenternal iron therapy. What drugs are used? (5)

Answer 26

1. Iron dextran: start w/ 25 mg to test for adverse rxn, then give 975 mg. 2. Ferric Gluconate: 125mg/hour x 7 sessions 3. Iron sucrose 4. Ferumoxytol: 510mg over 17 seconds. Repeat in a week 5. Ferric carboxymaltose: 750mg. Repeat in one week

Question 27

What is hepcidin and where is it synthesized?

Answer 27

Synth in LIVER. prevents parenchyma iron overload Reduces quantity of circulating iron by preventing its exit from cells (erythrocytes & macrophages)

Question 28

what molecule does hepcidin work on and how?

Answer 28

Hepcidin binds to ferroportin* and induces its internalization and degradation. Keeps iron inside RBCs. *ferroportin is a transmembrane protein that transports iron from inside the cell to the outside -> bloodstream.

Question 29

What happens with low or no hepcidin?

Answer 29

Parenchymal iron overload

Question 30

Iron testing: iron/TIBC/ferritin in iron deficiency?

Answer 30

Serum iron: LOW TIBC: high ferretin: LOW

Question 31

Iron testing: iron/TIBC/ferritin in anemia of chronic disease?

Answer 31

Serum iron: LOW TIBC: LOW Ferretin: high

Question 32

When do you get Hgb electrophoresis in evaluating anemia? (3)

Answer 32

Family history of hemoglobinopathies/ race Microcytosis w no or mild anemia Iron studies not indicative of another process

Question 33

What is the cause of sideroblastic anemia?

Answer 33

Elevated iron Usually acquired disorder: MDS, alcohol, Meds Can be X-linked

Question 34

Multiple small blue/black spots on RBC indicate basophilic stippling. What does this mean?

Answer 34

Pb (LEAD) TOXICITY or thalassemia

Question 35

What are the clinical manifestations of lead poisoning?

Answer 35

Hypochromic microcytosic anemia Lead inhibits heme production by preventing iron incorporation into protoporphyrin ring Symptoms: anorexia, abdominal pain, irrationality. RADIAL PALSY