Hematology #3 (Macrocytic Anemias, Hem A & B)

Question 1

What are sources of B12?

Explain the absorption of B12 in the body.

Answer 1

Natural sources (animal in origin): meats, eggs, dairy

B12 released by acidity in stomach and combines with intrinsic factor where it is absorbed in distal ileum

Question 2

B12 deficiency causes abnormal synthesis of ________

Answer 2

DNA

Question 3

There are two etiologies of B12 deficiency, decreased absorption and decreased intake. What is the MCC of decreased absorption?

Who should you be concerned with decreased intake in?

Answer 3

Pernicious anemia: lack of intrinsic factor due to parietal cell antibodies, leading to gastric atrophy

Vegans

Question 4

What are other causes of decreased absorption in B12 deficiency?

Answer 4

Crohn Disease
Chronic alcohol use
H2 blockers and PPIs
Metformin
Celiac Disease

Question 5

Symptoms of B12 deficiency

Answer 5

-Fatigue, exercise intolerance, pallor
-Glossitis, diarrhea, malabsorption
-Neuro symptoms***: symmetric paresthesias, lateral and posterior spinal cord degeneration (ataxia, vibratory, sensory, and proprioception deficits), decreased DTRs

Question 6

What is seen on a CBC with peripheral smear for B12 deficiency?

Answer 6

Macrocytic anemia (>100) + megaloblastic anemia (hyperhsegmented neutrophils, macor-ovalocytes)

Question 7

What other labs are shown for B12 deficiency?

Answer 7

-Decreased serum B12 levels
-Increased homocysteine (B12 breaks this down normally)

Question 8

What lab distinguishes B12 from folate deficiency?

Answer 8

Increased methylmalonic acid

-B12 converts methylmalonic acid to another enzyme normally.

Question 9

Treatment for B12 deficiency

Answer 9

-If neuro findings, B12 IM, then oral once symptoms resolve

Question 10

In patients with pernicious anemia, how often do they get IM B12 injections?

Answer 10

Lifelong, monthly injections as treatment

Question 11

What test can be done to determine the cause of pernicious anemia?

Answer 11

Schilling’s Test: Inject with B12 to determine the cause

Question 12

Folate deficiency, another macrocytic anemia, causes ____________

Answer 12

Abnormal synthesis of DNA

Question 13

Etiologies of folate deficiency

What is the MCC?

Answer 13

-MCC: Inadequate intake (alcoholics, unbalanced diet)
-Increased requirements: pregnancy, infancy, psoriasis
-Impaired absorption: Celiac, IBD, anticonvulsants, diarrhea
-Impaired metabolism: Methotrexate, Trimethoprim
-Loss: Dialysis

Question 14

Symptoms of folate deficiency

Answer 14

-Like B12, but no neuro symptoms

Question 15

What is seen on CBC with peripheral smear for folate deficiency?

Answer 15

macrocytic anemia + megaloblastic anemia (hyperhsegmented neutrophils, macro-ovalocytes)

Question 16

What other labs are shown for folate deficiency and what distinguishes it from B12 deficiency?

Answer 16

-Decreased serum folate levels
-Increased homocysteine

-Normal methylmalonic acid (this is what is different)

Question 17

Treatment for folate deficiency

Answer 17

-Folic acid supplementation

Question 18

What are some causes of macrocytic anemia?

Answer 18

-B12 Deficiency
-Folate Deficiency
-Chronic alcoholism
-Chronic Liver disease
-Hypothyroidism
-Acute Leukemia

Question 19

What does hemophilia mean?

Answer 19

Blood doesn’t clot the way it is supposed to due to lack of proteins/factors

Question 20

Hemophilia A, which is ________ deficiency, is a X-linked recessive disorder than occurs almost exclusively in males. This is the MC type of hemophilia. What are some symptoms of this?

Answer 20

Factor 8 (VIII) Deficiency –> failure of hematoma formation

-Hemarthrosis: Delayed bleeding or swelling in weight bearing joints
-Excessive hemorrhage due to trauma and surgery or incisional bleeding
-Epistaxis
-Bruising

Question 21

Regarding clotting factors, PTT (Partial Thomboplastin Time) measures ______ factors whereas PT (Prothrombin Time) measures ______ factors.

Answer 21

Intrinsic

Extrinsic

Question 22

PTT (aPTT), also known as the time___________, it prolonged in what kinds of conditions?

Answer 22

How long it takes to make a clot

Prolonged: Hemophilia A, B, Heparin, DIC, vWD

Question 23

What CBC and coagulation studies are present in Hemophilia A?

Answer 23

-Prolonged PTT
-Normal PT
-Normal Platelet Levels (bleeding time)

Question 24

What is unique about PTT in Hemophilia A and how to fix it?

Answer 24

It corrects with mixing studies

Low Factor VIII is the most sensitive test

Question 25

Treatment for Factor VIII deficiency

Answer 25

-Factor VIII infusion: can be used in response to acute bleeding or prophylaxis (pre-op, trauma, etc)

-Desmopressin (DDAVP): increases Factor VIII and vWF release from endothelial stores

Question 26

On the other hand, Hemophilia B is deficiency in what factor? It also occurs almost exclusively in males and has the same symptoms of Hemophilia A

Answer 26

Factor IX (9) Deficiency

Question 27

What CBC and coagulation studies are present in Hemophilia B?

Answer 27

Prolonged PTT
Normal PT and platelets (bleeding time)
PTT corrects with mixing studies
Factor IX is the most sensitive test

Question 28

Treatment for Hemophilia B

Answer 28

-Factor IX infusion

Question 29

What is NOT useful in Hemophilia B that is useful in Hemophilia A?

Answer 29

Desmopressin (DDAVP)