Anemias

Question 1

What is anemia?

Answer 1

A blood disorder where there is a deficiency of erythrocytes or hemoglobin.

Question 2

What are the three basic problems causing anemia?

Answer 2

1) defective erythropoiesis (defective production)
2) excessive hemolysis (premature or abnormal destruction)
3) excessive loss (ex. hemorrhage)

Question 3

What is the pathophysiology or anemia?

Answer 3

• abnormal RBC number, structure or function
• leads to decreased oxygen carrying capacity
• leads to hypoxia

Question 4

What are the manifestations of moderate anemia?

Answer 4

• dyspnea
• palpitations
• chronic fatigue

Question 5

What are the manifestations of severe anemia?

Answer 5

• chronic exhaustion
• palpitations
• profound weakness
• dizziness
• headache
• sensitivity to cold (metabolism makes heat)

Question 6

How many erythrocytes do we make in a minute?

Answer 6

180 million

Question 7

Do RBCs transport nutrients?

Answer 7

no, they transport oxygen

Question 8

What are the components of hemoglobin?

Answer 8

• globin (protein)
• heme (x4)
• iron (x4)

Question 9

What are the different types of anemia?

Answer 9

• iron deficiency
• vitamin B12 and folic acid deficiency
• pernicious anemia
• aplastic anemia
• hemolytic anemia
• hemorrhagic anemia
• sickle cell anemia

Question 10

Where does oxygen bind to hemoglobin?

Answer 10

It binds to the iron.

Question 11

What causes iron deficiency anemia?

Answer 11

inadequate intake of iron or excessive loss of iron, the type of anemia is prevalent in 3rd world countries where there is a lack of meat in the diet

Question 12

How do you treat iron deficiency anemia?

Answer 12

• treat the underlying cause

- give iron PO for 4-6 months

Question 13

Why isn’t a CBC the test of choice to detect iron deficiency anemia?

Answer 13

because it tells you about the cells and not their iron content

Question 14

What role do vitamin B12 and folic acid have in hematopoeisis?

Answer 14

They are required for DNA synthesis and cell division. If there is a deficiency there will be abnormal production of erythrocytes, leukocytes and thrombocytes.

Question 15

How are vitamin B12 and folic acid deficiency treated?

Answer 15

• give vitamin B12 (250 micrograms)

- give folic acid

Question 16

What is pernicious anemia?

Answer 16

When the gastric mucosa is damaged and doesn’t produce intrinsic factor and consequently cannot absorb vitamin B12. This impairs RBC production.

Question 17

How is pernicious anemia treated?

Answer 17

• give a high dose of vitamin B12 PO (1000 micrograms) to ensure passive absorption (no intrinsic factor needed)
• give vitamin B12 IM if there are neurological symptoms

Question 18

What is aplastic anemia?

Answer 18

Anemia due to a problem in the bone marrow. This affects RBCs, WBCs and thrombocytes.

Question 19

What causes aplastic anemia?

Answer 19

1/3 is from autoimmunity, radiation, toxic chemicals, 2/3 is idiopathic

Question 20

How is aplastic anemia treated?

Answer 20

• treat the underlying cause
• may need a transfusion
• if severe, may need a marrow transplant

Question 21

What is hemolytic anemia?

Answer 21

When there is premature or excessive hemolysis.

Question 22

What causes hemolytic anemia?

Answer 22

It can be acquired (autoimmunity or from drugs) or genetic (thalassemia).

Question 23

What is thalassemia?

Answer 23

A group of diseases where there is defective synthesis of hemoglobin. It causes the production of abnormal RBCs and the abnormal cells are destroyed.

Question 24

What are the manifestations of hemolytic anemia (in addition to hypoxia)?

Answer 24

• jaundice (from increase in bilirubin)
• splenomegaly (from increased workload)
• hepatomegaly (from increased workload)

Question 25

How is hemolytic anemia treated?

Answer 25

- treat the underlying cause - give oxygen for the hypoxia - give a transfusion - steroids to dampen hemolysis - monitor kidney function (excessive hemolysis can cause precipitation to accumulate in renal tubule and lead to renal failure) - if problem lies in spleen, splenectomy

Question 26

What is hemorrhagic anemia?

Answer 26

Anemia due to rapid or gradual loss of blood (lose both RBCs and Hb).

Question 27

What can cause hemorrhagic anemia?

Answer 27

- prolonged or heavy menses - bleeding peptic ulcers (ulcers in stomach and duodenum) - CA lesions in gastrointestinal tract - hemorrhoids

Question 28

How is hemorrhagic anemia treated?

Answer 28

- find and eliminate the cause (can be tricky)

Question 29

What causes sickle cell anemia?

Answer 29

It is a genetic problem. It is a recessive homozygous trait. If an individual is heterozygous, they are a carrier and may have mild anemia or not be affected.

Question 30

What is the pathophysiology of sickle cell anemia?

Answer 30

- mutated gene codes for Hb S instead of Hb A (adult hemoglobin) [difference is only 1 amino acid] - Hb S crystalizes on dissociation (after offloading its oxygen) at low partial pressure of oxygen (in tissues, for example) - this causes RBCs to deform and sickle - leads to chronic hemolysis - leads to vessel occlusion in the capillaries - leads to ischemia and infarction - obstructed capillaries lead to hypoxia and cause more sickling - blood viscosity is also increased, which impairs circulation... causes further hypoxia and more sickling

Question 31

What are the manifestations of sickle cell anemia?

Answer 31

- anemia - pain from ischemia (from thrombosis and infarction) - jaundice from increased bilirubin (d/t hemolysis)

Question 32

How is sickle cell anemia treated?

Answer 32

- supportive (analgesics, rest, oxygen, IV fluids and lytes) - hypertransfusion in those with increased risk (pregnant, sx) = transfusion till blood is 75% donor blood - hydroxyurea - causes production of fetal hemoglobin which has a higher affinity for oxygen but this drug also has serious SE (risk for leukemia, hepatotoxic) - marrow/stem cell transplant