Pathophysiology of Common Anemias

Question 1

Define Anemia

Answer 1

Reduction in the oxygen transport capacity of the blood
Reduction below normal in the volume of packed red cells measured by the hematocrit or reduction in the hemoglobin concentration of the blood

Question 2

Macrocytic anemia

Answer 2

Abnormally large RBC

Seen in B12 and folate deficiency

Question 3

Microcytic anemia

Answer 3

Abnormally small RBC

Seen in iron deficiency

Question 4

Normocytic anemia

Answer 4

Normal sized RBC but the RBC and Hemoglobin levels are decreased
Seen in acute blood loss, hemolysis or chronic disease

Question 5

Normochromic anemia

Answer 5

color appears normal

Question 6

Hypochromic anemia

Answer 6

color appears pale

Question 7

Increased RBC destruction =

Answer 7

hemolytic anemia

Usually in G6PD deficiency

Question 8

Impaired RBC production

Answer 8

Proliferation and maturation: B12 and folate

Hgb: iron

Question 9

Intrinsic abnormalities within Hemolytic Anemia

Answer 9

RBC membrane defects: Spherocytosis
RBC enzyme deficiency: G6PD
Hgb synthesis deficiency: thalassaemia
Abnormal Hgb structure: sickle cell anemia

Question 10

Extrinsic abnormalities within Hemolytic Anemia

Answer 10

Antibody mediated: transfussion or autoimmune
Infection: malaria or mycoplasma
Chemical: Lead poisoning

Question 11

Extravascular Hemolysis

Answer 11

Premature destruction of RBC
NO hemoglobinemia or hemogloinuria
Jaundice
Reduced haptoglobin
Hypertrophy of mononuclear phagocytes (spleen enlargement)

Question 12

Intravascular hemolysis

Answer 12

Lyses of RBC within vascular compartment
Mechanical injury, autoimmune, exogenous toxin (malaria)
Hemoglobinemia, hemoglobinuria
Jaundice
Methemoglobinuria (oxidized Hgb)
Hemosiderinuria

Question 13

Immune Mediated Hemolytic Anemia

Answer 13

Production of Anti-RBC (autoimmune or drug induced) antibodies

Question 14

Hereditary spherocytosis is

Answer 14

Anemia due to RBC membrane disorder
Autosomal dominant disease
Spherical shape (not enough spectrin), less deformable and vulnerable

Question 15

Spectrin function

Answer 15

Anchored to surface via Ankyrin and Protein 4.1 and leads to maintenance of normal shape, strength and flexibility

Question 16

Features of spherocytosis

Answer 16

Usually asymptomatic because the body can compensate but when outpaced –> chronic hemolytic anemia
Will see splenomegaly and jaundice
Treatment is a splenectomy

Question 17

G6PD deficiency

Answer 17

Leads to anemia due to inability to neutralize oxidative stress bc not enough NADPH produced to reduce GSSG to glutathione which converts H2O2 to H2O and the H2O2 accumulates –> anemia

Question 18

How H2O2 cause RBC lysis

Answer 18

Oxidation of a group on the globin chain leading to denaturation of Hgb and formation of precipitates (Heinz bodies) which cause extravascular hemolysis
When macrophages get rid of Heinz bodies, you will see RBC with bites out of them

Question 19

Causes of oxidative stress

Answer 19

Drugs, infxns, fava beans

Question 20

Direct Coombs test

Answer 20

detects antibodies bound to RBC

Question 21

Indirect Coombs test

Answer 21

Detects antibodies present in the serum