Chapter 5

Question 1

what are the lab findings for sideroblastic anemia

Answer 1

Laboratory findings include increased􏰓 ferritin, decreased TIBC, 􏰓 increased serum iron, and􏰓 increased %saturation
(iron-overloaded state)

Question 2

hemoglobin barts

Answer 2

Four alpha genes deleted –> lethal in utero (hydrops fetalis); gamma chains form tetramers (Hb Barts) that damage RBCs; Hb Barts is seen on electrophoresis.

Question 3

beta tetramers

Answer 3

Three alpha chains genes deleted –> severe anemia; chains form tetramers (HbH) that damage RBCs; HbH is seen on electrophoresis.

Question 4

splenomegaly plus iron deficiency anemia…

Answer 4

really got to think thalassemias

Question 5

hallmark of beta thal. minor…

Answer 5

increase in hemoglobin A2 (2 alpha, 2 delta)

as well as increased in fetal Hb (2 alpha, 2 gamma)

Question 6

What is seen on the slide of beta thal MAJOR….

Answer 6

lots of varying RBCs all over the slide

• especially target cells
• increase in surface area to vol ratio

-in minor, versus iron deficiency anemia, won’t be a lot of variability…

Question 7

why is there erythroid hyperplasia in beta thal??

Answer 7

because we have tons of EPO but we aren’t making a response from marrow
so we have a massive response from ALL bone marrow
even that in the face

Question 8

What results from extramedullary hematopoesis in beta thalassemia?

Answer 8

hepatosplenomegaly that make nucleated (immature RBC)

Question 9

lab findings of folate def anemia

Answer 9

Clinical and laboratory findings include
I. Macrocytic RBCs and hypersegmented neutrophils (> 5 lobes, Fig. 5.5) 2. Glossitis
3. decreased serum folate
4. increased serum homocysteine (increases risk for thrombosis)
5. Normal methylmalonic acid

Question 10

lab findings of b12 def anemia

Answer 10

Vitamin B12 is a cofactor for the conversion of methylmalonic acid to succinyl CoA (important in fatty acid metabolism).

Vitamin B12 deficiency results in increased levels of methylmalonic acid, which impairs spinal cord myelinization.

Damage results in poor proprioception and vibratory sensation (posterior column) and spastic paresis (lateral corticospinal tract).

• decreased serum vitamin B12
• increased serum homocysteine (similar to folate deficiency), which increases risk for thrombosis
• increased methyl malonic acid (unlike folate deficiency)

Question 11

what can happen to reticulocyte count in anemia????

Answer 11

it can be falsely elevated!!!

RC is corrected by multiplying reticulocyte count by Hct/45.

Corrected count > 3% indicates good marrow response and suggests peripheral destruction.

Corrected count < 3% indicates poor marrow response and suggests underproduction.

Question 12

Clinical features of extravascular hemolysis

Answer 12

Clinical and laboratory findings include:

anemia with splenomegaly, jaundice due to unconjugated bilirubin, and increased risk for bilirubin gallstones

Marrow hyperplasia with corrected reticulocyte count > 3%

Question 13

clinical features of intravascular hemolysis

Answer 13

Intravascular hemolysis involves destruction of RBCs within vessels.
1. Clinical and laboratory findings include
i. Hemoglobinemia
ii. Hemoglobinuria
iii. Hemosiderinuria- Renal tubular cells pick up some of the hemoglobin that
is filtered into the urine and break it down into iron, which accumulates as
hemosiderin; tubular cells are eventually shed resulting in hemosiderinuria. iv. Decreased serum haptoglobin

Question 14

Most common cause of death in adult sickle cell patients?

Answer 14

Acute chest syndrome-
vasa-occlusion in pulmonary microcirculation
i. Presents with chest pain, shortness of breath, and lung infiltrates
ii. Often precipitated by pneumonia
iii. Most common cause of death in adult patients

Question 15

what is the percentage of HbS in sickle cell trait?

Answer 15

Sickle cell trait is the presence of one mutated and one normal beta chain chain;
results in < 50% HbS in RBCs (HbA is slightly more efficiently produced than HbS)

Generally asymptomatic with no anemia;
RBCs with < 50% HbS do not sickle in
vivo except in the renal medulla.

Question 16

what is hemoglobin C disease?

Answer 16

Autosomal recessive mutation chain of hemoglobin.

Normal glutamic acid is replaced by lysine.

Less common than sickle cell disease.

Presents with mild anemia due to extravascular hemolysis.

Characteristic HbC crystals are seen in RBCs on blood smear.

Question 17

What is G6P deficiency?

Answer 17

X-linked recessive disorder resulting in reduced half-life of G6PD; renders cells susceptible to oxidative stress

RBCs are normally exposed to oxidative stress, in particular

Glutathione (an antioxidant) neutralizes H20 2• but becomes oxidized in the process

NADPH, a by-product of G6PD, is needed to regenerate reduced glutathione.

Decreased G6PD –> decreased NADPH –> reduced glutathione –> oxidative injury –> intravascular hemolysis

Question 18

How does drug-induced hemolytic anemia get started?

Answer 18

Drug may induce production of autoantibodies (e.g., a-methyldopa) that bind self antigens on RBCs

Drug may attach to RBC membrane (e.g., penicillin) with subsequent binding of antibody to drug-membrane complex

Associated with SLE (most common cause), CLL, and certain drugs (classically, penicillin and cephalosporins)