Hema. Mod.A Lec5

Question 1

splenomegaly can be due to (2)

Answer 1

extramedullary hematopoiesis

and extravascular hemolysis

Question 2

splenomegaly is not found in which type of anemia ?

Answer 2

iron deficiency anemia

Question 3

characteristics of thalassemia

Answer 3

1- high reticulocyte due to ineffective erythropoiesis

2-normoblast in peripheral blood
3-target cells
4-microcytes

Question 4

difference between thalassemia and sickle cell anemia according to erythropoiesis

Answer 4

thalassemia leads to ineffective erythropoiesis while sickle cell anemia doesn’t lead to ineffective erythropoiesis

Question 5

inheritance in sickle cell anemia and thalassemia

Answer 5

both mother and father must be carriers

Question 6

Hb abnormalities result from (3)

Answer 6

1-synthesis of abnormal Hb (leads to sickle cell anemia)

2-reduced rate of synthesis of a and b globin chains (lead to a and b thalassemia)

3-if the mother is a carrier of sickle and father is carrier of thalassemia then it leads to sickle thalassemia

Question 7

clinical classification of thalassemia (3)

Answer 7

major:
depends on blood transfusion

intermedia:
doesn’t depend on blood transfusion but has all features of thal.major (blood transfusion every once in a while)

trait/minor:
asymptomatic, carries the affected genes, no blood transfusion

Question 8

genetic classification of thalassemia: (2)

Answer 8

alpha thalassemia

beta thalassemia

Question 9

alpha thalassemia

Answer 9

the affected genes are alpha genes

-there are 4 alpha genes, 2 from mom and 2 from dad

alpha note means all alpha genes are lost

alpha+ means 3 genes are lost

cause of alpha thalassemia: deletion of genes

Question 10

types of alpha thalassemia

Answer 10

1-alpha thal.major:

HYDROPS FETALIS: intrauterine fetal death
due to deletion of all 4 genes of alpha chain

2-alpha thal.intermedia:

HbH disease: due to deletion of 3 alpha genes

3-alpha thal.trait/minor:
carrier, asymptomatic
may have 2 genes normal and 2 abnormal
or (3 genes abnormal and 1 normal ?????????)

Question 11

beta thalassemia

Answer 11

affected genes are B-genes

genes of B-chain are 2 genes, 1 from mom and 1 from dad

Question 12

types of beta thalassemia:

Answer 12

1- B note thalassemia (major):

all genes are lost

2-B+ thalassemia (minor):

small amount of gene is present

cause: due to POINT MUTATION of genes which lead to change in a.a of globin

Question 13

pathogenesis of B-Thal.Major:

Answer 13

In B-Thal there are no B genes (or reduced) so alpha chain increases and precipitates in precursors of early RBC’s which cause them to DESTRUCT IN BM (ineffective erthropoiesis)

destruction of RBC’s lead to increase in LDH and Bilirubin

BM becomes unable to synthesize more RBC’s so synthesis occurs in liver and spleen (EXTRAMEDULLARY HEMATOPOIESIS) which lead to HEPATOSPLENOMEGALY

Hypoxia occurs, stimulates the kidney to secrete EPO which stimulates production of abnormal cells

Also lead to thinning of bone (becomes friable)

Question 14

On examination by X-Ray bone appears as (in b thal.major)

Answer 14

Hair on end appearance

Question 15

in b thal.major, prominence of bone is due to

Answer 15

over expansion of BM

Question 16

in b thal.major iron overload is due to

Answer 16

increased blood transfusion , because they have more iron absorption from intestine due to low hepcidin

Question 17

pathogenesis of alpha thalassemia:

Answer 17

same as b thalassemia

Question 18

complication of b thal.major

Answer 18

1-iron overload increase deposition of iron lead to damage

2-infections: after splenectomy , infections increase because spleen has macrophage and with no spleen macrophages are low and this leads to many infections like: Meningococcal, HBV, HCV, Hemophilus, HIV, pneumococcus, yersinia(diarrhea).

so he should be vaccinated after splenectomy

Question 19

diagnosis of alpha thalassemia:

Answer 19

in case of Hb-H disease:

1-CBC shows microcytic hypochromic

2-Reticulocyte preparation:

Reticulocyte has RNA and blue spots called Hb-Bart’s granules appear

Hb-Barts granules are precipitated B chains

3-Hb electrophoresis:

Hb-H band appear

Question 20

Diagnosis of B-Thala.major

Answer 20

by electrophoresis:
HbA absent or 10%

HbF present

HbA2 little amount

Question 21

Diagnosis of B-thala.minor (carrier/trait)

Answer 21

HbA present

HbF not present or small amount

HbA2 high (>3.5)

mild hypochromic microcytic

red cell count (>5.5)

Question 22

Diagnosis of Alpha-Thala.Trait (minor)

Answer 22

by DNA analysis

Question 23

Types of sickle beta thalassemia

Answer 23

sickle cell b0 thala

sickle cell b+ thala

Question 24

sickle beta thalassemia

Answer 24

both mother and father must be carriers

MCV and MCH lower than sickle cell disease

CLINICAL PICTURE

same as sickle cell disease + splenomegaly

HB electrophoresis:

in Sickle B0

HbF present

HbS present

HbA absent

In Sickle B+
HbF present
HbS present
HbA few

CBC shows microcytic hypochromic

Question 25

Treatment of B thalassemia major

Answer 25

• Regular blood transfusion
• Iron chelation therapy
• Regular folic acid
• Splenectomy
• Endocrine therapy
• Immunization against hepatits B
• Allogenic stem cell transplantation (BM transplant) most effective