Red Cell Disorders 2

Question 1

What type of hemolysis is seen in thalassemia? What is the cause of this in β thalassemia?

Answer 1

Extravascular hemolysis; this is caused by the excess of unimpaired chains so in β thalassemia it would be do the the excess of α chains that precipitate

Question 2

α thalassemia will ↑/ ↓ sickling

Answer 2

↓ because thalassemia is a ↓ in the Hb concentration

Question 3

What is the presentation of the RBC’s in someone with thalassemias?

Answer 3

• microcytic hypochromic RBC’s

Question 4

HbS molecules have a tendency to aggregate and polymerize when ______

Answer 4

Deoxygenated; so occurs when they drop off oxygen in the tissues

Question 5

β thalassemia major is characterized by the absence of ____

Answer 5

Normal β globin gene

β0/ β0, β+/β0, β+/ β+

Question 6

Leg ulcers in sickle cell patients most common occur in the _______

Answer 6

Medial or lateral malleolus

Question 7

in β0 thalassemia, there is NO β chains produced due to nations in ______

Answer 7

Splicing or chain termination

Question 8

In sickle cell, the bone marrow becomes _______ leading to ______

Answer 8

Hyperplastic bone marrow —> changes in bony skull

Question 9

Autosplenectomy in patients with ________ can make patients prone to infections by ______________

Answer 9

HbS; capsulated infections from H. Influenza and S. Pneumonia

Question 10

What are the different types of crises seen in sickle cell?

Answer 10

• vaso-occulsive crisis
• sequestration crisis
• aplastic crisis
• hemolytic crisis

Question 11

β+ thalassemia is reduced β chain synthesis due to mutation in what region?

Answer 11

Promoter region

Question 12

describe the mutation that results in sickle cell anemia

Answer 12

• point mutation at position 6 in the β globin chain: glutamic acid → valine

Question 13

Describe the manifestation of sequestration crises in sickle cell

Answer 13

Massive entrapment of sickle RBC’s in the spleen —> splenomegaly, and hypovolemia/shock

Question 14

What can you expect to see on a histopathological slide of the spleen in someone with sickle cell?

Answer 14

They sinusoids will be congested with RBC’s with pale areas with fibrosis.
If fibrosis continues can lead to autosplenectomy

Question 15

The extravascular hemolysis in thalassemia syndromes is due to _______

Answer 15

The excess of unimpaired normal chains will aggregate causing insoluble inclusions

Question 16

Sickle crises can be precipitated by: (5)

Answer 16

• exposure to cold
• hypoxia
• infections
• dehydration
• acidosis

Question 17

Cardiac failure in β thalassemia is due to __________

Answer 17

• high output failure (severe anemia)

- iron overload (cardiomyopathy)

Question 18

Vaso-occulsive crisis in sickle cell most commonly affects the _____________ leading to _____

Answer 18

Bone; hand foot syndrome aka dactylitis which is due to blocked blood circulation

Question 19

hemoglobin defects can be classified into :

Answer 19

• hemoglobinopathies aka production of defective Hb: sickle cell, Hb C disease
• thalassemia syndromes aka decreased synthesis of globin chains of HbA

Question 20

Infection by parvovirus B19 is involved in _________ crisis in sickle cell patients

Answer 20

Aplastic

Question 21

In addition to an enlarged spleen and liver, what are some other manifestations of thalassemias?

Answer 21

• ineffective erythropoiesis —> explosion of hematopoietic marrow leading to prime time facial bones and erosion of barony cortex and new bone formation
• iron overload due (hemosiderosis or secondary hemochromatosis) to excessive dietary iron absorption and regular blood transfusions

Question 22

Mixing of a sickle cell patient’s blood with _____ is used as a screening test for sickle cell disease

Answer 22

Metabisulfite which is an oxygen consuming agent that induces sickling

Question 23

In aplastic crisis, there is a transient cessation of ______ due to _______

Answer 23

Erythropoiesis leading to worsening of anemia due to red cell progenitors being infected by parvovirus B19

Question 24

Sickle cell disease can increase the risk for an individual developing what type of renal carcinoma?

Answer 24

• renal medullary carcinoma

Question 25

what are some factors that induce sickling in sickle cell disease?

Answer 25

• presence of HbC
• dehydration
• ↓ pH
• exposure to low O2 tension