Sicke Cell Disease

Question 1

Sickle cell disease is an autosmal __________ disease in which there is chronic hemolytic anemia and vasoocclusion

Answer 1

Recessive

Question 2

There is _________{extravascular/intravascular} hemolysis in SCD

Answer 2

Extravascular hemolysis

Question 3

Sickle cell disease is caused by a missense _________ mutation with substitution of valine for glutamic acid at the ________ position of the B globin chain

Answer 3

Point mutation

Sixth

Question 4

Heterozygous people have _______ (no/little/mild) anemia

Answer 4

No

Question 5

Homozygous condition HbSS produces a severe __________(microcytic/normocytic/macrocytic) anemia

Answer 5

Normocytic

Question 6

Sickle cells are protective against _____________

Answer 6

Plasmodium falciparum malaria

Question 7

Most life threatning complications of sickle cell diseases?

Answer 7

Acute chest syndrome
Stroke
Infection

Question 8

HbS molecules in the RBCs aggregate and polymerize into long, needle like fibers when __________ (deoxygenated/oxygenated)

Answer 8

deoxygenated

Question 9

Oxygen ________ (favours/inhibits) sickling of RBCs

Answer 9

inhibits

Question 10

HbS concentration should be more than ____% for sickling to occur

Answer 10

60%

Question 11

In sickle cell trait, HbS concentration is less than ____% so sickling doesn’t occur

Answer 11

50%

Question 12

What are the factors that increase the concentration of deoxyhemoglobin?

Answer 12

Acidosis
Volume depletion
Hypoxemia

Question 12

What are the factors that increase the concentration of deoxyhemoglobin?

Answer 12

Acidosis
Volume depletion
Hypoxemia

Question 13

Acidosis shift the O2 dissociation curve to the ______ (right/left) causing O2 release from RBCs and leading to increase in deoxyHb

Answer 13

right

Question 14

How does volume depletion causes sickling?

Answer 14

Volume depletion in which intracellular dehydration causes an increase in concentration of deoxyHb

Question 15

Initial sickling is _________ (reversible/irreversible)

Answer 15

reversible (if O2 is administered)

Question 16

_________ sickling is irreversible because of membrane damage

Answer 16

Recurrent

Question 17

How membrane damage makes sickling an irreversible thing?

Answer 17

An influx of calcium ions cross links membrane proteins, causing the eflux of K+ and water out of the cell and cell gets dehydrated

Question 18

Sickle cells undergo hemolysis in the liver, spleen so it is __________ (extrvascular/intravascular) hemolysis

Answer 18

extravascular

Question 19

How does vasoocclusion occur in SCD?

Answer 19

Sickle cells are sticky bcz of increased expression of adhesion molecules on their surface leading to ischemic injury

Question 20

What is the mechanism of hydroxyurea?

Answer 20

Hydroxyurea stimulates the synthesis of HbF, HbF has high affinity for O2 so no sickling

Question 21

Increased HbF at birth prevents sickling until ______ months of age

Answer 21

5-6 months

Question 22

What are the clinical findings in SCD?

15 findings

Answer 22

Severe anemia
Vasoocclusive crisis
Dactylitis
Acute chest syndrome
Avascular necrosis of bone
Autosplenectomy
Increased susceptibility to infections
Aplastic RBC crisis
Sequestration crisis
Calcium and bilirubinate gallstones
Acute n chronic liver disease
Stroke
Recurrent leg ulcers
Proliferative retinopathy
Endstage renal failure

Question 23

frequency of VOC is variable but may be as many as ____ or more crises a year

Answer 23

six

Question 23

frequency of VOC is variable but may be as many as ____ or more crises a year

Answer 23

six

Question 24

Dactylitis refers to painful swelling of hands and feet due to ________ in the metacarpal bones

Answer 24

infarction

Question 25

Dactylitis occurs in ________ (infants/adults/elder)

Answer 25

infants (6-9 months; rarely seen after 2 years)