Sickle cell disease

Question 1

Cause

Answer 1

Point mutation

• glutamic acid –> valine
• A swapped with T

Question 2

Types of sickle cell disease

Answer 2

AA = normal haemoglobin
AS = sickle cell trait, heterozygous, carrier
SS = sickle cell disease, homozygous

Question 3

Action of sickle cells in blood vessels

Answer 3

Block blood flow flow because they are sticky and a different shape
-different shape because abnormal haemoglobin forms strands

Question 4

Inheritance pattern

Answer 4

Autosomal recessive

Question 5

Vaso-occlusive crisis

Answer 5

Very painful
Due to hypoxia
Affects tissues with sluggish blood flow eg bone, spleen, penis
Precipitated by cold, infection, hypoxia, stress etc
Treatment is with analgesia (often opiate), keeping warm, intravenous fluids, folic acid and if infection suspected, antibiotics
Exchange transfusion in sickle chest syndrome, severe unresponsive crisis, priapism

Question 6

Other complications

Answer 6

Brain: Stroke
Eye: Proliferative retinopathy, retinal artery occlusion, retinal detachment
Spleen: autosplenectomy
Liver: Gallstones
Urinary: Priapism, renal papillary necrosis
Locomotor: Avascular necrosis of the hip
Skin: Leg ulcers
Psychosocial: Depression

Question 7

Chronic sickle cell disease management

Answer 7

Blood transfusion in childhood to reduce the risk of stroke
Folic acid as increased requirements due to haemolysis
Antibiotics and vaccination due to hyposplenism
Hydroxycarbamide (hydroxyurea) to increase haemoglobin F
Exchange transfusion especially before surgery
Allogeneic bone marrow transplantation

Question 8

Reed Sternberg cell

Answer 8

Classical cell of Hodgkin lymphoma

Question 9

Bleomycin side effect

Answer 9

Pulmonary fibrosis

Question 10

Vincristine side effect

Answer 10

Peripheral neuropathy

Question 11

Cyclophosphamide side effect

Answer 11

Haemorrhagic cystitis