Haemoglobinopathies - sickle cell anaemia

Question 1

2 conditions that will be focused on?

Answer 1

Sickle cell

Thalassaemias

Question 2

What type of anaemia do sickle cell disease and thalassaemias cause?

Answer 2

Congenital causes haemolytic anaemia

Question 3

What is sickle cell, what is its mutation?

Answer 3

Mutations leading to structurally abnormal globin chain

point mutation in the beta gene

majority are autosomal recessive

glu-> valine

Question 4

Haemoglobinopathies?

Answer 4

a group of inherited blood disorders involving the haemoglobin, the protein of red blood cells.

Question 5

What rbcs are caused by sickle cell?

Answer 5

Question 6

Painful vaso-occlusive crises caused by sickle cell disease?

Answer 6

• Bone pain
• Hand- foot syndrome
  Stroke - affects children

Question 7

Effects of sickle cell anaemia? (general)

Answer 7

Chronic haemolytic anaemia

Increased infection risk

Reduced life expectancy

Vaso-occlusive crises

organ damage due to microinfarcts

reduced life expectancy

Question 8

Effects of chronic haemolytic anaemia? - sickle cell disease

Answer 8

Gallstones

Aplastic cross

• organ damage due tot microinfarcts

Question 9

Infection in relation to sickle cell disease?

Answer 9

Hyposplenism

Osteomyelitis

Question 10

Dental abnormalities and sickle cell disease?

Answer 10

Sickling in jaw mimicking dental pain

Facial swelling during crisis

Tooth pulp affected by sickling

Increased risk of infection

Delayed eruption and hypolasia of dentition

Question 11

Management of sickle cell disease?

Answer 11

General considerations
- hydration
- oxygenation
- analgesia

Life long prophylaxis against infection
- vaccination
- penicillin (and malarial prophylaxis)

Folic acid

Blood transfusion - prior to major surgery and ga
- especially pain in lungs/chest

GENE THERAPY

Allogeneic blood transfusion can cure

Question 12

Pt with sickle cell - morning or afternoon app?

Answer 12

Morning (well rested)

Question 13

Pt with sickle cell advise before dental work?

Answer 13

liase with haematology consultant in advance

Morning app

Recommend good fluid intake prior to procedure

LA preferred option

Adequate analgesia

Antibiotics to cover invasive tx

avoidance of hypoxia and hypothermia around GA
- LA

Question 14

What are the units making haemoglobin?

Answer 14

2 alpha chians

2 beta chains

Question 15

genes for the 2 alpha chains?

Answer 15

4 alpha genes

Question 16

genes for the 2 beta chains?

Answer 16

2 beta genes

Question 17

What is fetal haemoglobin gene combination?

Answer 17

alpha-gamma (aayy)

Question 18

2 main causes of haemoglobinopathies?

Answer 18

mutations leading to structurally abnormal globin chain:
- HbS(sickle cell)

reduced or absent globin chain production
- thalassaemia

Question 19

types of thalassaemia?

Answer 19

dependent on the absent/reduced globin chain

alpha a
- alpha thalassaemia

beta b

delta d

gamma y

Question 20

Inheritance of sickle cell disease?

Answer 20

majority are autosomal recessive

Question 21

What does mutated beta chain and alpha chain combining cause?

Answer 21

HbS

Question 22

Effect of HbS on RBC morphology?

Answer 22

RBC biconcave makes the RBC flexible

sickle cell, in times of stress or low oxygen concentration: haem crystallises causes RBC to become rigid ‘sickly’ shape

cant squeeze through micro-vasculature and causes vaso-occlusion

Question 23

Types of sequestration crises caused by sickle cell anaemia?

Answer 23

spleen

liver

Question 24

when is blood transfusion indicated in sickle cell?

Answer 24

before major surgery under GA