Haemoglobinopathy overview

Question 1

What makes up haemoglobin?

Answer 1

2 alpha chains
2 beta chains
One haem

Question 2

Name 3 types of haemoglobon?

Answer 2

HbA
HbA2
HbF

Question 3

What makes up HbA2?

Answer 3

2 alpha and 2 delta

Question 4

What makes up HbF?

Answer 4

2 alpha and 2 gamma

Question 5

Where are the alpha genes found?

Answer 5

Chromosome 16

Question 6

Where are the beta genes found?

Answer 6

Chromosome 11

Question 7

What are thalassaemias?

Answer 7

hereditary disorders of globin chain synthesis

Question 8

What is inadequate Hb production?

Answer 8

Microcytic hypochromic anaemia

Question 9

What is unbalanced accumulation of globin chains?

Answer 9

Ineffective erythropoiesis and haemolysis

Question 10

What is Hb Barts hydrops fetalis?

Answer 10

No functional alpha genes

Question 11

What is wrong with HbH?

Answer 11

Can’t carry oxygen

Question 12

What can be seen in HbH disease when stained?

Answer 12

HbH bodies

Question 13

How can HbH cause splenomegaly?

Answer 13

Extramedullary haematopoiesis

Question 14

How can HbH cause jaundice?

Answer 14

Haemolysis

Ineffective erythropoiesis

Question 15

What else can occur in HbH?

Answer 15

Growth retardation
Gallstones
Iron overload

Question 16

What are clinical features of Hb Barts hydrops fetalis?

Answer 16

Severe anaemia
Cardiac failure, oedema
Growth retardation
Severe hepatosplenomegaly
Skeletal and cardiovascular abnormalities

Most die in utero

Question 17

In terms of beta thalassaemia, what are the classifications?

Answer 17

Trait - asyptomatic or mild anaemia, low MCV/MCH
Intermedia - moderate needing occasional transfusion
major - severe, lifelong transfusion dependency

Question 18

What are lab features of beta thalassaemia?

Answer 18

Severe anaemia
reticulocytosis, very low MCV/MCH
Microcytosis, hypochromia, anisopoikilocytosis and target cells

Question 19

What spinal conditional can occur due to extramedullary haematopoiesis?

Answer 19

Cord compression

Question 20

What are endocrine consequences of iron overload?

Answer 20

Impaired growth and pubertal development
Diabetes
Osteoporosis

Question 21

What are cardiac consequences of iron overload?

Answer 21

Cardiomyopathy

Arrhythmias

Question 22

What are liver consequences of iron overload?

Answer 22

Cirrhosis

Hepatocellular cancer

Question 23

Give an example of a drug that causes iron chelating?

Answer 23

Desferrioxamine

Question 24

What do chelators do?

Answer 24

Bind to iron and the complexes formed are excreted in urine/stool

Question 25

Which codon in the beta globin gene substitutes glutamine to valine produsing Bs?

Answer 25

codon 6

Question 26

What is sickle crisis?

Answer 26

Episodes of tissue infarction due to vascular occlusion

Question 27

What is chronic haemolysis?

Answer 27

Shortened RBC lifespan

Question 28

What is hyposplenism?

Answer 28

Due to repeated splenic features

Question 29

What are precipitants of sickle crisis?

Answer 29

``` Hypoxia Dehydration Infection Cold exposure Stress/fatigue ```

Question 30

What are treatments of sickle crisis?

Answer 30

``` Opiate analgesia Hydration Rest Oxygen ABx ```

Question 31

What are the long term effects of sickle crisis?

Answer 31

``` Impaired growth Risk of sepsis Pulmonary hypertension Renal disease Avascular necrosis Leg ulcers Stroke ```

Question 32

What are the treatments for hyposplenism?

Answer 32

Prophylactic penicillin | Vaccine - pneumococcus, meningococcus, haemophilus

Question 33

What treatment can increase RBC turnover and increase demand?

Answer 33

Folic acid

Question 34

What can reduce severity of sickle cell disease by inducing HbF production?

Answer 34

Hydroxycarbamide