Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Haematology > Haemoglobinopathies > Flashcards

Haemoglobinopathies Flashcards

1
Q

What is the most common monogenic disorder worldwide

A

haemoglobinopathies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the structure of Hb

A

tetramer - 4 globin chains
2 alpha 2 beta
1 haem attached to each globin chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is the function of globin in Hb

A

to keep haem soluble and protect it from oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the main types of Hb and what are they made up of

A 
HbA = 2a and 2B
HbA2 = 2a and 2delta 
HbF = 2a and 2gamma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

on which chromosome are alpha like genes found

A

16

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

how many alpha genes are found on each chromosome

A

2 per chromsome

4 per cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

on which chromosome are beta like genes found

A

11

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how many beta genes are found on each chromosome

A

1 per chromosome

2 per cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

expression of globin gene changes throughout embryonic life and childhood, true or false

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

which type of globin is found in all types of Hb

A

alpha chain globins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

levels of which globins increase during the foetal period

A

alpha and gamma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what happens to globin levels at birth

A

gamma levels decrease

beta levels increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

when are adult levels of Hb reached after birth

A

6-12 months old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

define haemoglobinopathy

A

hereditary condition with impaired globin synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

how are haemoglobinopathies inherited usually

A

AR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

how are haemoglobinopathies classified

A

reduced globin synthesis - thalassaemia

abnormal globin struture - sickled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

define thalassaemia

A

reduced globin chain synthesis resulting in decreased Hb synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the abnormality in alpha thalassaemia

A

defect in alpha chain - not enough alpha globulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the abnormality in beta thalassaemia

A

defect in beta chain - not enough beta globulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what are the consequences of thalassaemia

A

microcytic hypochromic anaemia
unbalanced accumulation of globin chains
haemolysis
ineffective erythropoeisis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is ineffective erythropoeisis

A

precurosor cells die in bone marrow because they are that bad

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what types of Hb does aloha thalassaemia affect

A

all kinds because all Hb types contain alpha chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the genotype of an unaffected person in alpha thalassaemia

A

presence of all 4 normal alpha genes

aa/aa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what can alpha thalassaemia do to levels of alpha globin

A

reduced or absent levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

how is alpha thalassaemia classified

A

according to number of affected alpha genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

describe alpha thalassaemia trait genotype

A

loss of 1 or 2 alpha genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

describe HbH disease genotype

A

only 1 alpha gene is left out of 4

–/-a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

describe Hb Barts Hydrops Fetalis genotype

A

no functional alpha genes at all

–/–

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

describe the features of alpha thalassaemia trait

A

asymptomatic carrier with no treatment required

microcytic hypochromic cells with mild anaemia

30
Q

are ferritin levels high or low in alpha thalassaemia trait

A

normal - excludes iron deficiency

31
Q

describe the feature of HbH disease

A

more severe form of alpha thalassaemia

anaemia with low MCV and MCH

32
Q

what happens to excess beta chains in HbH disease

A

they form tetramers B4 called HbH

33
Q

clinical features of HbH disease

A

jaundice
splenomegaly
may need transfusion

34
Q

describe features of Hb Barts Hydrops Fetalis

A

most severe form of alpha thalassaemia

no alpha chains results in Hb Barts (gamma4) and HbH (B4)

35
Q

clinical features of Hb Barts

A 
profound anaemia 
incompatible with life 
cardiac failure 
growth retardation 
severe hepatosplenomegaly
36
Q

what is the cause of beta thalassaemia

A

point mutation resulting in reduced or absent B globulin

37
Q

which type of Hb is affected in beta thalassaemia

A

HbA as it is the only one containing beta chains

38
Q

how is beta thalassaemia classified

A

according to clinical severity

39
Q

what are the subtypes of beta thalassaemia

A

beta thalassaemia trait
beta thalassaemia intermidia
beta thalassaemi major

40
Q

what is the genotype of beta thalassaemia trait

A

B+/B or Bo/B

41
Q

what are the features of beta thalassaemia trait

A

asymptomatic
no/mild anaemia
low MCV/MCH
raised HbA2

42
Q

what is diagnostic of beta thalassaemia trait

A

raised HbA2 levels

43
Q

what is the genotype of beta thalassaemia intermedia

A

B+/B+ or Bo/B+

44
Q

what are the features of beta thalassaemia intermedia

A

moderate severity

requires occasional transfusion

45
Q

what is the genotype of beta thalassaemia major

A

Bo/Bo

46
Q

what are the feature of beta thalassaemia major

A

no beta chain synthesis
cannot make HbA
severe lifelong transfusion dependency

47
Q

when does beta thalassaemia major present

A

6-24 months old

as HbF goes down and body tries to make HbA

48
Q

consequences of beta thalassaemia major

A 
extramedullary haemoatopoeisis
hepatosplenomegaly 
skeletal defects 
organ damage 
spinal cord compression
49
Q

what is extramedullary haemoatopoeisis

A

RBC production outwith the bone marrow ie in liver and spleen leading to hepatosplenomegaly

50
Q

management of beta thalassaemia major

A

regular tranfusion programme
maintain Hb at 95-105g/L
bone marrow transplant curative

51
Q

what is a complication of lifelong blood transfusions

A

iron overload

52
Q

what are complications of iron overload

A

endocrine: DM and pancreas, osteoporosis, impairs growth
cardiac: cardiomyopathy, arrhythmias
liver: cirrhosis, HCC
sepsis: bacteria love iron

53
Q

management of iron overload in beta thalassaemia major needing lifelong transfusion

A

iron chelating drugs eg desferrioxamine

54
Q

what is the cause of sickling disorders

A

point mutation in codon 6 of beta globin chain in chromosome 11 substitutes glutamine for valine which produces Bs

55
Q

what is the structure of HbS

A

2 alpha and 2 Bs

56
Q

why is HbS bad

A

HbS polymerises if exposed to low oxygen levels for a long time which distorts the shape of the RBC and membrane

57
Q

what is the genotype of sickle cell trait

A

1 normal and 1 abnormal beta chain

B/Bs

58
Q

features of sickle cell trait

A

asymptomatic carrier state

few clinical features as HbS levels are too low to polymerise

59
Q

can cells sickle in sickle cell trait

A

may sickle in severe hypoxia eg high altitude or anaesthesia

60
Q

what is seen on the blood film of sickle cell trait

A

HbA

HbS <50%

61
Q

what is the genotype of sickle cell anaemia HbSS

A

Bs/Bs

62
Q

what proportion of HbS is present in HbSS

A

> 80%

63
Q

why are sickle cells dangerous

A

disrupt microvasculature and cause vaso-occlusion resulting in tissue ischaemia and pain

64
Q

why do you get hyposplenism in HbSS

A

due to multiple splenic infarcts

65
Q

what is a sickle crisis

A

episodes of tissue infarction dur to vascular occlusion

severe pain depending on site affected

66
Q

list precipitants of a sickle crisis

A 
hypoxia
dehydration 
stress 
cold 
infection 
or none
67
Q

what is the acute management of a sickle crisis

A 
opiate analgesia 
rehydration 
oxygen 
rest 
antibiotics if there are signs of infection

red cell exchange transfusion

68
Q

what is involved in red cell exchange transfusion

A

venesection –> transfusion –> venesection –> transfusion …

69
Q

what is the long term management of HbSS

A

hyposplenism: prophylactic penicillin and vaccinations
folic acid
hydroxycarbamide
regular transfusion in some cases to prevent stroke

70
Q

what is the role of hydroxycarbamide

A

induces HbF production to reduce disease severity

71
Q

what investigations are done to diagnose haemoglobinopathies

A 
FBC
iron studies
blood film - microcytic hypochromic cells 
ethnicity 
Hb measures: HPLC and electrophoresis
72
Q

what is HPLC

A

high performance liquid chromatography

Haematology (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions