Brainscape's Knowledge GenomeTM

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


See full index

HEMATOLOGY > HEMOGLOBINOPATHIES > Flashcards

HEMOGLOBINOPATHIES Flashcards

1
Q

What are diff. forms of Hb? How diff. are they ?

A
  • HbA (2 alpha and 2 beta chains)
  • HbA2 (2 alpha and 2 delta)
  • HbF (2 alpha and 2 gamma)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Wich is the major Hb in adults?

A
  • HbA (2 alpha and 2 beta chains)

- –only 2% of HbA2

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

What is the signifcance of globin chains?

A
  • KEEPS HAEM soluble and protect heme from oxidation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How are diff. forms of Hb formed? -

A
  • Genetic control

- alpha like genes on Chromosome 16 (2 alpha genes per CHROMOSOME)

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

How does the globin chain prodn change over the years?

WHy is this significant?

A
  • Beta Hb chain prodn RAMPS up by 6-12 months of age
  • —gamma globin chain prodn is reduced at this time
  • –Beta-thalassaemia only presents at 6-12 months
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are hemoglobinopathies?

A

hereditary conditions affecting the GLOBIN chain synthesis

—autosomal RECESSIVE d.o

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

What are the 2 main gr. of hemoglobinopathies?

A
  1. THALASSAEMIAS (DECR. rate of NORMAL globin chain synthesis)
  2. Structural Hb variants (mutation in the structural prodn of the Hb)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Give an example of structural Hb variant hemoglobinopathies?

A

-SICKLE cell anaemia

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

What is affected in Alpha thalassaemia?

A

Alpha chains are affected

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

What is a consequence of thalassaemias?

A
  1. INADEQUATE Hb prodn–> MICROCYTIC HYPOCHROMIC anaemia
  2. If severe (UNBALANCE accumulation of GLOBIN chains):
    - hemolysis > JAUNDICE
    - ineffective erythropoiesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the geographical distribution of Thalassaemia.

A
  • MALARIA endemic areas has allowed the MUTATIONs to cherish
    (central and east africa; ASIA, peri-meditarre.)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What occurs with ALPHA THALASSEMIA?

A

—–thalassaemia occurs with deletion of ONE or BOTH alpha genes from chromosome 16

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

What occurs with ONE working alpha gene out of 4?

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

If NO working genes are left? -

A

Hb Barts Hydrops Fetalis

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

When does someone have thalassaemia trait?

How does the Alpha Thalassaemia trait present as?

A

if they only ONE or 2 alpha genes missing

———MILD anaemia
(microcytic, hypochromic red cell)—-but normal Hb levels

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

How to differentiate from iron def. (thalassaemia trait) ?

A
  • FERRITIN is normal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What occurs pathophysiologically with alpha-thalassaemia?

A
  • beta chains wnats to bind to something

- —they start to STICK to each other, forming TETRAMERS (HbH)—-red cell inclusions are seen of HbH

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

What is seen with HbH disease?

A
  • ANAEMIA with v.LOW MCV and MCH
  • Jaundice
  • splenomegaly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is seen on blood film of Hb Barts Hydrops Fetalis?

A
  • no Hb

- NUMEROUS nucleated red cells

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

What is seen in Hydrops fetalis?

A 
Profound anaemia
Cardiac failure
Growth retardation
Severe hepatosplenomegaly
Skeletal and cardiovascular abnormalities
Almost all die in utero
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Who presents with Beta thalassaemia major?

A

Bbies 6-24 months of age

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

How does Beta thalassaemia Major present as?

A
  • skeletal damage
  • organ damage
  • hepatosplenomegaly
  • —-PALLOR and FAILURE to thrive

—-all as a result of extramdeullary haematopoiesis

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

How to manage Beta Thal Maj?

A
  • regular transfusion programme (supresses ineffective erythropoiesis)
  • –allows NORMAL growth and develop.
24
Q

What may occur with freq. transfusions?

How to prevent over-absorption of iron ?

A
  • IRON overload —-main cause of mortality

—-maintain Hb at 95-105g/l

25
Q

What endocrine dysfxns may result from iron overload?

A
  • DIABETES
  • HYPOTHYROIDISM
  • OSTEOPOROSIS
  • impaired growth and pubertal development
26
Q

What cardiac condition may develop with IRON overload?

A

arrhythmias

  • cardiomyopathy
  • pericarditis
27
Q

Can liver disease occur with iron overload?

A

yes

—–CIRRHOSIS and HCC

28
Q

What genetic change is seen with Hb in sickle cell anaemia?

A
  • point MUTATION codon 6 of globin gene, changing glutamine to valine> Beta-S globin prodn

—2 alphas and 2 beta-S = HbS

29
Q

What is bad about Hbs?

A

Can polymerise when exposed to LOW oxygen levels for a prolonged period of time
—–distorting the red cell and damaging the membrane

30
Q

When may a carrier of the sickle cell trait become symptomatic ?

A
  • SEVERE hypoxia seen under anaesthesia and at HIGH altitudes
  • –HbS <50%; normal blood film
31
Q

What vascular problems may arise with sickle cell anaemia?

A
  • EPISODE OF TISSUE infarction d.t vascular occlussion (sx depend on SITE and severity; pain is SEVERE)
  • —chronic hemolysis
  • —-REPEATED SPENIC INFARCTS > HYPOSPLENISM
32
Q

How to manage sickle cell anaemia?-

A
  1. prophylactic penicillin, vaccinations (d.t hyposplenism; risk of infection)
  2. folic acid supplement (incr. rbc turnover)
  3. hydroxycarbamide (reduces severity of diseaseby inducing HbF prodn)
  4. regular transfusion to prevent stroke
33
Q

What ivx are done with hemoglobinopathies?

A

FBC, Hb, Red cell indices

Blood film
ethnic origin
—–perform HPLC /electrophoresis (to quantify Hb present)

34
Q

In what types of Hb do alpha globin chains exist in?

In which condition may these types be affected?

A

HbA
HbA2
HbF

Alpha-thalassaemia

35
Q

Would HbH Disease patient need transfusion?

A

YES

—-d.t eventual jaundice and splenomegaly

36
Q

Name the most severe form of Alpha thalassaemia.

Why is it severe?

A
  • Hb Barts Hydrops Fetalis Syndrome

- -as NO alpha genes are inherited from either parents> minimal or NO alpha chain prodn (HbF and HbA can’t be made)

37
Q

What is considered as a high risk of a Hb Barts Fetalis Syndrome?

A
  • if BOTH prents are from SE asia
38
Q

Anything done to avoid risk of Hydrops Foetalis?

A
  • antenatal screening may help!
39
Q

Which Hb type is affected in Beta thalassaemia?

A

HbA

2 ALPHA chains and 2 beta chains

40
Q

How does the beta thalassaemia trait present as?

A

raised HbA2 (is diagnostic)

  • asymptomatic
  • no/mild anaemia
  • low MCV/MCH
41
Q

Which beta thalassaemia types requires blood transfusion?

A

Beta- thalassaemia Intermedia

Beta- thalassaemia Major (lifelong)

42
Q

What is seen on Hb analysis of beta-thalassaemia Major?

A
  • No HbA

- Mainly HbF

43
Q

What are physical signs of extramedullary hematopoiesis?

A
  • frontal bossing
  • spinal cord compression
  • spikey appearance of skull on xray
44
Q

How severe is iron overload, IIary to transfusions?

A
  • VERY
  • similar to hemachromatosis (but early onset and worse)
  • -BONE marrow transplant may be an OPTION !
45
Q

Why does iron overload occur with blood transfusion?

A
  • because there is 250mg of IRON per unit of RED cells

- —-chronic anaemia DRIVES incr. iron absorption

46
Q

How to manage IRON overload?

A
  • can’t do venesection (already anaemic)

- —> IRON chelating drugs (Desferrioxamine) ! —-enhances iron excretion

47
Q

Name the diff. iron chelating agents.

A
  1. Desferrioxamine (IV/s.c); can cause ocular/ ototoxicity at HIGH doses
  2. Deferipone (Oral)
    - -> better at removing CARDIAC iron
48
Q

What are the S.E of deferipone?

A
  • -> 1% agranulocytosis
  • —arthralgia
  • —-GI upset
49
Q

Why are transfusion pts predisposed to SEPSIS?

A
  • d.t excessive iron store

- —bacteria LOVES iron

50
Q

List other complications of transfusion.

A
  1. Viral infection
  2. Alloantibodies
  3. Transfusion Rxns
51
Q

What occurs genetically in Sickle Cell Anaemia?

A
  • 2 abnormal beta genes

- —-HbS >80% (no HbA)

52
Q

What is meant by sickle crisis?

A
  • seen in HbSS pts

- —the sickle cells begin to OCCLUDE the small vessels, d.t the loss of the biconcave rbc shape > tissue infarctions

53
Q

What makes sickle crisis worse?

A
  • Hypoxia
  • Dehydration
  • INfection
  • Cold exposure
  • stress/ fatigue
54
Q

How to treat acute sickle crisis?

A
  • opiate analgesia
  • hydration
  • oxygen
  • rest
  • ANTIBIOTICS (evidence of infection)
  • –red cell exchange transfusion —-if isckle crisis in brain/ lung
55
Q

What is the Long-term management for Sickle cell?

A
  1. Prophylactic Pencillin d.t Hyposplenism
  2. Folic acid supplments (incr. in RBC turnover)
  3. Hydrocycarbamide (induces HbF prodn)
  4. regular transfusion
56
Q

D.t Hyposplenism, what other vaccinations are done?

A

pneumococcus, meningococcu and hemophilus

57
Q

Best way to dx SICKLE CELL ANAEMIA?

A

HPLC

- Hb High performance liquid chromatography

HEMATOLOGY (20 decks)

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