Brainscape's Knowledge GenomeTM

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


See full index

CR3 > Sickle Cell and Haemoglobinopathies > Flashcards

Sickle Cell and Haemoglobinopathies Flashcards

1
Q

What is normal Hb?

A

HbA

Adult haemoglobin

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

What is adult Hb made up of?

A

4 globin chains

  • 2 alpha
  • 2 beta

4 haem molecules, one bound to each chain

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

Define haemoglobinopathies

A

Structural Abnormalities affecting globin chains in Hb molecules

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

Example of haemoglobinopathy

A

Sickle cell disease

Presence of HbS in beta chain due to mutation

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

Causes of thalassaemia?

A
  • reduced/absent production of beta or alpha chain = ineffective erythropoiesis
  • effects of anaemia
  • effects of iron overload in transfused patients
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Cause of sickle cell

A

HbS

Glutamate substituted by valine in position 6 of beta gene

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

Inheritance of sickle cell

A
  • autosomal recessive
  • mendelian mode of inheritance
  • carries = asymptomatic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Pathophys of sickle cell

A
  • polymerisation = sickling
  • this results in vaso-occlusion/infarction AND haemolysis
  • precipitated by hypoxia, HbS conc/dehydration, acidosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Clinical diagnosis of sickle cell

A

FH

Recurrent pain

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

Lab diagnosis of sickle cell

A
  • anaemia
  • haemolysis (high bilirubin, high LDH, raised reticulocytes, undetectable haptoglobin)
  • blood film
  • haemoglobin electrophoresis/sickle solubility test
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Sickle solubility test

A
  • negative = can see lines behind tube

- positive = cannot see lines behind tube

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

Emergency presentations/complications of sickle cell

A

1) pain/acute painful crisis
2) splenic sequestration
3) aplastic crisis
4) overwhelming sepsis
5) acute chest syndrome
6) fat embolism syndrome/mutli organ failure
7) priapism (splenic sequestration mechanism)
8) acute infarct

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

What can an acute infarct cause?

A

Stroke
MI
Acute visual loss
Acute renal failure

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

Presentation of painful sickle cell crisis

A
  • rapid onset
  • bone pain
  • bone marrow infarction
  • hours-weeks variable
  • fever, bone tenderness, swelling, hypertension, tachycardic, tachypnoea
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Precipitating factors of painful sickle cell crisis

A
  • infections
  • skin cooling
  • dehydration
  • deoxygenation
  • stress
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Analgesia procedures for sickle cell crisis

A
  • within 30min of presentation
  • parenteral opiates
  • re-assess and repeat as necessary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What to monitor in sickle cell crisis?

A
  • vital signs
  • temp
  • fluid intake
  • analgesia use and pain score
  • sedation/urinary retention/restlessness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Investigations in sickle cell crisis

A
  • FBC and reticulocytes
  • U&E/LFT
  • LDH
  • CRP
  • Blood cultures
  • CXR
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is acute chest syndrome?

A
  • acute illness
  • new infiltrate on CXR
  • respiratory syndromes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Triggers of acute chest syndrome

A
  • surgery/anesthesia
  • pregnancy
  • increased risk of chronic lung disease
  • increased risk of death
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Sickle cell positive feedback symptoms

A

hypoxi, inflammation and acidosis = vaso-occlusion within pulmonary microvasculature = fat embolism and pulmonary thrombi

BUT vaso-occlusion causes more hypoxia/inflammation/acidosis

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

Management of sickle cell crisis

A
  • analgesia
  • incentive spirometry = reduces ACS
  • O2 therapy
  • fluids
  • AB
  • transfusion
23
Q

Which transfusion to give in sickle cell crisis

A
  • TUT = mild ACS

- ExTx gen = moderate/severe ACS

24
Q

Overwhelming hyposplenic sepsis cause

A

Pneumococcal
Meningococcal
Haemophilus influenzae

25
Q

Overwhelming hyposplenic sepsis symptoms

A

Febrile
Coma
Altered sensorium
Seizures

26
Q

Overwhelming Hyposplenic sepsis treatment

A

Urgent AB treatment
Prophylactic Pen V
Vaccination

27
Q

Overwhelming Hyposplenic sepsis who?

A

<3 years

splenic auto-infarction from very young age = functional asplenia

28
Q

Sequestration define

A
  • acute deterioration of anaemia
  • painful enlargement of spleen
  • drop in Hb>2g/L
29
Q

Sequestration who?

A
  • children

- <2years

30
Q

Sequestration management

A
  • early detection
  • parental education
  • urgent blood transfusion
  • splenectomy
31
Q

Sequestration prognosis

A
  • recurrence = 50%

- mortality = 12%

32
Q

Aplastic crisis cause

A

infection with HPV B19

  • infection of red cell precursors in bone marrow = pure red cell aplasia = low reticulocytes
  • Hb nadir 15 days post infection
33
Q

Aplastic crisis who

A
  • childhood illness common

- slapped cheek disease

34
Q

Aplastic crisis management

A

Urgent blood treatment

35
Q

Inheritance of thalassaemia

A
  • autosomal recessive
  • mutations = deletion of alpha globin or beta globin genes
  • carries asymptomatic = thalassaemia minors
36
Q

What anaemia do you get with thalassaemia?

A

microcytic hypochromic

with haemolysis

37
Q

Beta thalassaemia major define

A
  • deletion of beta globin gene
  • lack of production of beta chains
  • homozygous
38
Q

How to treat beta thalassaemia major?

A
  • transfusion dependent

- get secondary iron overload

39
Q

Clinical features of beta thalassaemia major?

A
  • severe anaemia
  • growth failure
  • HF as high output
  • bone marrow expansion
  • death in 1st and 2nd decade without transfusion
  • regular transfusions from early to maintain Hb>10
40
Q

Consequences of bone marrow expansion in beta thalassaemia major?

A
  • thalassaemic facies
  • poor dentition
  • interdental separation
  • hair on end appearance on skull x-ray
  • bone disease
  • extramedullary haemopoiesis
41
Q

Haemosiderosis

A
  • tranfusional iron overall
  • without chelation
  • effects appear by end of first decade
42
Q

Clinical features of iron overload

A
  • impaired growth
  • infertility
  • hypoparathyroidism
  • cardiomyopathy
  • cardiac failure
  • hepatic cirrhosis
  • diabetes mellitus
  • hypogonadism
  • sudden arrhythmia = death in teens/early 20s
43
Q

How to assess iron status?

A
  • liver biopsy (invasive)
  • serum ferritin (non specific)
  • cardiac/liver MRI
44
Q

Gold standard to assess iron status for iron overload

A

cardiac/liver MRI

45
Q

Iron chelating agents

A
  • desferoxamine (continuous infusion)
  • deferiprone (oral)
  • deferassirox (oral)
  • combination
46
Q

Which thalassaemia is worse

A

Beta worse than alpha

47
Q

Alpha thalassaemia prevalent areas

A

China
SE Asia
Eastern Mediterranean
Middle East

48
Q

Inheritance of alpha thalassaemia

A

2 sets of genes located on chromosome 16

2 inherited from each parent

49
Q

Alpha thalassaemia minor

A
  • asymptomtic
  • mild microcytic anaemia
  • 2 from 1 parent or 1 from both
50
Q

Hb H disease

A
  • symptomatic
  • haemolytic and microcytic anaemia
  • splenomegaly
  • 3, 2 from 1 parent, 1 from other
51
Q

Alpha thalassaemia major

A
  • 2 from each parents
  • incompatible with life
  • hydrops fetalis
52
Q

Thalassaemia Intermedia

A
  • anaemia
  • not transfusion dependent
  • risk of iron overload as increased absorption
  • Beta thalssaemia major with alpha thalassaemia trait
  • beta thalssaemia trait with triplicate alpha chains
  • e.g. delta-beta thalassaemia
  • e.g. HbE beta thalassaemia
53
Q

Antenatal Screening

A

Heel Prick test

  • identify all pregnancies with haemoglobinopathy risk
  • offer partner screening
  • genetic counselling to affected
54
Q

Children at birth with sickle cell management?

A
  • pencillin prophylaxis
  • immunisation
  • parent education

CR3 (30 decks)

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