Brainscape's Knowledge GenomeTM

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


See full index

CR2 > Macrolytic and haemolytic > Flashcards

Macrolytic and haemolytic Flashcards

1
Q

What is vitamin B12 also called, and why is it needed?

A

Vit. B12 = cobalamin

Needed for the synthesis of myeline + assists in DNA synthesis

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

What are the symptoms of vitamin B12 deficiency?

A 
Fatigue
Lethargy
Depression
Poor memory
Breathlessness
Headaches
Pale skin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What type of anaemia is caused by B12 and folate (Vit B9) deficiency?

A

Macrolytic anaemia

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

What can be measured that will indicate B12 deficiency?

A

Measure methylmalonic acid

Will increase when B12 is deficient

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

What are the functions of B12?

A
  • Methionine synthase uses B12 to transport a methyl group from 5-methyltetrahydrofolate –> homocysteine to become tetrahydrofolate (THF) and methionine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the function of THF, how might it be obtained in the diet?

A

THF plays a role in DNA synthesis (therefore less efficient production of THF in cells with rapid turnover)

May be obtained through dietary folate

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

Compare B12 and B9 in terms of how long they are stored and where they are absorbed.

A

B12:

  • stored for 3 years
  • absorbed in the terminal ileum

B9:

  • stored for 4 months
  • absorbed in the duodenum and jejunum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Explain how B12/B9 deficiency can lead to anaemia S+S.

A

B12/B9 deficiency —> DNA synthesis impaired —> cells fail to divide —> overlarge red cells —> increased rate of destruction of red cells —> anaemia S+S

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

Describe how vitamin B12 is absorbed.

A
  • Intrinsic factor is released by parietal cells in the stomach mucosae
  • B12 then binds to IF = IF-B12 complex (formed in the stomach)
  • Then absorbed in the terminal ileum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How might the blood count, blood film and biochemistry in B12 and B9 deficiency appear?

A

Blood count:

  • reduced Hb
  • high MCV
  • reduced WBC + platelets

Blood film:

  • oval macrophages
  • hypersegmented
  • neutrophils

Biochemistry:

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

What are the potential causes of vitamin B12 deficiency?

A
  1. Nutritional - unbalanced/unsupplemented diets
  2. Malabsorption:
    - Gastric: pernicious anaemia, surgical gastrectomy
    - Intestinal: ileal disease (Crohn’s)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is pernicious anaemia and how common is it?

A

Autoimmune condition
Antibodies produced against parietal cells + IF
This leads to gastric atrophy, reduced acid secretion and reduced IF secretion

Occurs in ~1-2% of the population >60 y/o (more common in females)

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

What are the clinical features of pernicious anaemia?

A
  • Insidious: gradual onset, but fatal if left untreated
  • Glossitis: inflammation of the tongue
  • Mild jaundice
  • Neurological symptoms (peripheral neuropathy, damage to sensory and motor tracts, dementia, optic atrophy)

*Macrocytic anaemia, hypersegmented neutrophils and reduced serum B12

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

How is pernicious anaemia treated?

A

IM B12 injections every 3 months for life

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

What are the potential causes of folate deficiency?

A
  1. nutritional: old age, poverty, alcoholism
  2. malabsorption: coeliac, crohn’s
  3. pregnancy
  4. others: anticonvulsants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What causes haemolytic anaemias? Where are the 3 main sites of pathology?

A

Shortened survival of RBCs
3 sites of pathology:
1. Membrane: hereditary spherocytosis, oxidising agents, antibodies against RBC membrane
2. Haemoglobin: abnormal structure (sickle cell), imbalance in alpha:beta synth (thalassaemia)
3. Enzymes: G6PD deficiency, etc.

17
Q

How might someone with haemolytic anaemia present?

A

Pallor
Jaundice (increased levels of bilirubin)
Gallstones
Splenomegaly

18
Q

What is hereditary spherocytosis? What is the inheritance pattern? What would investigations of the blood show?

A
  • defect in protein of the RBC cytoskeleton
  • high fragility and more prone to degradation
  • autosomal dominant
  • chronic haemolytic anaemia
  • reduced Hb, increased LDH, increased serum bilirubin
19
Q

What is G6PD deficiency? What is the inheritance pattern?

A
  • Hb and other RBC proteins become oxidised over time due to high PO2
  • prolongs life of RBC preventing/reversing oxidising Hb
    X-linked
  • symptoms present when exposed to a trigger (food, bacteria, drugs etc.)
20
Q

What is autoimmune haemolytic anaemia (AIHA)? What type of antibodies are involved?

A
  • IgG antibodies react with RBC membrane proteins
  • Attaches to RBCs and label them for destruction
  • removed by spleen = extravascular haemolysis
  • usually idiopathic but can be caused by drugs, CT disease or blood transfusion
21
Q

Describe the procedure of the direct Coombs/antiglobulin test and why it is done.

A
  • Check if there if antibody on a red cell
  • Procedure:
    1. blood sample taken from pt with AIHA
    2. patient’s washed RBCs are incubated with antihuman antibodies
    3. +ve result: RB C agglutination (antihuman antibodies bind to human antibodies on RBCs)

CR2 (36 decks)

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