Brainscape's Knowledge GenomeTM

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


See full index

Year 3 > Vitamin B12 and/or folate deficiency (CH) > Flashcards

Vitamin B12 and/or folate deficiency (CH) Flashcards

1
Q

What is the role of vitamin B12 (cobalamin)?

A

RBC formation and myelination of nervous system

(Co-factor in DNA synthesis - needed for normal haematopoiesis and bone marrow function)

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

What is vitamin B12 also known as?

A

Cobalamin

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

Where do we get vitamin B12 from?

A

Animal + dairy products (meat, poultry, eggs, milk)

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

Where is vitamin B12 absorbed?

A

Terminal ileum, and requires intrinsic factor (IF)

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

What are the causes of vitamin B12 deficiency? (4)

A
  • pernicious anaemia - autoantibodies against IF or gastric parietal cells and increases risk of gastric cancer - may have Hx of autoimmune disease
  • post-gastrectomy
  • vegan diet
  • terminal ileum affected e.g. Crohn’s, Coeliac or ileocaecal resection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is pernicious anaemia?

A

Autoantibodies against intrinsic factor (causing vitamin B12 deficiency) or gastric parietal cells and increases risk of gastric cancer

May have Hx of autoimmune disease

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

What does vitamin B12 deficiency depend on?

A

Stores of B12 remain in body for years, therefore deficiency depends on chronic, long-term deficiency

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

What does prolonged vitamin B12 deficiency lead to? (2)

A
  • neurological disorders - dementia, sub-acute combined degeneration of spinal cord (SACD), peripheral neuropathy
  • haematological disorders - megaloblastic anaemia, leukopenia, thrombocytopenia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is folate also known as?

A

Vitamin B9

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

What is the role of folate?

A

DNA synthesis and amino acid metabolism

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

What are the sources of folate? (5)

A
  • green leafy vegetables
  • fruit
  • liver
  • bread
  • cereal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the causes of folate deficiency? (4)

A
  • malabsorption e.g. small bowel disease due to IBD or Coeliac
  • malnutrition e.g. chronic alcohol use
  • increased requirement e.g. pregnancy
  • drug-related e.g. methotrexate (folate antagonist) or anti-epileptics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is maternal folate deficiency associated with?

A

Foetal neural tube defects (NTDs) e.g. spina bifida

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

How does vitamin B12 vs folate deficiency generally manifest?

A
  • B12 - megaloblastic anaemia +/- neurological and neuropsychiatric
  • folate - megaloblastic anaemia without neurological signs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the clinical features of B12 deficiency? (4)

A
  • anaemia signs - fatigue, pallor, SOB, glossitis & angular cheilitis (late)
  • peripheral neuropathy
    • tingling, numbness, paraesthesia in hands and feet
    • leg weakness
    • diminished proprioception and vibration sensation in feet
  • dementia
  • cognitive impairment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What signs of sub-acute combined spinal cord degeneration (SACD) can be seen in B12 deficiency? (3)

A
  • ataxia
  • decreased vibration sense
  • positive Romberg’s test
17
Q

What are the clinical features of folate deficiency? (4)

A
  • anaemia signs - fatigue, pallor, SOB, glossitis & angular cheilitis (late signs)
  • loss of appetite and weight loss - hallmark of folate deficiency, WL due to both loss of appetite and increased energy demands of ineffective erythropoiesis
  • Sx of underlying causes e.g. prolonged diarrhoea in IBD/Coeliac
  • foetal spina bifida (neural tube defect) - if maternal deficiency
18
Q

What can pernicious anaemia (B12 deficiency) present? (7)

A
  • gastric pain/discomfort
  • tiredness
  • dyspnoea
  • paraesthesia
  • sore red tongue
  • diarrhoea
  • mild jaundice
19
Q

What are the risk factors for B12 deficiency? (7)

A
  • age>65
  • gastric surgery (bypass/resection)
  • chronic GI disease
  • vegan/strict vegetarian diet
  • metformin use
  • H2 receptor antagonist or PPI
  • pernicious anaemia
20
Q

What are some risk factors for folate deficiency? (7)

A
  • age>65
  • low dietary folate intake
  • intestinal malabsorptive disorders (Crohn’s, Coeliac, bacterial overgrowth syndrome)
  • alcohol-use disorder
  • pregnant or lactating
  • drugs - methotrexate, trimethoprim, sulfasalazine, pyrimethamine, anticonvulsants e.g. phenytoin
  • congenital defects in folate absorption and metabolism
21
Q

What are the first-line investigations for B12 and folate deficiency?

A
  1. FBC - useful for severe and prolonged deficiency (macrocytic anaemia, high MCV, low Hct, may present as part of pancytopenia)
  2. peripheral blood smear - megalocytes, hypersegmented poly-morphonucleated cells
  3. serum vitamin B12
  4. reticulocyte count - differentiate B12 deficiency from haemolytic anaemia, if low –> decreased production (vs high in HA)
22
Q

What does FBC show in B12/folate deficiency? (4)

A
  • macrocytic anaemia
  • high MCV
  • low Hct
  • may present as part of pancytopenia
23
Q

What would a blood film show in B12 and folate deficiency?

A

Macrocytic megaloblastic anaemia - decreased Hb, increased MCV, hyperchromic RBCs, hypersegmented neutrophils

24
Q

What is reticulocyte count like in B12 and folate deficiency?

A

Low count (indicates decreased production) - distinguishes deficiencies from haemolytic anaemia

25
Q

What serum vitamin B12 levels indicate deficiency?

A
  • <148 picomols/L (<200 picograms/mL) = probable deficiency
  • 148-258 picomols/L (201-350 picograms/mL) = possible deficiency
  • > 258 picomols/L (>350 picograms/mL) = unlikely deficiency
26
Q

How do we test for pernicious anaemia (B12 deficiency)?

A

Test for autoantibodies: anti-IF (more specific), anti-GPC

27
Q

What tests may help diagnose B12 deficiency at an early, asymptomatic state?

A

Methylmalonic acid and homocysteine levels

28
Q

What do homocysteine levels show in B12 and folate deficiencies?

A

Elevated in both

29
Q

What does methylmalonic acid show in B12 and folate deficiencies?

A

Elevated in B12 deficiency and normal in folate deficiency

30
Q

What is holotranscobalamin like in B12 deficiency?

A

B12 bound to transcobalamin = low

31
Q

How do we manage vitamin B12 deficiency?

A
  • IM supplementation of B12 (hydroxycobalamin) - lifelong
    • if mild/ASx etc - oral cyanobobalamin/hydroxycobalamin
  • dietary supplementation of B12 + multivitamins - especially in older patients with poor diets
32
Q

How do we manage folate deficiency?

A

Oral folate (folic acid) supplementation, nutritional counselling to increase folate intake

33
Q

Why is folic acid given to pregnant women?

A

Risk of neural tube defects e.g. spina bifida and anencephaly if maternal folate deficiency

400mcg of folic acid until 12th week of pregnancy

34
Q

Why do we always replace B12 before folate (BeFore)?

A

Protects against sub-acute combined degeneration of spinal cord:

  • ataxia
  • positive Romberg’s test
  • distal sensory loss, impaired proprioception and vibration
  • hyperreflexia
  • absent ankle jerks/extensor plantars
  • tingling
35
Q

What are some complications of B12 deficiency?

A
  • neurological - cognitive, myelopathy (SC disease), neuropathy, SACD
  • haematological - anaemia, leukopenia, thrombocytopenia
  • low birth weight + preterm delivery

Year 3 (208 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions