Brainscape's Knowledge GenomeTM

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


See full index

I need to learen > B12 and folate deficiencies > Flashcards

B12 and folate deficiencies Flashcards

1
Q

What are the roles of vitamin B12 and folate

A

DNA synthesis
Integrity of the nervous system

DNA synthesis
Homocystine metabolism

Both are needed for production of deoxythymidine

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

Which cells are affected by a vit B12/folate deficiency

A 
All rapidly dividing cells 
Bone marrow
Epithelial surfaces of mouth and gut
Gonads
Embryos
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the clinical features of a vit B12/folate deficiency

A 
Anemia: weak, tired, short of breath (macrocytic and megaloblastic)
Jaundice
Glossitis and angular cheilosis
Weight loss, change of bowel habit
Sterility
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the causes of macrocytic anaemia

A

Vitamin B12/folate deficiency
Liver disease or alcohol
Hypothyroid
Drugs e.g. azathioprine
Haematological disorders (Myelodysplasia,
aplastic anemia
Reticulocytosis e.g. chronic haemolytic anemia)

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

What is the difference between macrocytic and megaloblastic anaemia

A

Macrocytic - average red cell size is above normal range

Megaloblastic - morphological change in red cell precursors in the bone marrow.

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

Define megaloblastic anaemia

A

asynchronous maturation of the nucleus and cytoplasm in the erythroid series
Maturing red cells seen in bone marrow

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

Describe the peripheral blood in megaloblastic anaemia

A

Anisocytosis
Large red cells
Hypersegmented neutrophils
Giant metamyelocytes

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

Give a source of folate

A

Fresh leafy vegetables

Destroyed by overcooking/canning/processing

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

What causes an increased demands in folate

A

PHYSIOLOGICAL
Pregnancy
Adolescence
Premature babies

PATHOLOGICAL
Malignancy
Erythoderma
Haemolytic anaemias

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

How is folate deficiency diagnosed/assessed

A

History (diet, alcohol, illness)
Examination (skin disease, alcoholic liver disease)

Lab
FBC and film
Folate levels in the blood

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

What are the consequences of folate deficiency

A

Megaloblastic, macrocytic anaemia
Neural tube defects in a developing foetus
Increased risk of thrombosis in association with variant enzymes involved in homocysteine metabolism

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

Give examples of neural tube defects

A

Spina bifida

Anencephaly

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

What are very high homocysteine levels associated with

A

Atherosclerosis
Premature vascular disease
High rate of thrombosis

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

What are mildly elevated levels of homocysteine associated with

A

Cardiovascular disease

arterial or venous thrombosis

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

What are the classic features of high homocysteine

A 
Tingling in fingers (parasthesiae)
Family history of auto-immune disease
Glossitis (inflamed tongue)
Premature grey hair 
Falls over when eyes closed
Romberg's sign (loss of proprioception)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the neurological consequences of B12 deficiency

A

Bilateral peripheral neuropathy
Subacute comined degeneration of the cord (Posterior and pyramidal tracts of the spinal cord)
Optic atrophy
dementia

17
Q

What will the classic clinical history of a patient with B12 deficiency look like

A 
Paraesthesiae
Muscle weakness
Difficult walking
Visual impairment
Psychiatric disturbance
Absent reflexes and upping plantar response
18
Q

What are the causes of B12 deficiency

A

Poor absorption
Reduced dietary intake (vegans at risk)
Infections/infestations (abnormal bacterial flora, tropical sprue, fish tapeworm)

19
Q

Describe the normal B12 absorption

A

In small intestine
1. Slow and inefficient (1%) in the duodenum
2. Combination with intrinsic factor from the stomach parietal cells (99%) to bind to ileal receptors
Storage and excretion when stores are in excess

20
Q

Which 3 things are essential for B12 absorption

A

Intact Stomach
Intrinsic factor
Functioning small intestine

21
Q

What may a reduction in intrinsic factor be caused by

A

Post gastrectomy
Gastric atrophy
Antibodies to intrinsic factor or parietal cells

22
Q

Describe pernicious anaemia

A

Autoimmune condition associated with severe lack of intrinsic factor
Peak age = 60
Family history

23
Q

Describe the antibodies in pernicious anaemia

A

Intrinsic factor antibodies (can be found in other conditions)

Parietal cell antibodies
90% of adults, 16% normal females >60yrs

24
Q

What may cause impaired B12 absorption

A

Reduction in intrinsic factor

Diseases of the small bowel (terminal ileum)

25
Q

Which disease of the small bowel can cause impaired B12 absorption

A

Crohns
Coeliac disease
Surgical resection

26
Q

Which infections can cause impaired B12 absorption

A

H. Pylori
Giardia
Fish tapeworm
Bacterial overgrowth

27
Q

Which drugs are associated with low B12

A

Metformin
Proton pump inhibitors e.g. omeprazole
Oral contraceptive pill

28
Q

What are the tests done for patients with low B12

A
  1. Antibodies to parietal cells and intrinsic factor
  2. Anitbodies for coeliac disease
  3. Breath test for bacterial overgrowth
  4. Stool for H Pylori
  5. Test for Giardia
29
Q

What are the possible reasons for no B12 being found in the urine in the shilling test

A

B12 is not being absorbed (pernicious anaemia or small bowel disease)

B12 deficiency was not corrected before test

30
Q

What is the shilling test

A

Prior to test, replenish the stores (drink radio labelled B12 and measure excretion)
Repeat test with intrinsic factor added
Measure excretion of B12

31
Q

What should be done if there is a classic case of B12 deficiency but B12 is normal

A

Measure methylmalonyl acid
Measure homocysteine
Look for anti-intrinsic factor antibodies

32
Q

What is the treatment for B12 deficiency

A

IM injections of B12

3x a week for 2 weeks then 3 months

I need to learen (23 decks)

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