B12 And Folate Deficiencys Flashcards
How can anaemia form
The issues with the bone marrow
The abnormal erythropoiesis
The abnormal haemoglobin synthesis
Excessive blood loss
Abnormal structure, function and shape of the cells
What is part of the abnormalities in erythropoiesis
Panocytopenia
Aplastic anaemia (when would not produce the mature blood cells)
Exposure of the bone marrow to benzene, infection, ionising radiation, autoimmune
What is part of the haemoglobin synthesis issues
The iron deficiency
The anaemia of chronic disease (so would not have the release of the iron, would mainly be stored and therefore cannot be used)
What is macrocytic anaemia
When would have the deficiency in the B12 (colbamin) or the folates
Would not be able to have the DNA synthesis
Would produce the megaloblasts, that would have the immature nuclei
This would then allow the mean cell volume to increase
What is a megaloblast
Large cell that would have the uncondensed chromatin material as a result of the impaired DNA synthesis
What conditions can megaloblastic anaemia cause
The beefy tongue
The angular glossitis (inflammation of the skin) and ‘lemon yellow skin’
What is macrocytosis
The increase in the mean cell volume above the normal range
So have the megaloblasts with the immature nuclei
What is the issue with metformin
Medication that would be taken for diabetes
Would decrease the absorption of the B12 into the body
This is bad as B12can ONLY come from the animal products (body doesn’t produce)
How would B12 be absorbed by the body
First on proteins
released
complex with haptocorrin
Pancreatic protease breaks down
Glycoprotein intrinsic factor bind
Internalised binds to transcolbamin (goes to the blood to be used)
Why do we need B12
Helps with the formation of myelin (not have would get peripheral neuropathy reversible)
Important in pregnancy for the growth of foetus
Makes DNA
Heart health
Digestion aid
Where would you get folate’s from and why is is needed
The Leafy greens as made by BACTERIA AND PLANTS
Needed for DNA methylation (synthesis or DNA and RBCs]
What happens when have the deficiency in folates
Neural tube defects
Symptoms of anaemia
What two metabolic pathways would B12 be needed
1) transfer of the methyl group from L-methyl malonyl COA to form succinyl COA
2) Transfer of methyl group from FH4 (tetrahydrofolate) to homocysteine to form methionine
(If do not have this second would lead to the folate trap)
What Happens to the methylation reactions when would have a B12 deficiency
-The increased levels of homocysteine as cannot have the methyl transfer to form methionine (FOLATE TRAP)
-folate trap - functional folate deficiency, no nucleotide synthesis for DNA synthesis
-elevated levels of L-methyl malonyl COA (not forming the succinyl COA)
How do you treat megaloblastic anaemia (coming from the folate and B12 deficiency)
Folic acid administered
BUT
Masks B12 that can lead to the bad neural disorders (need to treat B12 too)
What drug would be given to treat those who are B12 deficient (with neurological issues)
Hydroxocolbamin
1mg 3x a week for 2 weeks
Dietary advice too
What is pernicious anaemia
When would have the deficiency in the intrinsic factor
(Produced in the stomach pareital cells)
Would not have the b12 taken up in the Illeum
Where does the haptocorrin (R-binder) act in the body
The stomach
Where’s does transcolbamin act
The portal vein (liver)
What other issues can the deficiency of B12 cause
The degeneration of the posterior and lateral aspects of the spinal cord
Tingling and numbness in the leg, arms and the trunk
Why is the folate trap bad
Folates trapped in stable form
Not used for nucleotide synthesis
Inflammation associated
What are the other causes of the macrocytic anaemias
Pregnancy
Smoking
Drugs (hydroxycarbamide, antimetabolites, methotrexate, azathioprim)
Severe thyroid deficiency
Where would the intrinsic factor be released from
The parietal cells (of the fundus)
What would you need succinyl-coa
Would be needed for reactions such as the kerbs cycle
