Nutritional Anaemias Flashcards

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1
Q

What is anaemia?

A

“Anaemia is a condition in which the number of red blood cells (and consequently their oxygen-carrying capacity) is insufficient to meet the body’s physiologic needs.”

Insufficient oxygen carrying
capacity is due to reduced haemoglobin concentration as seen with insufficient RBC

WHO: Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity.

Anaemia caused by lack of essential ingredients that the body acquires from food sources

Iron deficiency
Vitamin B12 deficiency
Folate deficiency

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2
Q

What does the Maturation of red blood cells require?

A

Vitamin B12 & folic acid; important for DNA synthesis
Iron; important for Haemoglobin synthesis

Vitamins
Cytokines (erythropoeitin)
Healthy bone marrow environment

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3
Q

Why is there not enough haemoglobin? (what factors play a role in that to investigate in someone with anaemia?)

A

Failure of Production(of Hb by the bone marrow) hypoproliferation
Reticulocytopenic- you see a reduction in the number of reticulocytes (slightly premature red blood cells) so if anaemic there will be even a lack of the ‘baby red blood cells’ as bone marrow cant even produce to try compensate

Ineffective Erythropoiesis

Decreased Survival
Blood loss, haemolysis, reticulocytosis

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4
Q

Using the MCV- mean cell volume, what can be some of the causes of anaemia?

A
MICROCYTIC: (RBCs smaller than normal)
Iron deficiency 
(heme deficiency)
Thalassamia 
(globin deficiency)
Anaemia of Chronic Disease
NORMOCYTIC:
Anaemia Chronic Disease
Aplastic Anaemia
Chronic Renal Failure
Bone marrow infiltration
Sickle Cell Disease
MACROCYTIC:
B12 Deficiency
Folate Deficiency
Myelodysplasia
Alcohol induced
Drug Induced
Liver Disease
Myxoedema

Reticulocyte count then adds further clue as to failure of production or increased losses

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5
Q

What is iron essential for?

A

Essential for O2 transport
Most abundant trace element in body

Daily requirement for iron for erythropoeisis varies depending on gender and physiolgical needs

Recommended intake assumes 75% of iron is from heme iron sources (meats, seafood). Non-heme iron absorption is lower for those consuming vegetarian diets, for whom iron requirement is approximately 2-fold greater.

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6
Q

Where does your iron come from/what do you do with it etc?

A

iron comes from diet, absorb it into your duodenum, body then produces protein called transferrin- transport takes iron where needed, most iron in your body sits within your red blood cells, quite a bit in liver and muscle too,
only main ways of losing iron is from menstruation or gi tract, you cant naturally get rid of iron easily (unlike vit c where you pee out excess) so your body chooses how much to absorb from intake
so iron regulation is within absorption

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7
Q

What is iron absorption regulated by?

A

Regulated by GI mucosal cells and hepcidin
Duodenum & proximal jejunum
Via ferroportin receptors on enterocytes
Transferred into plasma and binds to transferrin

Amount absorbed depends on type ingested
Heme, ferrous (red meat, > than non-heme, ferric forms Heme iron makes up 10-20% of dietary iron
Other foods, GI acidity, state of iron storage levels and bone marrow activity affect absorption

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8
Q

What is hepcidin and and what does it do?

A

“ the iron-regulatory hormone hepcidin and its receptor and iron channel ferroportin control the dietary absorption, storage, and tissue distribution of iron…

Hepcidin causes ferroportin internalization and degradation, thereby decreasing iron transfer into blood plasma from the duodenum, from macrophages involved in recycling senescent erythrocytes, and from iron-storing hepatocytes.
Hepcidin is feedback regulated by iron concentrations in plasma and the liver and by erythropoietic demand for iron.”

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9
Q

Where is iron transported from and where does it go?

A

Iron transported from enterocytes and then either into plasma or if excess iron stored as ferritin

In plasma: attaches to transferrin
and then transported to bone marrow binds to transferrin receptors on RBC precursors

A state of iron deficiency will see reduced ferritin stores and then increased transferrin

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10
Q

What are some symptoms and signs of Iron Deficiency Anaemia?

A

Symptoms
fatigue, lethargy, and dizziness

Signs
pallor of mucous membranes, 
Bounding pulse, 
systolic flow murmurs, 
Smooth tongue, koilonychias
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11
Q

What do you find with regards to rbc size with b12 and folate deficiency?

A

Macrocytic anaemia-Low Hb and high MCV with normal MCHC (mean cell Hb conc) so fewer red cells and bigger essentially

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12
Q

What is macrocytic anaemia?

A
Megaloblastic : 
Low reticulocyte count
 causes:
Vitamin B12/Folic acid deficiency
Drug-related 
	(interference with B12/FA metabolism)
Nonmegaloblastic
causes:
Alcoholism ++
Hypothyroidism
Liver disease
Myelodysplastic syndromes
Reticulocytosis (haemolysis)
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13
Q

Why is it more common to have a folate deficiency in comparison to a b12 deficiency? - looking at the average western diet
(excluding vegan diets)

A

B12 source- animal and dairy produce
folate source: vegetables and liver

when cooking, there is more nutritional loss of folate (60-80%) in comparison to B12(10-30% loss)
also we get an abundance of b12 (7-30mcg) in comparison to the daily requirement for it (1-2mcg)
whereas we get just about what is required of folate - less in excess , we get about 200-250mcg whereas the daily requirement is 100-150mcg.
also the average body stores of folate is much shorter (3-4 months, 10-12mg) so needs replenishing more often, hence it is more common to find a folate deficiency.
we store b12 for 2-4 years on average (2-3mg)

the absorption site of b12 is the ileum via the intrinsic factor
the absorption site of folate is the duodenum and jejunum

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14
Q

What is vitamin b12 also known as and what, along with folic acid, are they important for?

A

Vitamin B12 = cobalamin
Folic acid

Both important for the final maturation of RBC and for synthesis of DNA

Both needed for thymidine triphosphate synthesis

Folate necessary for DNA Synthesis:
Adenosine, guanine and thymidine synthesis

Essential co-factor for methylation in DNA and cell metabolism

Intracellular conversion to 2 active coenzymes necessary for the homeostasis of methylmalonic acid (MMA) and homocysteine

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15
Q

What foods contain b12 and what are the recommendations with regards to intake?

A

Foods containing vit B12:
Animal sources: Fish, meat, dairy

UK intake recommendations are 1.5mcg/day
EU: 1mcg/day and USA: 2.4mcg/day
average western intake 5-30mcg/day
Body (liver) storage: 1-5mg so many years for deficiency

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16
Q

What does vitamin b12 require for absorption?

A

Requires the presence of Intrinsic Factor for absoprtion in terminal ileum

IF made in Parietal Cells in stomach
Transcobalamin II and Transcobalamin I transport vitB12 to tissues

17
Q

What is pernicious anaemia?

A

Essentially, no matter how much vitamin b12 you are eating, you cannot absorb it.

Autoimmune disorder
Lack of Intrinsic factor
Lack of B12 absorption

Gastric Parietal cell antibodies
Intrinsic factor antibodies

18
Q

What do clinical consequences of anaemia include?

What treatments are there for this?

A
Brain: cognition, depression, psychosis
Neurology: myelopathy, sensory changes, ataxia, spasticity (SACDC)
Infertility
Cardiac cardiomyopathy
Tongue: glossitis, taste impairment
Blood: Pancytopenia

Treatment:
Treat the underlying cause **

Iron – diet, oral, parenteral iron supplementatin, stopping the bleeding

Folic Acid – oral supplements

B12 – oral vs intramuscular treatment