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Mechanisms of disease > nutritional anemias > Flashcards

nutritional anemias Flashcards

1
Q

what is anaemia

A

condition which number of RBC is insufficient to meet bodies physiologic needs

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2
Q

what is haemoglobin

A

iron containing oxygen transport metalloprotein within RBCs

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3
Q

normal erythropoiesis

A

maturation of RBC require:

  • vitaminB12 and folic acid, DNA synthesis, iron and haemoglobin synthesis

vitamins
cytokines
healthy bone marrow environment

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4
Q

anaemia: mechanisms of action

A

failure of production = hypo proliferation reticulocytopenic

ineffective erythropoesis

decreased survival = blood loss, haemolysis, reticulocytosis

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5
Q

describe microcytic

A

iron deficiency
thalassamia
anaemia of chronic disease

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6
Q

describe normocytic

A

anemia chronic disease

aplastic anaemia

chronic renal failure

bone marrow infiltration

sickle cell disease

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7
Q

describe macrocytic

A

B12 deficiency
folate deficiency

myelodysplasia

alcohol induced
drug induced
liver disease
myxoedema

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8
Q

nutritional anemias

A

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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9
Q

describe iron

A

essential for O2 transport

most abundant trace element in body

daily requirement for iron for erythropoiesis varies depending on gender and physiological needs

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10
Q

describe the distribution of iron in adults

A
  1. plasma transferrin
    utilisation = muscle myoglobin or bone marrow

or storage iron in liver

reticuloendothelial macrophages

sloughed mucosal cells
desquamination/menstruation

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11
Q

iron metabolism

A

> 1 stable form of iron:

  • ferric states 3+ and ferrous states 2+

most iron in body as circulating Hb = 4 harm groups, 4 globin chains able to bind to 4 O2

storage and transport proteins = ferritin and haemosiderine = found in cells of liver, spleen and bone marrow

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12
Q

describe iron absorption

A

regulated by GI mucosal cells and hepcidin

duodenum and proximal jejunum

via ferroportin receptors on enterocytes

transferred into plasma and binds to transferrin

amount absorbed depends on type ingested
heme, ferrous
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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13
Q

iron regulation: hepcidin

A

hepcidin = hormone, receptor and iron channel ferroportin control dietary absorption, storage and tissue distribution of iron

hepcidin causes ferroprotin internalization and degradation, therefore decreases iron transfer into blood plasma from duodenum, from macrophages involved in recycling senescent erythrocytes and from iron storing hepatocytes

hepicidin is feedback regulated by iron conc in plasma and liver and by erythropoietic demand for iron

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14
Q

iron transport and storage

A

iron transported from enterocytes and either to 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

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

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15
Q

iron deficiency in anaemia lab results

A

ferritin = low

tf saturation = low

TIBC = high

serum iron = low/normal

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16
Q

causes of iron deficiency

A

not enough in:

  • poor diet
  • malabsorption
  • increased physiological needs

losing too much:

  • blood loss
  • menstruation, GI tract loss, parasites
17
Q

most common cause of IDA in women and men

A

blood loss from GI tract for men and postmenopausal women

18
Q

symptoms of anaemia

A

fatigue
lethargy
dizziness

pallor of mucous membranes 
bouding pulse 
systolic flow murmurs 
smooth tongue 
kolionychias
19
Q

b12 and folate deficiency

A

both have similar lab findings and clinical symptoms
found together or as isolated pathologies

macrocytic anaemia:
- low Hb and high MCV with normal MCHC

20
Q

microcytic anaemia

A

megaloblastic: low reticulocyte count

  • vitamin B12/folic acid deficiency
  • drug related

nonmegaloblastic:

  • alcoholism
  • hypothyroidism
  • liver disease
  • myelodysplastic syndromes
  • reticulocyotis
21
Q

vitramin B12 = cobalamin and folic acid

A

both important for final maturation of RBC and synthesis of DNA

both needed for thymidine triphosphate synthesis

22
Q

megaloblastic vs non megaloblastic

A

megaloblastic changes of blood cells are seen in B12 and folic acid deficiency

characterised on peripheral smear by macroovalocytes and hyperhsegmented neutrophils

23
Q

describe folate deficiency

A

folate necessary for DNA synthesis

adenosine, guanine and thymidine synthesis

24
Q

causes of folate deficiency

A 
pregnancy/breast feeding 
infancy and growth spurt 
haemolysis 
disseminated cancer 
urinary losses: heart failure

poor diet
elderly
chronic alcohol intake

medication
coeliac
jejunal resection
tropical sprue

25
Q

describe vitamin B12

A

essentail co factor for methylation in DNA and cell metabolism

intracellular conversion to 2 active coenzymes necessary for homeostasis of methylmalonic acid and homocysteine

26
Q

vitamin B12 p2

A

foods containing vit b12: fish, meat, dairy

UK intake recommendations are 1.5mg.day

requires presence of intrinsic factor for absorption in terminal ileum

IF made in parietal cells in stomach

transcobalamin II and transcobalamin I transport vit B12 to tissues.

27
Q

clinical consequences

A

brain = cognition, depression, psychosis

neurology = myelopathy, sensory changes, ataxia, spasticity

infertility
cardiac cardiomyopathy
tongue = glossitis, taste impairment

blood = pancytopenia

28
Q

pernicious anaemia

A

autoimmune disorder
lack of IF
B12 absorption

gastric parietal cell antibodies

IF antibodies

29
Q

treatment options

A

iron = diet, oral, parenteral iron supplementation, stopping the bleeding

folic acid = oral supplements

B12 = oral vs intramuscular treatment

Mechanisms of disease (29 decks)

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