nutritional anemias Flashcards
what is anaemia
condition which number of RBC is insufficient to meet bodies physiologic needs
what is haemoglobin
iron containing oxygen transport metalloprotein within RBCs
normal erythropoiesis
maturation of RBC require:
- vitaminB12 and folic acid, DNA synthesis, iron and haemoglobin synthesis
vitamins
cytokines
healthy bone marrow environment
anaemia: mechanisms of action
failure of production = hypo proliferation reticulocytopenic
ineffective erythropoesis
decreased survival = blood loss, haemolysis, reticulocytosis
describe microcytic
iron deficiency
thalassamia
anaemia of chronic disease
describe normocytic
anemia chronic disease
aplastic anaemia
chronic renal failure
bone marrow infiltration
sickle cell disease
describe macrocytic
B12 deficiency
folate deficiency
myelodysplasia
alcohol induced
drug induced
liver disease
myxoedema
nutritional anemias
anaemia caused by lack of essential ingredients that the body acquires from food sources
iron deficiency
vitamin B12 deficiency
folate deficiency
describe iron
essential for O2 transport
most abundant trace element in body
daily requirement for iron for erythropoiesis varies depending on gender and physiological needs
describe the distribution of iron in adults
- plasma transferrin
utilisation = muscle myoglobin or bone marrow
or storage iron in liver
reticuloendothelial macrophages
sloughed mucosal cells
desquamination/menstruation
iron metabolism
> 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
describe iron absorption
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
iron regulation: hepcidin
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
iron transport and storage
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
iron deficiency in anaemia lab results
ferritin = low
tf saturation = low
TIBC = high
serum iron = low/normal
causes of iron deficiency
not enough in:
- poor diet
- malabsorption
- increased physiological needs
losing too much:
- blood loss
- menstruation, GI tract loss, parasites
most common cause of IDA in women and men
blood loss from GI tract for men and postmenopausal women
symptoms of anaemia
fatigue
lethargy
dizziness
pallor of mucous membranes bouding pulse systolic flow murmurs smooth tongue kolionychias
b12 and folate deficiency
both have similar lab findings and clinical symptoms
found together or as isolated pathologies
macrocytic anaemia:
- low Hb and high MCV with normal MCHC
microcytic anaemia
megaloblastic: low reticulocyte count
- vitamin B12/folic acid deficiency
- drug related
nonmegaloblastic:
- alcoholism
- hypothyroidism
- liver disease
- myelodysplastic syndromes
- reticulocyotis
vitramin B12 = cobalamin and folic acid
both important for final maturation of RBC and synthesis of DNA
both needed for thymidine triphosphate synthesis
megaloblastic vs non megaloblastic
megaloblastic changes of blood cells are seen in B12 and folic acid deficiency
characterised on peripheral smear by macroovalocytes and hyperhsegmented neutrophils
describe folate deficiency
folate necessary for DNA synthesis
adenosine, guanine and thymidine synthesis
causes of folate deficiency
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
describe vitamin B12
essentail co factor for methylation in DNA and cell metabolism
intracellular conversion to 2 active coenzymes necessary for homeostasis of methylmalonic acid and homocysteine
vitamin B12 p2
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.
clinical consequences
brain = cognition, depression, psychosis
neurology = myelopathy, sensory changes, ataxia, spasticity
infertility
cardiac cardiomyopathy
tongue = glossitis, taste impairment
blood = pancytopenia
pernicious anaemia
autoimmune disorder
lack of IF
B12 absorption
gastric parietal cell antibodies
IF antibodies
treatment options
iron = diet, oral, parenteral iron supplementation, stopping the bleeding
folic acid = oral supplements
B12 = oral vs intramuscular treatment
