nutritional anaemia Flashcards
definition of anaemia
no. of RBCs (consequently the O2 carrying capacity) is insufficient to meet the bodies physiological needs
haemoglobin
iron containing O2 transport metalloprotein within RBCs
components of blood
RBCs, platelets, WBCs
example of difference in Hb levels when diagnosing anaemia
differs in age, gender, physiological state e.g. pregnant
eythropoesis
maturation of RBC from erythropoietic stem cell
what is required for normal erythropoiesis to take place?
vitamin B12 & folic acid, DNA synthesis, Iron, Hb synthesis
3 main mechanisms of action of anaemia
- Failure of production (hypoproliferation, reticulocytopenic)
- Ineffective Erythropoiesis
- Decreased survival (haemolysis, reticulocytosis)
Reticulocytopenic
Abnormal decrease of reticulocytes in the body. Reticulocytes are new, immature red blood cells.
Reticulocytosis
Increase in reticulocytes
Haemolysis
Rupture or destruction of RBCs
Mean Cell Volume (MCV)
describes average RBC size
Microcytic
small, hypochromic RBCs
- e.g. iron deficiency, thalassaemia, anaemia of chronic disease
Normocytic
normal sized RBCs, but a low number
- e.g. anaemia of chronic disease, aplastic anaemia, chronic renal failure, bone marrow infiltrations sickle cell disease
Macrocytic
large sized RBCs
- e.g. B12/Folate deficiency, Myelodisplasia, Alcohol/Drug induced, Liver disease, Myxoedema
Nutritional Anaemia
Anaemia caused by lack of essential ingredients that the body requires, e.g. Iron, Folate & B12 deficiency
where is iron absorbed?
duodenum
what is transferrin?
Transferrins are iron-binding blood plasma glycoproteins that control the level of free iron (Fe) in biological fluids.
what is Ferritin?
storage of iron: when there is excess iron (will be low in iron deficiency)
how is iron absorption regulated?
by hepcidin, via ferroportin receptors on enterocytes
Action of hepcidin
degrades ferroportin, decreasing iron transfer from blood plasma from duodenum
causes of iron deficiency
- not enough in diet, malabsorption
- excess loss, e.g. blood loss
normochromic
normal concentration, but insufficient number of RBCs
symptoms of iron deficiency anaemia
fatigue, lethargy & laziness
signs of iron deficiency anaemia
pallor of mucous membranes, bounding pulse, systolic flow murmurs, smooth tongue, koilonchias
megaloblastic macrocytic anaemia
vitamin b12/folate deficiency: RBCs larger than normal
nonmegaloblastic macrocytic anaemia
no impairment of DNA synthesis: due to alcoholism, hypothyroidism, liver disease
source of B12
animal & dairy produce
source of folate
vegetables, liver
importance of vitamin B12 & folic acid
final maturation of RBC and DNA synthesis, for thymidine triphosphate synthesis
peripheral smear of B12 & Folic acid deficiency
macroovalocytes & hypersegmented neutrophils
folate uses
Adenosine, guanine and thymidine synthesis
vitamin B12 uses
Essential co-factor for methylation in DNA and cell metabolism
how is vitamin B12 absorbed
requires the presence of intrinsic factor for absorption in the terminal ileum
(IF is made in parietal cells in the stomach)
how is vitamin B12 transported
Transcobalamin II and Transcobalamin I transport vitB12 to tissues
clinical consequences of VitB12 & Folic acid deficiency
Brain: cognition, depression, psychosis Neurology: myelopathy, sensory changes, ataxia, spasticity (SACDC) Infertility Cardiac cardiomyopathy Tongue: glossitis, taste impairment Blood: Pancytopenia
what is pernicious anaemia?
autoimmune disoder, with a lack of IF - reduced B12 absorption
IF antibodies
treatments for anaemia
Iron – diet, oral, parenteral iron supplementatin, stopping the bleeding
Folic Acid – oral supplements
B12 – oral vs intramuscular treatment
