production v removal -> aneamia?
3 types of MCV?
Hypochromic (pale) MICROCYTIC - low MCV
microcytic anaemia?
low MCV
aetiology of microcytic anaemia?
Iron deficiency anaemia - the MOST COMMON CAUSE WORLDWIDE
• Anaemia of chronic disease
• Thalassaemia (see inherited red cell disorders)
formation of haem -> haemoglobin using iron?
Iron is required for the formation of the haem part of haemoglobin
• Iron ions are actively transported into the duodenal intestinal epithelial cells
by the intestinal haem transporter (HCP1) which is highly expressed in the
duodenum and some is incorporated into FERRITIN (protein-iron complex) that
acts as an intracellular store for iron
• Absorbed iron that does not bind to ferritin is released into the blood where it
is able to circulate around the body bound to the plasma protein
TRANSFERRIN
• Transferrin transports iron in the blood plasma to the bone marrow to be
incorporated into new erythrocytes
• The majority of iron is incorporated into haemoglobin
• The rest is stored in reticuloendothelial cells, hepatocytes and skeletal
muscle cells either as FERRITIN (majority - more easily mobilised than
haemosiderin for Hb formation, found in small amounts in plasma and in
most cells especially liver, spleen and bone marrow) or HAEMOSIDERIN
(found in macrophages in the bone marrow, liver and spleen)
epidemiology of iron deficient anaemia?
aetiology of iron deficient anaemia?
pathophysiology of iron deficient anaemia?
Less iron is available for haem synthesis - crucial for haemoglobin
production thus reduction in iron will result in a decrease in haemoglobin
and thus smaller RBC’s resulting in microcytic anaemia
clinical presentation or iron deficient anaemia?
investigation of iron deficient anaemia?
treatment of iron deficient anaemia?
anaemia of chronic diseases, what is this?
Essentially this is anaemia that is secondary to a chronic disease, can think of
it as if the body is sick then the bone marrow will be too, resulting in anaemia
• RBC’s are often NORMOCYTIC but they can be MICROCYTIC, especially in
rheumatoid arthritis and Crohn’s disease
epidemiology of anaemia of chronic disease?
- in people with chronic infections; crohns, RA, SLE and TB
pathophysiology of anaemia of chronic disease?
There is decreased release of iron from the bone marrow to developing
erythroblasts (early RBC, before reticulocyte)
- An inadequate erythropoietin response (cytokine which increases RBC
production) to anaemia
- Decreased RBC survival
clinical presentations of anaemia of chronic disease?
investigations of anaemia of chronic diseases?
treatment of anaemia of chronic causes?
Erythropoietin is effective in raising the haemoglobin level and is used in
anaemia of renal disease and inflammatory disease e.g. rheumatoid
arthritis and inflammatory bowel disease
causes of normal MCV anaemia?
investigation of normlytic anaemia?
macrolytic anaemia, sub types?
Megaloblastic:
- Presence of erythroblasts with delayed nuclear maturation because of
delayed DNA synthesis - these are megaloblasts, they are large (i.e.
high MCV) and have no nuclei
• Non-megaloblastic:
- Where the erythroblasts are normal i.e. normoblastic
main causes of macrolytic anaemia?
- non-megaloblastic; alcohol, liver disease, hypothyroidism, haemoloysis, myeloma, aplastic anaemia
B12 physiology?
B12 is absorbed by binding to INTRINSIC FACTOR produced by the
PARIETAL CELLS of the stomach then being absorbed in the TERMINAL
ILEUM of the small intestines
- B12 is essential for thymidine and thus DNA synthesis
- Thus in B12 deficiency there is an impairment of DNA synthesis resulting in
delayed nuclear maturation resulting in large RBCs as well as decreased
RBC production in the bone marrow
- This DNA impairment will affect all cells, but bone marrow is most affected
since its the most active in terms of cell division
pernicious anaemia?
AUTOIMMUNE DISORDER in which the parietal
cells of the stomach are attacked resulting in atrophic gastritis and the loss
of intrinsic factor production and thus vitamin B12 malabsorption
pernicious anaemia epidemiology?