Iron Deficiency and Anaemia of Chronic Disease Flashcards
In what state is the iron in the haem group of haemoglobin?
Fe2+ (ferrous)
How much iron do you need per day to maintain the production of red blood cells?
20 mg/day
(but we can recycle iron)
so Men need 1mg/day and Women 2mg/day
How can iron be lost under normal, non-pathological conditions?
Desquamation of cells in the skin and gut
Bleeding (menstruation is one of the largest causes of loss of iron from the body in women)
How much iron does the human diet normally provide?
12-15 mg/day
State some natural foods that are high in iron.
Meat and fish
Vegetables
Whole grain cereal
Chocolate
Which form of iron cannot be absorbed?
Fe3+ (ferric)
What effect does drinking tea have on iron absorption?
Cups of tea promotes the conversion of Fe2+ to Fe3+ leads to chronic low levels of Ferrous
Why do meat and fish eaters have an advantage over vegetarians in terms of iron absorption?
They will absorb iron in the haem form
State three systemic factors that increase iron absorption.
Iron deficiency
Anaemia/hypoxia
Pregnancy
Which channel, on the basement membrane of intestinal epithelial cells, allows movement of iron into the circulation (blood)?
Ferroportin (transmembrane protein)
What is a key regulator of iron absorption that affects ferroportin?
Hepcidin
How is the level of hepcidin affected?
Hepcidin has iron-responsive elements in their genes
So iron is part of the complex that switches on hepcidin transcription
Where is most iron stored in the body and in which form?
As ferritin micelles in the liver
What transports iron within the circulation?
Transferrin
State three parameters that can be measured that involve transferrin?
Transferrin levels
Transferrin Saturation
Total Iron Binding Capacity (TIBC)
What is the normal transferrin saturation with iron?
20-40%
Where is erythropoietin produced, what stimulates this and what effect does it have?
Kidneys (stimulated by hypoxia)
Increase in red blood cell precursors
Red blood cell precursors will survive longer and the EPO will make them grow and differentiate to produce more progeny
What is anaemia of chronic disease?
Anaemia that is seen in patients with chronic disease
do NOT show typical causes of anaemia
What typical signs of anaemia will these patients NOT have?
They will NOT be bleeding
They will NOT be iron deficient, B12 deficient or folate deficient
They will NOT have any bone marrow infiltration
State some laboratory signs of being ill.
- Raised C-reactive protein (CRP)
- Raised Erythrocyte Sedimentation Rate (ESR)
- Acute phase response:
raised Ferritin
raised Factor VIII
raised Fibrinogen
raised Immunoglobulins
State some conditions associated with anaemia of chronic disease.
Chronic infections – e.g. TB/HIV
Chronic inflammation – e.g. SLE, rheumatoid arthritis
Malignancy
Miscellaneous (e.g. cardiac failure)
What is the pathogenesis of ACD?
ACD is due to the cytokine release that happens when someone is unwell.
Cytokines:
- Block utilisation of iron by red blood cells by preventing usual flow of iron from duodenum to red cells
- Stop erythropoietin from increasing
- Stop iron flowing out of cells
- Increase production of ferritin
- Increased death of red cells
Give examples of cytokines involved in ACD.
TNF-
Interleukins
State four broad causes of iron deficiency.
MAJOR 1. Bleeding MINOR 2. Increased use (e.g. growth, pregnancy) 3. Dietary deficiency (e.g. vegetarian) 4. Malabsorption (e.g. Coeliac disease)
