Iron deficiency Anaemia Flashcards
What some iron containing proteins in humans?
Haemoglobin (main one -also acts as resevoir) Ribonucleotide reductase Cyclo-oxygenase Myoglobin Succinate dehydrogenase Cytochrome a,b,c Cytochrome p450 enzymes
How much iron do you need to maintain the production of red blood cells?
20mg/day (human diet usually provides 12-15 mg/day)
In reality most iron is recycled by body and only 1mg dietary daily needed for men, 2mg for women (lose more iron due to menstruation)
In what state is the iron in the haem group of haemoglobin?
Fe2+ (ferrous), body CANNOT absorb Fe3+ for haem
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)
State some natural foods that are high in iron.
Meat and fish
Vegetables
Whole grain cereal
Chocolate
(Iron in meat and fish more readily absorbed as already associated in haem)
What effect does drinking tea or orange juice have on iron absorption?
Cups of tea promotes the conversion of Fe2+ to Fe3+
Orange juice promotes conversion of Fe3+ to Fe2+
State other factors that increase iron absorption.
Iron deficiency Anaemia/hypoxia Pregnancy Duodenum pH Lingands associated with Fe
Which channel, on the basement membrane of intestinal epithelial cells, allows movement of iron into the circulation?
Ferroportin
What is a key regulator of iron absorption that affects ferroportin?
Hepcidin
How does ferroportin hepcidin regulation occur?
Hepcidin has iron-responsive elements in genes
Iron part of complex that switches on hepcidin transcription (produced in liver)
hepcidin degrades ferroportin so less iron enters cellss
How is iron stored within cells?
In ferritin micelles
What transports iron in the circulation?
Transferrin
State three parameters that can be measured that involve transferrin?
Transferrin
Transferrin Saturation (normally around 40%)
Total Iron Binding Capacity (TIBC)
Where is erythropoietin produced 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 but without obvious:
Bleeding
Marrow infiltration
B12, Iron or Folate deficiency
State some causes of anaemia of chronic disease.
Chronic infections – e.g. TB/HIV Chronic inflammation – e.g. SLE, rheumatoid arthritis Malignancy Miscellaneous (e.g. cardiac failure)
State some laboratory signs of being ill.
Raised C-reactive protein (CRP) Raised Erythrocyte Sedimentation Rate (ESR) Raised Ferritin Raised Factor VIII Raised Fibrinogen Raised Immunoglobulins
What is the underlying cause of ACD?
ACD is due to the cytokine (E.G TNF-a, ILs) release that happens when someone is unwell
The cytokines block utilisation of iron by red blood cells They also stop erythropoietin from increasing
Stop iron flowing out of cells Increase production of ferritin Increased death of red cells
State four broad causes of iron deficiency.
Bleeding
Increased use (e.g. growth, pregnancy)
Dietary deficiency (e.g. vegetarian)
Malabsorption (e.g. Coeliac disease)
Under what conditions are full GI investigations performed?
Male
Women over 40
Post-menopausal women
Women with scanty menstrual loss
Followed by small bowel meal and imaging
State some other investigations that can be performed.
Antibodies for coeliac disease
Check for urinary blood loss
(Menstruation tests where applicable)
What would be found in the lab to aid diagnosis of someone with iron deficient anaemic symptoms?
MCV
Serum iron
Ferritin
Transferrin = TIBC (total iron binding capacity) Transferrin saturation
State three causes of a low MCV.
Iron deficiency
Anaemia of chronic disease
Thalassemia trait
How would you confirm thalassemia trait?
Haemoglobin electrophoresis
How does serum iron help distinguish between the three causes of microcytic anaemia?
Iron deficiency – LOW serum iron
ACD – LOW serum iron
Beta thalassaemia - NORMAL serum iron
Describe the difference in ferritin levels in iron deficiency and anaemia of chronic disease.
Iron deficiency – LOW
ACD – HIGH (because it is an acute phase protein)
Why is ferritin not always reliable?
Some people may have a chronic disease and be bleeding e.g. rheumatoid arthritis and a bleeding ulcer In this case the ferritin may appear normal
You need to check the signs of infection/inflammation such as ESR and CRP to see if there is an underlying condition causing a rise in acute phase proteins
Describe the difference in transferrin in iron deficiency and ACD.
Iron deficiency – HIGH
ACD – LOW/NORMAL
Describe the difference in transferrin saturation in iron deficiency and ACD.
Iron deficiency – LOW
ACD – NORMAL
What is the diagnosis of a man of any age with a low ferritin?
Iron deficiency
He needs upper and lower GI endoscopies to look for the source of the bleeding
State what you’d expect the following parameters to be in iron deficiency: a. Hb b. MCV c. Serum Iron d. Ferritin e. Transferrin f. Transferrin Saturation
Hb - LOW MCV - LOW Serum Iron - LOW Ferritin - LOW Transferrin - HIGH Transferrin Saturation - LOW
State what you’d expect the following parameters to be in anaemia of chronic disease: a. Hb b. MCV c. Serum Iron d. Ferritin e. Transferrin f. Transferrin Saturation
Hb - LOW MCV - LOW/NORMAL Serum Iron - LOW Ferritin - HIGH/NORMAL Transferrin - LOW/NORMAL Transferrin Saturation - NORMAL
State what you’d expect the following parameters to be in thalassemia trait: a. Hb b. MCV c. Serum Iron d. Ferritin e. Transferrin f. Transferrin Saturation
Hb - LOW MCV - LOW Serum Iron - NORMAL Ferritin - NORMAL Transferrin - NORMAL Transferrin Saturation - NORMAL
