Iron Def Anaemia Flashcards
What are the subdivisions of anaemia?
- Microcytic,
- Normocytic,
- Macrocytic
What are some causes of microcytic anaemia?
TAILS:
Thalassaemia,
Anaemia of chronic disease,
Iron def anaemia
Lead posioning
Sideroblastic anaemia
What are some causes of normocytic anaemia?
2 A’s and 2 H’s:
Acute blood loss,
Anaemia of chronic disease
Aplastic anaemia
Haemolyic anaemia
Hypothyroidism
Explain how iron is transferred to erythrocytes (RBCs)
Transferrin will bind to transferrin receptors on the surfaces of erythrocytes. The erythrocytes take up the iron and either send it to the mitochondria where it will produce haem of store the iron as ferritin.
What is the reticuloendothelial system and how does it store iron?
RES - comprised of cells decending from monocytes that are able to phagocytose materials.
Macrophages phagocytose old red blood cells (around their 120 day life span), Hemosiderin then stores the ferritin in the macrophages.
1mmol/l of serum ferritin = how much RES iron and what is the issue with using this as a method of measuring RES iron?
8mg of RES iron. However, Serum ferritin is an acute phase protein so will appear raised in time of inflammation or tissue damage
Explain the absorption of iron
Mainly occurring in the duodenum, iron crosses the cell membrane via the DMT1 channel into the enterocyte. It can then cross into the plasma via the ferroporin channel (regulated by hepcidin)
What is the daily iron intake needs?
1-2mg per day
What prevents the absorption of iron?
Hepcidin. It binds to ferroportin and degrades it, reducing iron absorption and decreasing iron release from RES. This is the only way of regulating iron in the body as there is no method of excretion
What is the molecular basis of hereditary haemochromatosis?
Loss of hepcidin so cannot prevent absorption of iron
Describe the development of IDA
Initially, Hb will remain normal despite low serum ferritin and low RES iron stores. This is called latent iron deficiency. Overtime this will progress and Hb will fall. Therefore IDA is gradual
What are the causes of iron def anaemia?
- Excessive blood loss: Menorrhagia in young women. GI bleeding in men and post-menopausal women (always suspect colon cancer)
- Inadequate dietary intake (vegans and veggies)
- Poor intestinal absorption (coeliac’s)
- Increased iron requirements (pregnancy)
What are the symptoms of iron deficiency anaemia
Palor, tachycardia, rapid breathing, peripheral oedema (if severe),
Koilonychia, hair loss, pica, atrophic glossitis, angular stomatitis, oesophageal web
What is an oesophageal web?
A thin mucous membrane that forms across the upper part of the oesophagus which causes dysphagia.
What are the investigations for iron def anaemia?
- History (ask about diet, menstruation, meds, weight loss, bowel habit)
- FBC - Hypochromic microcytic anaemia,
- Serum ferritin - Low (be careful as it is an acute phase reactant)
- Total iron-binding capacity/transferrin - High TIBC and low transferrin saturation.
- Blood film
- Endoscopy (post menopausal women with Hb < 10 and men with Hb < 11 should ger 2 week wait referral)
