Haematology 6: Iron Deficiency and Anaemia of Chronic Disease Flashcards
To remake RBC cells on a daily basis you need ___mg iron/day
- 20mg iron/day
How does the gut cell alter iron absorption?
High iron –> High hepcidin –> Low ferroportin –> Low absorption
- If hepcindin = high
- it will block the ferroportin –> stops you from absorbing as much iron
BUT - If Iron level + hepcidin = low
- ferroportin = less inhibited
- so can transport more iron –> into blood
What is Hepcidin?
Hepcidin = master controller of iron homeostasis
Where is ferroportin found?
- enterocytes of duodenum
- macrophages of spleen
- hepatocytes
List factors that will increase iron absorption
- Iron deficiency
- Anaemia / Hypoxia
- Pregnancy
How is the level of hepcidin affected?
- hepcidin = has iron responsive elements within their gene
- SO Iron = part of the complex that switches on hepcidin transcription
What are the different forms of iron ?
elemental iron –> ferritin micelles –> (+transferrin) –> transported around body
What is transferrin? What does it do?
- Transferrin holds onto iron in the circulation
Note:
- Transferrin = normally 20-40% saturated with iron
If you are hypoxic, erythropoietin secretion (increases/decreases) and RBC precursors (increases/decreases)
If you are hypoxic, erythropoietin secretion (increases) and RBC precursors (increases)
What is anaemia of chronic disease? (ACD)
- anaemia that is seen in patients with chronic disease e.g chronic infection, chronic inflammation, malignancy, cardiac failure
Patient will:
- NOT be bleeding
- NOT have any bone marrow infiltration
- NOT iron/B12/folate deficient
–> so there is no obvious cause for their anaemia except that the patient is ill
What are laboratory signs of being ill?
- C reactive protein
- Erythrocyte sedimentation Rate (ESR)
- Acute phase response –> leads to increase in
- ferritin
- factor 8
- fibrinogen
- immunoglobulins
If C reactive protein = raised + patient is anaemia –>
what would you suspect
suspect ACD
What does increase in C reactive protein suggest?
- increase = infection/ inflammation
What does increase in ESR suggest?
- increase = infection/ inflammation
List some conditions associated with ACD
- Chronic infections (TB/HIV)
- Chronic inflammation (rheumatoid arthritis)
- Malignancy
- Cardiac failure
Describe the pathogenesis of ACD
- ACD = due to cytokine (e.g TNF alpha, interleukins)
- cytokines prevent usual iron flow from duodenum –> to RBC
- blocks iron utilization by RBC
Cytokines:
- stops increases in erythropoietin
- Increases ferritin production
- increases RBC death
- -> Contributes to anaemia
- since you have fewer RBC –> less iron availability
List some causes of iron deficiency
- Bleeding (menstrual/GI tract)
- Increased use (growth/pregnancy)
- Dietary deficiency (vegetarian)
- Malabsorption (Coeliac disease)
Under what conditions is a full GI investigation performed?
- male
- female 40+
- post menstrual women
- women w scanty menstrual loss
if nothing –> small bowel mean + follow
What is meant by full GI investigation ?
- upper GI endoscopy
- duodenal biopsy
- colonoscopy
What are 3 causes of low MCV?
- iron deficiency
- thalassemia trait
- anaemia of chronic disease
for thalessaemia, would serum iron be low or normal?
Normal serum iron - for thalessaemia
for anaemia of chronic disease, would serum iron be low or normal?
Low serum iron
What are the 2 lab clues that show that ferritin is not ideal?
- raised CRP
2. raised ESR
effect on transferrin:
a) Iron Deficiency
b) ACD
effect on transferrin
a) Iron deficiency = INCREASES transferrin
b) ACD = Normal/ Low transferrin
