Perioperative iron deficiency anaemia

Question 1

Causes of Iron Deficiency Anaemia

Answer 1

• Nutritional deficiency
• Cancer and anaemia of inflammation
• Surgical blood loss
• Reduced absorption: Bariatric surgery, coeliac disease, gastritis, drugs
• Reduced intake: eating disorders, vegetarians
• Increased requirements: infants, athletes, pregnancy, blood donors
• Chronic blood loss: GI tumours, abnormal uterine bleeding, hookworm infestation

Question 2

How does hepcidin influence iron homeostasis

Answer 2

• Produced in the liver
• Hepcidin degrades ferroportin (the Fe channel) found in macrophages and duodenal enterocytes blocking GI absorption
• Hepcidin increases in inflammatory states (IL6) and high levels of transferrin-bound iron
• Hepcidin decreases in iron deficiency anaemia, hypoxia, during blood loss and increased EPO

Question 3

Expected findings in iron studies in iron deficient anaemia

Answer 3

• Hb <130
• Ferritin <30
• Tsat <20%
• If CRP >5 then consider anaemia due to inflammation

Question 4

Pre-operative anaemia is associated with the following risks…

Answer 4

• Needing a blood transfusion
• Death
• Unplanned ICU admission
• Delayed discharge
• Issues with mobilisation
• Wound infections

Question 5

Treatments for iron deficiency anaemia and pros/cons

Answer 5

Oral Iron
Pros: Cheap
Cons: Poorly tolerated, if hepcidin is high likely to be ineffective

IV Iron
Pros: Works even if hepcidin high, 50% response in 3/7, max response at 4/52
Cons: hypophosphataemia, extravasation injury, ?? infection risk if circulating iron high, anaphylaxis

EPO
Pros: Effective, quick, good for Jehovah’s witness etc
Cons: Risk of VTE, expensive

Blood Transfusion
Pros: Effective
Cons: All the risks of allogenic transfusion