Question 26.2

Last updated 22/06/2023 - 17:17
 Topic: Haematology and Oncology
Pass rate
80.8%
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The following data refer to a patient admitted electively to ICU following extensive pelvic surgery for invasive endometrial carcinoma. The patient has remained in ICU for 22 days because of complications including acute kidney injury.

Parameter

Patient Value

Adult Normal Range

Haemoglobin

66 g/L*

125 – 180

Serum ferritin

14 µg/L*

15 – 300

Serum iron

3 µmol/L*

9 – 27

Total Iron Binding Capacity (TIBC)

86 µmol/L*

47 – 70

Transferrin Saturation

(Iron / TIBC x 100)

9%*

16 – 40

Erythropoietin level

41 U/L*

4 – 28

C-reactive protein (CRP)

60 mg/L*

< 8

a)    State the abnormality demonstrated in this patient? Give your reasoning.    (20% marks)

b)    List two potential causative factors in this patient.    (10% marks)
 
c)    Briefly outline the available treatment options to correct the demonstrated abnormality including any disadvantages/risks.    (20% marks)
 

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College answer

Very well answered, with most candidates demonstrating the ability to interpret and discuss anaemia. Many candidates omitted EPO and conservative treatment for iron-deficiency anaemia in the management part of the question. Poorer answers did not identify the cause of anaemia correctly.

Discussion

a)

So, this patient has

  • Anaemia
  • Low serum ferritin, suggesting poor iron stores
  • Low serum iron
  • Raised TIBC and low transferrin saturation, suggesting if there was iron around, there'd be plenty of proteins available to carry it
  • A raised erythropoietin level (which is actually normal, because this is a completely appropriate reaction to anaemia)

So: this is a classical picture seen with anaemia of iron deficiency.

b)

Why would this patient have iron deficiency?

Well:

  • Endometrial carcinoma tends to present with PV blood loss, so there would have been pre-operative iron loss already
  • The surgery itself is described as "extensive", meaning might have been some kind of horrific bloodbath, or possibly complicated by mishaps (eg. the surgical notes meticulously document the repair of a common iliac artery)
  • The long ICU stay suggests further surgical problems (perhaps related to blood loss?)
  • Long ICU stay tends to be associated with frequent blood sampling, which is an iatrogenic source of blood loss
  • The acute kidney injury may have resulted in poor EPO secretion, except they gave us the EPO level and it is actually appropriately elevated, which raises the question: why did they mention the acute kidney injury in the stem? Nothing is accidental. Most likely somebody complained that the stem was without meat.
  • A reader (thanks Vinay!) has pointed out that malnutrition and hepcidin-upregulation-related poor gut absorption of iron could also be responsible for the anaemia

c)

The management options include:

  • Red cell transfusion (obviously)
    • Risks of transfusion reaction and circulatory overload
  • Iron infusion 
    • Anaphylaxis is a potential risk
  • Iron supplementation
    • Risks is in the constipation they cause, as well as the inherent slowness of correction
  • Minimisation of losses (rationalised blood sampling, use of paediatric tubes)
    • Risk is the possibility that decreased sampling will miss abnormalities

References

Hawkins, Stephen F., and Quentin A. Hill. "Diagnostic Approach to Anaemia in Critical Care." Haematology in Critical Care: A Practical Handbook (2014): 1-8.

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