FRCPath Haem Part 1 MCQs-Transfusion 483
A 24-year-old man with HbSS is admitted with a severe vaso-occlusive episode and acute chest syndrome. His baseline haemoglobin is 82 g/L. He receives 2 units of appropriately phenotype-matched red cells, with an initial post-transfusion haemoglobin of 81 g/L. He is discharged after clinical improvement.
Nine days later, he is readmitted with severe limb and back pain, fever and dark-coloured urine. His haemoglobin is now 58 g/L. Further investigations show:
Hb 58 g/L
Reticulocytes 1.2%
Bilirubin increased
DAT negative
No new clinically significant red-cell alloantibody detected initially
He is treated promptly with IVIg 1 g/kg and intravenous methylprednisolone 1 g daily. Twenty-four hours later, his haemoglobin has fallen further to 49 g/L, haemolysis remains marked and his renal function continues to deteriorate.
Which of the following is the most appropriate next treatment?
A. Transfuse 2 units of antigen-matched red cells
B. Rituximab
C. Eculizumab
D. Exchange transfusion
E. Increase the dose of hydroxycarbamide F. Tocilizumab
Correct answer: C. Eculizumab
Explanation
This patient has severe hyperhaemolysis syndrome (HHS), the most severe form of a delayed haemolytic transfusion reaction.
The key diagnostic clues are:
Haemoglobin falling below the pre-transfusion baseline
Evidence of haemolysis
Reticulocytopenia, which is particularly characteristic of hyperhaemolysis
Haemoglobinuria
Falling HbA following transfusion
Evidence of destruction of both transfused HbA-containing cells and the patient's endogenous HbS-containing red cells
DAT may be negative
Alloantibodies may be absent initially or appear later
Further transfusion can worsen haemolysis
The patient has already received appropriate first-line therapy with IVIg and corticosteroids. After 24 hours, he has ongoing/worsening haemolysis with symptomatic severe anaemia and organ dysfunction (acute kidney injury).
This is an indication for second-line eculizumab.
Eculizumab is a monoclonal…