Iron overload

When to suspect this adverse reaction?

Patients who are chronically dependent on red cell transfusions (eg thalassaemia, red cell aplasia) will accumulate excess total body iron over time. Excessive iron is accumulated in certain organs such as the liver, heart and endocrine organs and affect their function.

Early symptoms are often vague such as muscle weakness, fatigue and weight loss. Later skin pigmentation, arthropathy, diabetes, impotence, cardiac failure and hepatic dysfunction can occur.(1,2)

 

Usual causes?

Each unit of red cells contains about 250 mg of iron and the average rate of iron excretion is only about 1 mg/day.  Therefore, iron overload can occur after transfusion of about 10 to 20 units of red cell.(1)

 

Investigation

Severity of iron overload can be determined by measuring serum ferritin, MRI which assesses iron concentration in the heart and liver and occasionally by liver biopsy.(3)

 

What to do?

Treatment is aimed at removal of accumulated iron in the tissues by using iron chelating agents which form a complex with iron and promotes its excretion.(1,4)
 

References
  1. Fung, MK, Grossman BJ, Hillyer CD, Westhoff CM (ed).  Non-infectious complications of blood transfusion.  Chapter 27, AABB Technical Manual, 18th editon.  AABB, Besthesda, 2014.
  2. Harmening DM (ed). Chapter 18, Adverse Effects of Blood Transfusion. Modern Blood Banking and Transfusion Practices, 5th edition. FA Davis Company, Philadelphia, 2005.
  3. Fleming RE and Ponha P.  Iron overload in human disease.  N Engl J Med 2012 Jan 26;366:348-359.
  4. Brittenham GM. Iron-chelating therapy for transfusional iron overload. New England Journal of Medicine 2011 Jan 13;364(2):146–156.