Massive haemolysis after intramuscular diclofenac in a patient who apparently tolerated oral medication

Background and Objectives Administration of diclofenac may lead to immune haemolytic anaemia (IHA) owing to the presence of drug-dependent antibodies and/or autoantibodies. A relationship with oral or intramuscular drug administration is unknown. Here, we describe a patient who apparently tolerated oral diclofenac but developed severe IHA following intramuscular injection of the drug. Patients and Methods A 66-year-old-female was admitted to hospital because of jaundice and nausea, which were initially presumed to be manifestations of a postcholecystectomy syndrome. The patient soon developed haemolysis and renal failure. Although the symptoms and signs were suggestive of autoimmune haemolytic anaemia (AIHA), the patient had diclofenac-induced IHA. Results Serological testing, including detection of drug-dependent antibodies, was performed using standard techniques. The patient's serum was found to contain a highly reactive diclofenac-dependent red cell antibody of the immune complex type (titre 256 000). She recovered after 7 weeks of treatment with prednisolone, blood transfusions, haemodialysis and plasma exchange. Conclusions Diclofenac-induced IHA should always be considered when a patient on diclofenac develops haemolysis.