Article Text
Abstract
Aims Infusion related reactions (IRRs) in patients receiving enzyme replacement therapies (ERTs) for lysosomal storage disorders are well recognised, with mild reactions reported in 15%– 50% of patients, and severe or anaphylactic reactions in 0.2%–7.7%. Acute assessment, investigation and management practices vary. This study aimed to review practice in a tertiary centre and to optimise assessment and management pathways.
Methods A single-centre 4 year retrospective case-note review was undertaken. All patients receiving ERT were included, and the IRR incidence determined. Acute assessment, investigations and management were compared with current anaphylaxis guidelines (Resuscitation Council UK; Royal College of Paediatrics and Child Health).
Results v 105 patients receiving ERT were identified (idursulfase n=21; alglucosidase alfa n=15; laronidase n=15; elosulfase alfa n=14; velaglucerase n=14, galsulfase n=9; agalsidase alpha n=9; agalsidase beta n=4; imiglucerase n=4).
5 (4.8%) had significant (moderate or severe) IRRs (laronidase n=2, idursulfase n=1, elosulfase n=1, agalsidase beta n=1). 4 (80%) were male and the mean age at first IRR was 6.7 years (range 3.6–12.2). IRRs occurred on 5–8th infusion (n=4) and 25th infusion (n=1), and at varying rate increments. Only 60% of mandated clinical assessments were documented. 3/5 were classified as having anaphylaxis and 2/5 moderate hypersensitivity reactions.
Investigations obtained included: tryptase (performed in 5/5; all 5 normal); total IgE (performed in 3/5, 2 abnormal); anti-ERT IgG antibody (performed in 5/5, titres 800– 51 200).
Acute management included pausing infusion (5/5); additionally 2/5 received intravenous hydrocortisone only, and 3 received intramuscular adrenaline, intravenous hydrocortisone and intravenous antihistamine. 80% received treatment appropriate for the IRR severity classification.Subsequent management included addition of steroid pre-medication (5/5) and infusion rate modification (3/5). All could successfully continue treatment.
Conclusions The occurrence of severe anaphylaxis to ERT warrants in-hospital initiation of ERT. A standardised ‘Traffic Light’ ERT reaction protocol (green – mild reaction; yellow – moderate hypersensitivity; red – severe anaphylaxis ) has been developed to facilitate optimum nursing and medical assessment, investigation and management of IRRs.