Hyaluronidase toxicity: a possible cause of postoperative periorbital inflammation

Background: Periorbital inflammation following regional anaesthesia is commonly attributed to hyaluronidase allergy. This case series suggests an alternative explanation in some patients. Design: Retrospective case series. Participants: Seven patients presenting with postoperative non-infectious periorbital inflammation following peribulbar or sub-tenons anaesthesia, presenting at four different institutions, are described. Methods: Data on patient demographics, operative data, clinical presentation, treatment and allergy testing were collected among the four institutions. Main Outcome Measures: Response to treatment and allergy testing were noted among the patients included in this study. Results: Seven patients (five female) underwent uneventful phacoemulsification under a peribulbar or sub-tenon's block, all including hyaluronidase with concentrations ranging 50250IU/mL. The onset of inflammatory symptoms and signs varied from 12h to 3days after the surgery. The most common form of presentation was lid swelling and chemosis. Patients were treated with oral corticosteroids, with good clinical response. Four patients underwent skin prick and intradermal testing to the local anaesthetic used, and to the suspect and a control hyaluronidase batch. The results were all negative, excluding allergy as the aetiology of this toxic periorbital syndrome, in at least these four patients. Conclusion: Hyaluronidase toxicity, potentially related to concentration of hyaluronidase, may be a cause of postoperative periorbital inflammation after cataract surgery, rather than hypersensitivity.