High incidence of adverse reactions to locoregional anaesthesia containing hyaluronidase after uneventful ophthalmic surgery

Allergic Complications of Hyaluronidase Injection: Risk Factors, Treatment Strategies, and Recommendations for Management

BACKGROUND

Hyaluronidase is used as a reversal agent for hyaluronic acid fillers and to increase the diffusion of other medications after infiltration. Cases of hyaluronidase allergy have been described in the literature since 1984. However, it is still frequently misdiagnosed. This review aims to summarize the current literature to describe the clinical picture of hyaluronidase allergy and identify any risk factors associated with its development, as well as provide recommendations for management in plastic surgery.

METHODS

A digital search of PubMed, Scopus, and Embase databases was performed by two reviewers following the PRISMA guidelines. This search identified 247 articles.

RESULTS

Two hundred forty-seven articles were identified, and 37 of them met the eligibility criteria. One hundred six patients with a mean age of 54.2 years were included in these studies. History of allergy to other substances (timothy grass, egg white, horse serum, penicillin, insect bites, wasp venom, thimerosal, potassium, histamine, phenylmercuric acetate, and nickel) and allergic diseases (asthma, dermatitis, atopy, rhinitis) was reported. A large portion of the patients with a history of repeated exposure (2-4) experienced the symptoms with their second injection. Nonetheless, there was no significant association between time to allergy development and the number of exposures (P = 0.3). Treatment with steroids +/- antihistamines resulted in the rapid and predominantly complete reversal of the symptoms.

CONCLUSIONS

Prior injections or sensitization by insect/wasp venom might be the primary factor associated with hyaluronidase allergy development. The time between the repeated injections is not a likely contributor to the presentation.

LEVEL OF EVIDENCE III

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Clinical Applications of Hyaluronidase

Hyaluronidases are enzymes that degrade hyaluronic acid, which constitutes an essential part of the extracellular matrix. Initially discovered in bacteria, hyaluronidases are known to be widely distributed in nature and have been found in many classes including insects, snakes, fish and mammals. In the human, six different hyaluronidases, HYAL1-4, HYAL-P1 and PH-20, have been identified. PH-20 exerts the strongest biologic activity, is found in high concentrations in the testicles and can be localized on the head and the acrosome of human spermatozoa. Today, animal-derived bovine or ovine testicular hyaluronidases as well as synthetic hyaluronidases are clinically applied as adjuncts to increase the bioavailability of drugs, for the therapy of extravasations, or for the management of complications associated with the aesthetic injection of hyaluronic acid-based fillers. Further applications in the fields of surgery, aesthetic medicine, immunology, oncology, and many others can be expected for years to come. Here, we give an overview over the molecular and cellular mode of action of hyaluronidase and the hyaluronic acid metabolism, as well as over current and potential future clinical applications of hyaluronidase.

Ophthalmic regional blocks: management, challenges, and solutions

In the past decade ophthalmic anesthesia has witnessed a major transformation. The sun has set on the landscape of ophthalmic procedures performed under general anesthesia at in-hospital settings. In its place a new dawn has ushered in the panorama of eye surgeries conducted under regional and topical anesthesia at specialty eye care centers. The impact of the burgeoning geriatric population is that an increasing number of elderly patients will present for eye surgery. In order to accommodate increased patient volumes and simultaneously satisfy administrative initiatives directed at economic frugality, administrators will seek assistance from anesthesia providers in adopting measures that enhance operating room efficiency. The performance of eye blocks in a holding suite meets many of these objectives. Unfortunately, most practicing anesthesiologists resist performing ophthalmic regional blocks because they lack formal training. In future, anesthesiologists will need to block eyes and manage common medical conditions because economic pressures will eliminate routine preoperative testing. This review addresses a variety of topical issues in ophthalmic anesthesia with special emphasis on cannula and needle-based blocks and the new-generation antithrombotic agents. In a constantly evolving arena, the sub-Tenon's block has gained popularity while the deep angulated intraconal (retrobulbar) block has been largely superseded by the shallower extraconal (peribulbar) approach. Improvements in surgical technique have also impacted anesthetic practice. For example, phacoemulsification techniques facilitate the conduct of cataract surgery under topical anesthesia, and suture-free vitrectomy ports may cause venous air embolism during air/fluid exchange. Hyaluronidase is a useful adjuvant because it promotes local anesthetic diffusion and hastens block onset time but it is allergenic. Ultrasound-guided eye blocks afford real-time visualization of needle position and local anesthetic spread. An advantage of sonic guidance is that it may eliminate the hazard of globe perforation by identifying abnormal anatomy, such as staphyloma.