In this Clinical Case Study by J.E. Whittington et al., the authors summarize the literature regarding butyrylcholinesterase (BChE) deficiency and provide a comprehensive summary of the various phenotypes in Table 1, which illustrates the relatively low frequencies of the atypical phenotypes of BChE. Nevertheless, there are substantial clinical implications of reduced BChE activity. Patients who have a low-activity BChE phenotype may experience serious complications if this genetic predisposition is not managed appropriately. Although the authors' case illustrates the potentially serious implications of this disorder from a ventilatory perspective, the relative importance of reduced BChE activity on the pharmacokinetic and biologic activity of various other pharmacologic agents is also highlighted.
One issue not addressed in this Clinical Case Study is related to iatrogenic inhibition of this enzyme in the setting of either perioperative reversal of nondepolarizing muscle relaxant agents (e.g., neostigmine) or with the chronic management of myasthenia gravis (e.g., pyridostigmine). Although the prolonged duration of action of succinylcholine after the administration of agents like neostigmine has been extensively described, there are also a few reports of resistance to muscle relaxation with succinylcholine. One can speculate that patients with a hereditary reduction in BChE activity may display more-profound effects when these acetylcholinesterase inhibitors are administered. The clinical utility of recombinant (transgenic) BChE in these variant patients may also be of some benefit.
A better understanding of the issues outlined in this case should help clinicians confirm the diagnosis and help with the management of patients with reduced BChE when they are encountered in their clinical practice.
Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and have met the following 3 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b) drafting or revising the article for intellectual content; and (c) final approval of the published article.
Authors' Disclosures or Potential Conflicts of Interest: No authors declared any potential conflicts of interest.
- Received for publication August 22, 2011.
- Accepted for publication August 29, 2011.
- © 2012 The American Association for Clinical Chemistry