Prolonged Neuromuscular Blockade Following Succinylcholine Administration and the Clinical Importance of Family History: A Case Report.

When evaluating the etiology of delayed emergence from anesthesia, several differential diagnoses must be considered, with family history often being an overlooked factor. This case report highlights the clinical significance and diagnostic challenges of one such differential - pseudocholinesterase deficiency (PD). PD is a known defect in the pseudocholinesterase enzyme that may be either inherited or acquired. This deficiency impairs the metabolism of certain pharmacologic agents, including succinylcholine, a short-acting depolarizing neuromuscular blocking agent widely used in operating rooms to facilitate endotracheal intubation. As a result, affected individuals experience prolonged neuromuscular blockade, with recovery times varying significantly and initial diagnosis often proving difficult. Although not uncommon, PD is insidious, and most individuals with this deficiency remain undiagnosed until they or a family member experience prolonged emergence from anesthesia. Laboratory tests such as the dibucaine inhibition test can quantify the deficiency, as demonstrated in this case. This report describes a 90-year-old female who was found to have heterozygous atypical PD after experiencing significantly delayed recovery - lasting eight hours - following succinylcholine administration during hip arthroplasty in the lateral position. The diagnosis was made clinically through the process of elimination and later confirmed by the dibucaine inhibition test. Postoperatively, it was revealed that several of the patient's family members had previously experienced delayed emergence from anesthesia, suggesting an inherited form of PD that was previously unknown to the patient. This case underscores the importance of considering PD in the differential diagnosis of prolonged emergence from anesthesia, highlights the value of a thorough family history, and emphasizes the need for greater awareness among clinicians to prevent life-threatening adverse events.