Severity of Myasthenia Gravis Influences the Relationship between Train-of-four Ratio and Twitch Tension and Run-down of Rat Endplate Potentials

Successful Neuromuscular Blockade Reversal Using Sugammadex and Neostigmine Failed to Prevent Myasthenic Crisis After Emergency Surgery: A Case Report

Recent literature suggests that the use of sugammadex for the reversal of neuromuscular blocking agents (NMBAs) reduces the risk of postoperative myasthenic crisis (MC) in patients with myasthenia gravis (MG), particularly after thymectomy, but studies are lacking on emergency surgeries. We achieved successful intraoperative reversal of neuromuscular blockade (NMB) using a combination of sugammadex and neostigmine (with glycopyrrolate). However, MC was not avoided and reintubation was required on postoperative day 1.

A 65-year-old male with a longstanding history of MG presented to the emergency department with complaints of abdominal pain, diarrhea, vomiting, chills, and fatigue for three days. A computed tomography (CT) scan of the abdomen showed acute appendicitis, for which he underwent a laparoscopic appendectomy on hospital day 1. The patient received successful general anesthesia with a rapid sequence induction using a smaller than average dose of rocuronium, given his history of MG. At the conclusion of the case, sugammadex followed by neostigmine/glycopyrrolate and a subsequent dose of sugammadex were given, with reversal of NMB. The patient was successfully extubated but required reintubation on postoperative day 1 for hypercapnic respiratory failure.

Our case report on this patient with MG yields two topics that have not been extensively examined. First, dual therapy with sugammadex and neostigmine/glycopyrrolate may provide significant clinical benefit over individual therapy for NMBA reversal, given that their mechanisms of action are different and particularly when sugammadex is given prior to neostigmine/glycopyrrolate. Second, anesthesia literature is lacking on MG patients undergoing emergency surgeries. While sugammadex has been promising in medically optimized non-emergent surgeries, we discuss here a case where sugammadex failed to prevent MC in the emergency surgery setting and a look into what may provide patients with the best chance for avoiding postoperative MC.

Post-synaptic specialization of the neuromuscular junction: junctional folds formation, function, and disorders

Post-synaptic specialization is critical to the neurotransmitter release and action potential conduction. The neuromuscular junctions (NMJs) are the synapses between the motor neurons and muscle cells and have a more specialized post-synaptic membrane than synapses in the central nervous system (CNS). The sarcolemma within NMJ folded to form some invagination portions called junctional folds (JFs), and they have important roles in maintaining the post-synaptic membrane structure. The NMJ formation and the acetylcholine receptor (AChR) clustering signal pathway have been extensively studied and reviewed. Although it has been suggested that JFs are related to maintaining the safety factor of neurotransmitter release, the formation mechanism and function of JFs are still unclear. This review will focus on the JFs about evolution, formation, function, and disorders. Anticipate understanding of where they are coming from and where we will study in the future.