Perianesthetic Implications and Considerations for Myasthenia Gravis

Anesthetic considerations for a patient with myasthenia gravis undergoing deep sedation in an outpatient oral surgery setting

“…The amount of anticholinesterase administered pre-operatively is a function of the necessity and dosage required of muscle relaxants for the particular procedure, with dosages possibly being withheld or reduced [14]. Corticosteroids can either be weaned off in MG patients, or those with long-term use of steroid treatment can receive one intravenous dose prior to surgery, as acute cessation of usage can contribute to perioperative hemodynamic instability [15].…”

“…The patient should also exhibit normal cardiovascular function and present without any cardiac arrhythmias such as bradycardia or atrial fibrillation, ST and T wave abnormalities, and conductive deficits [14]. Coupling these assessments with a survey of the patient's degree of severity of MG, muscle groups involved, and their longitudinal disease management, as well as taking into account their current medications, ensures a correct and safe operative management plan is in place tailored both to the patient and the procedure being performed [15]. Post-operatively, it is important the patient exhibits unassisted ventilation with a patent airway, should be monitored for any signs of respiratory distress, and display no symptoms indicative of myasthenic or cholinergic crisis [1315].…”

“…Respiratory depression is a common side effect associated with deep sedation, and can be exacerbated in patients with MG [14]. As such, close observation of MG patients for any signs of perioperative respiratory distress that could trigger a myasthenic crisis is of paramount importance given their predisposed neuromuscular issues [1415].…”

“…Namely, non-depolarizing NMBAs have an inhibitory effect on neuromuscular transmission in MG patients and as such should be utilized with caution for procedures [913]. Low doses titrated to effect of short or intermediate-acting non-depolarizing NMBAs, such as rocuronium, are preferable to their longer-acting counterparts to help minimize the suppressive effects on neurotransmission, and is easily reversible with sugammadex [915]. Moreover, depolarizing NMBAs such as succinylcholine are met with resistance when utilized with MG patients due to the diminished presence of available AChRs, which in turn can cause adverse and prolonged neuromuscular blockade given the majority of MG patients utilize anticholinesterases as their first line treatment [15].…”

Sarcopenia and perioperative management of elderly surgical patients

“…The efficacy of non-depolarizing muscle relaxants in myasthenia gravis patients is also significantly enhanced, and one-fourth of the standard intubating dose of rocuronium can achieve a complete neuromuscular block [129,130]. In addition, the use of muscle relaxants can aggravate myasthenia gravis and cause respiratory distress [131]. The pathogenesis of sarcopenia is complicated, especially the presence of motor unit remodeling; neuromuscular junction degeneration, including a reduction in the number of acetylcholine re-ceptors; endplate fragmentation; and reduction in postsynaptic folds, which may significantly change the pharmacological properties of muscle relaxants.…”