Anaesthesia and neuromuscular disorders: what a neurologist needs to know

Abstract

Neurologists are often asked for specific advice regarding patients with neuromuscular disease who require general anaesthesia. However, guidelines on specific neuromuscular disorders do not usually include specific guidelines or pragmatic advice regarding (regional and/or general) anaesthesia or procedural sedation. Furthermore, the medical literature on this subject is mostly limited to publications in anaesthesiology journals. We therefore summarise general recommendations and specific advice for anaesthesia in different neuromuscular disorders to provide a comprehensive and accessible overview of the knowledge on this topic essential for clinical neurologists. A preoperative multidisciplinary approach involving anaesthesiologists, cardiologists, chest physicians, surgeons and neurologists is crucial. Depolarising muscle relaxants (succinylcholine) should be avoided at all times. The dose of non-depolarising muscle relaxants must be reduced and their effect monitored. Patients with specific mutations in RYR1 (ryanodine receptor 1) and less frequently in CACNA1S (calcium channel, voltage-dependent, L type, alpha 1S subunit) and STAC3 (SH3 and cysteine rich domain 3) are at risk of developing a life-threatening malignant hyperthermia reaction.

Drugs That Induce or Cause Deterioration of Myasthenia Gravis: An Update

“…MG patients are potentially more sensitive to sedatives and anesthetics [ 120 ]. For example, use of benzodiazepines in MG patients who have significant bulbar symptoms or borderline respiratory reserve could result in respiratory insufficiency by causing a central respiratory depression and obstruction of the upper airways [ 120 ]. High doses of benzodiazepines should preferably be avoided or be used with close monitoring of the respiratory status such as respiratory rate and pulse oximetry.…”

“…There is subsequent muscle relaxation as AChR becomes insensitive to ACh. The action of succinylcholine is not reversed by ACh esterase inhibitors and even enhanced by those medications [ 120 ]. In 1953, Anderson et al reported prolonged apnea after use of succinylcholine to remove bronchial tumor in a patient with myasthenia, in retrospect a likely Lambert–Eaton syndrome [ 125 ].…”

“…On the other hand, Eisenkraft et al showed that MG patients are more resistant to IV succinylcholine because of fewer AChRs and did not have prolonged postoperative weakness [ 126 ]. Succinylcholine is generally avoided in neuromuscular diseases, especially those associated with severe lower motor neuron disease, as it may result in severe hyperkalemia [ 120 ]. However, it is not absolutely contraindicated in MG [ 127 ].…”

“…However, it is not absolutely contraindicated in MG [ 127 ]. Nondepolarizing NMBs rocuronium, mivacurium, vecuronium and pancuronium, cause muscle relaxation by reversibly blocking AChRs without activating it [ 120 ]. MG patients are more sensitive than normal controls to nondepolarizing neuromuscular blockers, and the amount of block can be prolonged and unpredictable [ 128 ].…”

“…MG patients are more sensitive than normal controls to nondepolarizing neuromuscular blockers, and the amount of block can be prolonged and unpredictable [ 128 ]. If nondepolarizing NMBs are used in MG patients a lower dose should be used guided by repetitive nerve stimulation—i.e., train of fours [ 120 , 128 ]. Itoh et al reported that patients with ocular MG are less sensitive to vecuronium with slower onset of block compared to those with generalized MG, when assessed by repetitive nerve stimulation [ 129 ].…”