Anaesthesia in Patients with Neuromuscular Diseases -New Concepts for Old Problems?

Patients with neuromuscular diseases (NMD) present numerous, clinically relevant special features; the perioperative care of this patient group requires therefore specific knowledge and anaesthesiological concepts.

Many NMD are very rare, for example Duchenne's muscular dystrophy with about 3 : 10.000 living-finally births is quietly the most frequent form of inherited muscle dystrophies. Other NMD show even smaller incidences and anaesthesiological experiences are mostly presented only by case reports. For the anaesthesiological care of these patients comes complicating in addition, that some NMD are clinically at first unrecognized and possibly not known at the time of anaesthesia. For example children with Becker's muscular dystrophy show first in the age of 6 - 9 years first symptoms of the illness. In addition some of these illnesses can occur in every age, as the myasthenia, that can manifest already neonatal, but also in the adulthood.

Most NMD lead to a raised sensitiveness for specific anaesthetics, according to this the risk for rhabdomyolysis following administration of succinylcholine is dramatically increased in some of these diseases. But also other anaesthetics, as for example volatile inhalational anaesthetics or non-depolarizing muscle relaxants (ndMR), can endanger the patient. Furthermore, the potency and the duration of action of numerous anaesthetics are pathologically changed in neuromuscular sick patients, on the one hand the duration of action from ndMR at myasthenia is increased considerably, and on the other hand the patients show a raised resistance for succinylcholine. However, the effects of the anaesthetics are at numerous NMD examined up to now only inadequately, studies at larger patient populations are not as a rule possible and suitable animal-experimentally models are missing until now.

For some illnesses, as for example the Central Core Disease, due to the narrow genetic link-up, an increased risk for a disposition for the malignant hyperthermia (MH) was described. At numerous other NMD there are on the other hand inconsistent statements about an association with MH.

Next to the known muscular problems which can lead to an alteration of the pulmonary functions additional anaesthesia-relevantly factors of risk exist in most cases. Numerous NMD are for example associated with a raised incidence of accompanying cardiac alterations, including heart failure, clinically inapparent rhythm disturbances up to cardiomyopathies with secondary valve insufficiency and finally cardiac decompensation and death.

Before the background of the problems above exemplarily presented, it can be concluded that the incidence from perioperative complications within this patient group is significantly increased. The question by which anaesthesiological concepts, as for example the use of modern, short-acting anaesthetics, the safety for NMD-patients can be improved is not sufficiently answered until now.

For the representation and discussion of these clinical problems a symposium with the title "Current aspects of the anaesthesia in patients with neuromuscular diseases" was held in the Doctor chamber of Hamburg. In this symposium well-known experts have presented from a neurological, an anaesthesiological as well as a legally viewpoint, the essential aspects of anaesthesia in the neuromuscular sick patient. The present symposium was aimed to present all relevant features of neuromuscular diseases, like prae- and intraoperative diagnostic and the anaesthesiological management. Furthermore, current discoveries in MH are presented and neurological complications from patient positioning and after regional anaesthesia are crucially illuminated.

In case of knowledge of the specific pathophysiology and features of the NMD, the perioperative care can nowadays surely be performed in patients with neuromuscular diseases. However, for improvement of the anaesthesiological management further systematic investigations at the patient as well as the establishment of more expressively animal-experimentally models would be desirable.