Aims: To analyse the causes and signs of the muscle weakness that critically ill patients develop during their stay in the ICU and to review the literature.
Development: In the early 80s, Bolton reported a mixed axonal polyneuropathy that he called 'polyneuropathy in critically ill patients'. Clinically it was characterised by muscle weakness that varied in intensity and caused quadriplegia and/or the need for assisted ventilation in its severest forms. It is currently considered to be the most common neurological disorder among critically ill patients. Many patients made a complete recovery after a few months or even a year. Running almost parallel to this, he also described 'acute myopathy in intensive care' among asthmatic patients who were hospitalised in the ICU due to exacerbation of their illness. It was later observed how other types of patients also had this myopathy, for instance, those who had undergone a transplant, sepsis or burns. Some authors consider acute myopathy in intensive care to be the primary cause of muscle weakness in the ICU.
Conclusions: On many occasions 'polyneuropathy of critically ill patients' and 'acute myopathy in intensive care' can be differentiated and to do so neurophysiological and, if necessary, muscle biopsy studies are a valuable aid. Although some authors prefer to group these conditions under the name 'polyneuromyopathy', we propose the general term 'acquired neuromuscular syndrome in critically ill patients' -a more descriptive expression that does not presuppose a particular mechanism or a single aetiology.