AIMS. Our objective was 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 of them 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. 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.

Objetivo Analizar las causas y manifestaciones de la debilidad muscular que desarrollan los pacientes críticos durante su estancia en la UCI y revisar la bibliografía.

Desarrollo A principios de los años ochenta, Bolton describió una polineuropatía axonal mixta que denominó ‘polineuropatía del paciente crítico’. Clínicamente se caracterizaba por una debilidad muscular de intensidad variable que en su vertiente más grave producía tetraplejia y/o dependecia del ventilador. Actualmente se considera que es la alteración neurológica más frecuente en los pacientes críticos. Muchos de ellos se recuperabanad integrum tras un período de varios meses o, incluso, un año. Casi paralelamente se describió ‘la miopatía aguda de los cuidados intensivos’ en pacientes asmáticos que eran ingresados en la UCI por exacerbación de su enfermedad. Con posterioridad se observó que esta miopatía se presentaba también en otro tipo de pacientes: trasplantados, sépticos o quemados. Hay autores que consideran la miopatía aguda de los cuidados intensivos como la primera causa de debilidad muscular en la UCI.

Conclusiones La ‘polineuropatía del paciente crítico’ y la ‘miopatía aguda de los cuidados intensivos’ son diferenciables en muchas ocasiones, y para ello son de gran ayuda los estudios neurofisiológicos y, eventualmente, la biopsia muscular. Aunque algunos autores prefieren englobar estas entidades bajo el nombre de ‘polineuromiopatía’, proponemos la denominación general de ‘síndrome neuromuscular adquirido en el paciente crítico’, término más descriptivo que no presupone un mecanismo, ni una etiología única.