Clinical Outcomes of Critical Illness Polyneuropathy



Pharmacotherapy. 2002;22(3) 

In This Article

Abstract and Introduction


It is often difficult to isolate the origin of acute weakness in the critically ill population because of multiple etiologies. Aminoglycosides, corticosteroids, and neuromuscular blockers frequently are implicated as the source of acute weakness. Recently, critical illness polyneuropathy (CIP), a syndrome of unknown etiology, was added to the differential diagnosis. The frequency of CIP is approximately 70% in patients with sepsis. Early studies of CIP, which were mostly retrospective, underestimated its frequency due to the complexity of the diagnosis and unfamiliarity with the syndrome. Prospective studies have explored the causality and clinical outcomes of CIP. Clinical outcomes of patients with CIP include difficulty weaning from mechanical ventilation, increased length of stay, prolonged recovery, and an overall mortality rate of 26-71%. The association of CIP with sepsis, multiorgan failure, and drugs is still unclear.


The pharmacist's primary responsibility is to ensure patient safety by identifying drug-related complications. Aminoglycosides, corticosteroids, and neuromuscular blockers (NMBs) frequently are considered causes of acute weakness in critically ill patients. The complexity of critical illness and numerous contributing factors make it difficult to isolate the primary source of the weakness in these patients. Recently, critical illness polyneuropathy (CIP) was added to the list of syndromes in the differential diagnosis of acute weakness.

The term CIP, coined in 1984,[1] is defined as a predominantly motor axonal dysfunction of unknown etiology. It emerges with acute onset following development of respiratory insuffi-ciency in patients with systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction.[1,2] Critical illness polyneuropathy occurs primarily in adults, although a few cases were reported in children.[3,4] The frequency of CIP is 70% in patients who develop sepsis and multiple organ dysfunction and up to 80% in patients with SIRS.[5,6,7] It is difficult, however, to identify CIP with certainty, due to the complexity of critical illness.

Critical illness polyneuropathy is diagnosed by clinical presentation (difficulty in weaning from the ventilator and limb weakness)and electrophysiologic findings (nerve conduction and needle electromyography [EMG]). A 5-year retrospective evaluation of 497 critically ill patients revealed no identifiable cases of severe prolonged generalized weakness.[8] Subsequently, the same research group completed a 2-year prospective study and diagnosed six patients with CIP.[8] This demonstrates that retrospective investigations of CIP may underestimate its occurrence due to the complexity of the diagnosis and clinicians' past unfamiliarity with the syndrome. Therefore, prospective studies provide a more accurate description of CIP.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: