From the Guidelines
Critical illness polyneuropathy (CIP) typically develops within 2 to 5 days of ICU admission in critically ill patients, though it can sometimes take up to 1-2 weeks to manifest clinically. The condition most commonly affects patients with sepsis, systemic inflammatory response syndrome (SIRS), or multiple organ failure who require mechanical ventilation. Early signs include muscle weakness, particularly in the limbs, and difficulty weaning from mechanical ventilation. The development of CIP is related to microcirculatory changes, metabolic alterations, and inflammatory mediators that damage peripheral nerves during critical illness. Risk factors include hyperglycemia, use of neuromuscular blocking agents, corticosteroids, and prolonged immobility.
Some key points to consider in the development of CIP include:
- The use of intensive insulin therapy (IIT) to achieve strict glycemic control may reduce the risk of CIP, as seen in a study published in Critical Care Medicine 1
- Prolonged continuous infusion of neuromuscular blocking agents (NMBAs) in medical ICU patients was an independent risk factor for at least one abnormal result on an electrophysiologic test for CIPNM, as noted in the same study 1
- Guidelines for insulin infusion for patients in the ICU suggest maintaining a blood glucose concentration of less than 180 mg/dL, although targeting lower glucose values may be advantageous in specific populations if it can be done with a minimal risk of hypoglycemia 1
- Screening for risk factors to develop post-intensive care syndrome (PICS), which includes CIP, is important during the stay in intensive care, after discharge, and during rehabilitation, as stated in a guideline published in Critical Care 1
Diagnosis of CIP is typically confirmed through nerve conduction studies and electromyography, which show axonal degeneration. Early recognition is crucial, as management focuses on treating the underlying critical illness, maintaining normoglycemia, early mobilization, and providing supportive care to prevent complications while the nervous system recovers, which may take weeks to months.
From the Research
Duration of Development for Critical Illness Polyneuropathy (CIP)
- The development of CIP is associated with the duration of critical illness and the severity of the underlying condition 2, 3.
- CIP represents an acute axonal neuropathy that develops during treatment of severely ill patients and remits spontaneously, once the critical condition is under control 2.
- The course of CIP is monophasic and self-limiting 2.
- Risk factors for the development of long-term critical illness neuropathy include duration of ICU treatment, duration of ventilator support, and a high APACHE score 3.
- Electrophysiological signs of CIP can be observed as early as 10 days after ICU admission, with most patients featuring concomitant critical illness myopathy (CIM) 4.
- The duration of CIP can vary, but it is often associated with a prolonged ICU stay, with patients having combined CIM/CIP showing a significantly longer length of stay compared to those with isolated CIM 4.