Long-term recovery In critical illness myopathy is complete, contrary to polyneuropathy

Clinical review: intensive care unit acquired weakness

A substantial number of patients admitted to the ICU because of an acute illness, complicated surgery, severe trauma, or burn injury will develop a de novo form of muscle weakness during the ICU stay that is referred to as “intensive care unit acquired weakness” (ICUAW). This ICUAW evoked by critical illness can be due to axonal neuropathy, primary myopathy, or both. Underlying pathophysiological mechanisms comprise microvascular, electrical, metabolic, and bioenergetic alterations, interacting in a complex way and culminating in loss of muscle strength and/or muscle atrophy. ICUAW is typically symmetrical and affects predominantly proximal limb muscles and respiratory muscles, whereas facial and ocular muscles are often spared. The main risk factors for ICUAW include high severity of illness upon admission, sepsis, multiple organ failure, prolonged immobilization, and hyperglycemia, and also older patients have a higher risk. The role of corticosteroids and neuromuscular blocking agents remains unclear. ICUAW is diagnosed in awake and cooperative patients by bedside manual testing of muscle strength and the severity is scored by the Medical Research Council sum score. In cases of atypical clinical presentation or evolution, additional electrophysiological testing may be required for differential diagnosis. The cornerstones of prevention are aggressive treatment of sepsis, early mobilization, preventing hyperglycemia with insulin, and avoiding the use parenteral nutrition during the first week of critical illness. Weak patients clearly have worse acute outcomes and consume more healthcare resources. Recovery usually occurs within weeks or months, although it may be incomplete with weakness persisting up to 2 years after ICU discharge. Prognosis appears compromised when the cause of ICUAW involves critical illness polyneuropathy, whereas isolated critical illness myopathy may have a better prognosis. In addition, ICUAW has shown to contribute to the risk of 1-year mortality. Future research should focus on new preventive and/or therapeutic strategies for this detrimental complication of critical illness and on clarifying how ICUAW contributes to poor longer-term prognosis.

Critical illness polyneuropathy and myopathy in a rural area in Vietnam

INTRODUCTION

Critical illness polyneuropathy, myopathy and polyneuromyopathy, grouped under the term CIP/CIM, share several risk factors and are associated with debilitating outcomes.

OBJECTIVE

To assess the incidence and distribution of CIP/CIM subtypes and evaluate the risk factors and outcomes of CIP/CIM in a rural hospital in Vietnam.

METHOD

One hundred and thirty three critically ill patients treated more than ten days in the ICU were enrolled. The Medical Research Council (MRC) sum scores and the Overall Neuropathy Limitations Scale (ONLS) score were calculated and risk factors were monitored. Extensive electrodiagnostic investigations were performed to confirm the diagnosis of CIP/CIM.

RESULTS

CIP/CIM was diagnosed in 73 (55%) patients. The distribution of polyneuropathy, myopathy and polyneuromyopathy was 35 (48%), 16 (22%) and 22 (30%), respectively. Independent risk factors included systemic inflammatory response syndrome, shock, and electrolyte disturbances. Compared to patients without CIP/CIM, patients with CIP/CIM experienced a mortality rate of 49% vs. 30%, a length of stay in ICU of 20.3days vs. 14.3days, an ONLS score at day thirty of 4.2 vs. 1.3 and at day ninety of 2.7 vs. 1.8.

CONCLUSION

The study revealed that the diagnosis of CIP/CIM was associated with significantly poorer outcomes in comparison to controls.

Impact of ICU-acquired weakness on post-ICU physical functioning: a follow-up study

Introduction

ICU-acquired weakness is thought to mediate physical impairments in survivors of critical illness, but few studies have investigated this thoroughly. The purpose was to investigate differences in post-ICU mortality and physical functioning between patients with and without ICU-acquired weakness at 6 months after ICU discharge.

Method

ICU patients, mechanically ventilated ≥2 days, were included in a single-center prospective observational cohort study. ICU-acquired weakness was diagnosed when the average Medical Research Council score was <4 in awake and attentive patients. Post-ICU mortality was recorded until 6 months after ICU discharge; in surviving patients, physical functioning was assessed using the Short-Form Health Survey physical functioning domain. The independent effect of ICU-acquired weakness on post-ICU mortality was analyzed using a multivariable Cox proportional hazards model. The independent effect of ICU-acquired weakness on the physical functioning domain score was analyzed using a multivariable linear regression model.

Results

Of the 156 patients included, 80 had ICU-acquired weakness. Twenty-three patients died in the ICU (20 with ICU-acquired weakness); during 6 months follow-up after ICU discharge another 25 patients died (17 with ICU-acquired weakness). Physical functioning domain scores were available for 96 survivors (39 patients with ICU-acquired weakness). ICU-acquired weakness was independently associated with an increase in post-ICU mortality (hazard ratio 3.6, 95% confidence interval, 1.3 to 9.8; P = 0.01) and with a decrease in physical functioning (β: -16.7 points; 95% confidence interval, -30.2 to -3.1; P = 0.02).

Conclusion

ICU-acquired weakness is independently associated with higher post-ICU mortality and with clinically relevant lower physical functioning in survivors at 6 months after ICU discharge.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-0937-2) contains supplementary material, which is available to authorized users.

[Neurological and psychological long-term effects of sepsis]

BACKGROUND

In addition to the limitations to the health-related quality of life that have been compiled with validated test instruments, a number of former sepsis patients suffer from functional impairments, which are categorized under the terms critical illness polyneuropathy (CIP) or critical illness myopathy (CIM), which have been in existence for over 20 years now.

CURRENT FOCUS

The issues of delirium during intensive therapy and persistent residual neurocognitive impairments, posttraumatic stress disorder (PTSD) and states of depression related to perihospital functional development have increasingly attracted notice.

FUTURE

The degree of functional deficits resulting from sepsis and the actual quality of life of those affected may, however, be influenced by taking appropriate rehabilitation measures. However, neither therapeutic rehabilitation standards nor any rehabilitation facilities tailored to the needs of these patients currently exist.

Validation of the peroneal nerve test to diagnose critical illness polyneuropathy and myopathy in the intensive care unit: the multicentre Italian CRIMYNE-2 diagnostic accuracy study

OBJECTIVES

To evaluate the accuracy of the peroneal nerve test (PENT) in the diagnosis of critical illness polyneuropathy (CIP) and myopathy (CIM) in the intensive care unit (ICU). We hypothesised that abnormal reduction of peroneal compound muscle action potential (CMAP) amplitude predicts CIP/CIM diagnosed using a complete nerve conduction study and electromyography (NCS-EMG) as a reference diagnostic standard.

DESIGN

prospective observational study.

SETTING

Nine Italian ICUs.

PATIENTS

One-hundred and twenty-one adult (≥18 years) neurologic (106) and non-neurologic (15) critically ill patients with an ICU stay of at least 3 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PATIENTS underwent PENT and NCS-EMG testing on the same day conducted by two independent clinicians who were blind to the results of the other test. Cases were considered as true negative if both NCS-EMG and PENT measurements were normal. Cases were considered as true positive if the PENT result was abnormal and NCS-EMG showed symmetric abnormal findings, independently from the specific diagnosis by NCS-EMG (CIP, CIM, or combined CIP and CIM). All data were centrally reviewed and diagnoses were evaluated for consistency with predefined electrophysiological diagnostic criteria for CIP/CIM. During the study period, 342 patients were evaluated, 124 (36.3%) were enrolled and 121 individuals with no protocol violation were studied. Sensitivity and specificity of PENT were 100% (95% CI 96.1-100.0) and 85.2% (95% CI 66.3-95.8). Of 23 patients with normal results, all presented normal values on both tests with no false negative results. Of 97 patients with abnormal results, 93 had abnormal values on both tests (true positive), whereas four with abnormal findings with PENT had only single peroneal nerve neuropathy at complete NCS-EMG (false positive).

CONCLUSIONS

PENT has 100% sensitivity and high specificity, and can be used to diagnose CIP/CIM in the ICU.

Validation of the peroneal nerve test to diagnose critical illness polyneuropathy and myopathy in the intensive care unit: the multicentre Italian CRIMYNE-2 diagnostic accuracy study

OBJECTIVES

To evaluate the accuracy of the peroneal nerve test (PENT) in the diagnosis of critical illness polyneuropathy (CIP) and myopathy (CIM) in the intensive care unit (ICU). We hypothesised that abnormal reduction of peroneal compound muscle action potential (CMAP) amplitude predicts CIP/CIM diagnosed using a complete nerve conduction study and electromyography (NCS-EMG) as a reference diagnostic standard.

DESIGN

prospective observational study.

SETTING

Nine Italian ICUs.

PATIENTS

One-hundred and twenty-one adult (≥18 years) neurologic (106) and non-neurologic (15) critically ill patients with an ICU stay of at least 3 days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

PATIENTS underwent PENT and NCS-EMG testing on the same day conducted by two independent clinicians who were blind to the results of the other test. Cases were considered as true negative if both NCS-EMG and PENT measurements were normal. Cases were considered as true positive if the PENT result was abnormal and NCS-EMG showed symmetric abnormal findings, independently from the specific diagnosis by NCS-EMG (CIP, CIM, or combined CIP and CIM). All data were centrally reviewed and diagnoses were evaluated for consistency with predefined electrophysiological diagnostic criteria for CIP/CIM. During the study period, 342 patients were evaluated, 124 (36.3%) were enrolled and 121 individuals with no protocol violation were studied. Sensitivity and specificity of PENT were 100% (95% CI 96.1-100.0) and 85.2% (95% CI 66.3-95.8). Of 23 patients with normal results, all presented normal values on both tests with no false negative results. Of 97 patients with abnormal results, 93 had abnormal values on both tests (true positive), whereas four with abnormal findings with PENT had only single peroneal nerve neuropathy at complete NCS-EMG (false positive).

CONCLUSIONS

PENT has 100% sensitivity and high specificity, and can be used as a screening test to diagnose CIP/CIM in the ICU.