Electrophysiological Screening to Assess Foot Drop Syndrome in Severe Acquired Brain Injury in Rehabilitative Settings

BACKGROUND

Foot drop syndrome (FDS), characterized by severe weakness and atrophy of the dorsiflexion muscles of the feet, is commonly found in patients with severe acquired brain injury (ABI). If the syndrome is unilateral, the cause is often a peroneal neuropathy (PN), due to compression of the nervous trunk on the neck of the fibula at the knee level; less frequently, the cause is a previous or concomitant lumbar radiculopathy. Bilateral syndromes are caused by polyneuropathies and myopathies. Central causes, due to brain or spinal injury, mimic this syndrome but are usually accompanied by other symptoms, such as spasticity. Critical illness polyneuropathy (CIP) and myopathy (CIM), isolated or in combination (critical illness polyneuromyopathy, CIPNM), have been shown to constitute an important cause of FDS in patients with ABI. Assessing the causes of FDS in the intensive rehabilitation unit (IRU) has several limitations, which include the complexity of the electrophysiological tests, limited availability of neurophysiology consultants, and the severe disturbance in consciousness and lack of cooperation from patients.

OBJECTIVES

We sought to propose a simplified electrophysiological screening that identifies FDS causes, particularly PN and CIPNM, to help clinicians to recognize the significant clinical predictors of poor outcomes in severe ABI at admission to IRU.

METHODS

This prospective, single-center study included 20 severe ABI patients with FDS (11 females/9 males, mean age 55.10 + 16.26; CRS-R= 11.90 + 6.32; LCF: 3.30 + 1.30; DRS: 21.45 + 3.33), with prolonged rehabilitation treatment (≥2 months). We applied direct tibialis anterior muscle stimulation (DMS) associated with peroneal nerve motor conduction evaluation, across the fibular head (NCS), to identify CIP and/or CIM and to exclude demyelinating or compressive unilateral PN.

RESULTS

At admission to IRU, simplified electrophysiological screening reported four unilateral PN, four CIP and six CIM with a CIPNM overall prevalence estimate of about 50%. After 2 months, the CIPNM group showed significantly poorer outcomes compared to other ABI patients without CIPNM, as demonstrated by the lower probability of achieving endotracheal-tube weaning (20% versus 90%) and lower CRS-R and DRS scores. Due to the subacute rehabilitation setting of our study, it was not possible to evaluate the motor results of recovery of the standing position, functional walking and balance, impaired by the presence of unilateral PN.

CONCLUSIONS

The implementation of the proposed simplified electrophysiological screening may enable the early identification of unilateral PN or CIPNM in severe ABI patients, thereby contributing to better functional prognosis in rehabilitative settings.

Critical Illness Polyneuropathy in a Child: A Case Report

Critical illness polyneuropathy (CIP) and myopathy (CIM) are underreported conditions in critically ill children with prolonged intensive care unit stays and mechanical ventilation. We report a case of a 10-year-old boy with pneumococcal meningoencephalitis with severe sepsis and multiorgan dysfunction. The child required prolonged ventilation, sedation, and inotropic support. He had repeated extubation failures and the development of quadriparesis with areflexia. Electrophysiology studies were consistent with CIP with acute motor and sensory axonal polyneuropathy and elevated muscle enzymes. He was treated with supportive measures and physiotherapy along with management of the underlying condition. He recovered slowly over 68 days with a good recovery with a modified Rankin's scale score of 4 on discharge. There is a need to pay attention to all critically ill children and should have a high index of suspicion for the development of CIP/CIM which can have an impact on course and outcome.

Intensive Care Unit-Acquired Weakness after Liver Transplantation: Analysis of Seven Cases and a Literature Review

Intensive Care Unit (ICU)-Acquired Weakness (ICU-AW) is a generalized muscle weakness that is clinically detected in critical patients and has no plausible etiology other than critical illness. ICU-AW is uncommon in patients undergoing orthotopic liver transplantation (OLT). Our report sheds light on the highest number of ICU-AW cases observed in a single center on OLT patients with early allograft dysfunction. Out of 282 patients who underwent OLT from January 2015 to June 2023, 7 (2.5%) developed generalized muscle weakness in the ICU and underwent neurophysiological investigations. The neurologic examination showed preserved extraocular, flaccid quadriplegia with the absence of deep tendon reflexes in all patients. Neurophysiological studies, including electromyography and nerve conduction studies, showed abnormalities with fibrillation potentials and the rapid recruitment of small polyphasic motor units in the examined muscles, as well as a reduced amplitude of the compound muscle action potential and sensory nerve action potential, with an absence of demyelinating features. Pre-transplant clinical status was critical in all patients. During ICU stay, early allograft dysfunction, acute kidney injury, prolonged mechanical ventilation, sepsis, hyperglycemia, and high blood transfusions were observed in all patients. Two patients were retransplanted. Five patients were alive at 90 days; two patients died. In non-cooperative OLT patients, neurophysiological investigations are essential for the diagnosis of ICU-AW. In this setting, the high number of red blood cell transfusions is a potential risk factor for ICU-AW.

COVID-19-Induced Myopathy and Diaphragmatic Weakness: A Case Report

Coronavirus disease 2019 (COVID-19) is a respiratory illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus that can induce myopathy, which can evolve into potentially life-threatening muscle weakness, including diaphragmatic paralysis. We present a case report of a 57-year-old female treated in the medical ICU for acute respiratory distress syndrome (ARDS) triggered by active COVID-19 infection, who subsequently developed worsening respiratory weakness from underlying COVID-19 myopathy manifesting as respiratory muscle weakness. Our patient's muscle biopsy highlights the development of muscle atrophy without evidence of inflammatory myopathy, making the presence of pre-existing autoimmune myopathy unlikely. While literature cites different biochemical etiologies for the development of myopathy, the exact mechanism behind this phenomenon is not yet defined.

Neuromuscular Ultrasound in Intensive Care Unit-Acquired Weakness: Current State and Future Directions

Intensive care unit-acquired weakness (ICUAW) is one of the most common causes of muscle atrophy and functional disability in critically ill intensive care patients. Clinical examination, manual muscle strength testing and monitoring are frequently hampered by sedation, delirium and cognitive impairment. Many different attempts have been made to evaluate alternative compliance-independent methods, such as muscle biopsies, nerve conduction studies, electromyography and serum biomarkers. However, they are invasive, time-consuming and often require special expertise to perform, making them vastly impractical for daily intensive care medicine. Ultrasound is a broadly accepted, non-invasive, bedside-accessible diagnostic tool and well established in various clinical applications. Hereby, neuromuscular ultrasound (NMUS), in particular, has been proven to be of significant diagnostic value in many different neuromuscular diseases. In ICUAW, NMUS has been shown to detect and monitor alterations of muscles and nerves, and might help to predict patient outcome. This narrative review is focused on the recent scientific literature investigating NMUS in ICUAW and highlights the current state and future opportunities of this promising diagnostic tool.

COVID-19 Vaccination a Cause of Guillain-Barré Syndrome? A Case Series

Guillain-Barré syndrome (GBS) is a rare autoimmune neuropathic disorder of peripheral nerves usually following an infection or on rarer occasions following vaccinations, but the exact underlying pathophysiology is still unclear. The most common etiology of GBS is a bacterial infection caused by Campylobacter jejuni. Viral infections like Zika virus, Epstein-Barr virus, and Cytomegalovirus also add to the list of GBS etiology. COVID-19 (SARS-CoV-2) has also been reported to cause GBS. Vaccines like the rabies vaccine, influenza vaccine, and poliovirus vaccine account for a very small fraction of Guillain-Barré syndrome. GBS as an adverse effect of COVID-19 vaccination was not reported by the Vaccine Adverse Event Reporting System (VAERS), but an update was later released in the course of the pandemic from FDA news, reporting several patients developing GBS after receiving the COVID-19 vaccine. In this case series, we discuss five cases that developed the GBS post-COVID-19 AstraZeneca vaccine, along with its pathophysiology, management, and outcome.

A Global Survey on Diagnostic, Therapeutic and Preventive Strategies in Intensive Care Unit-Acquired Weakness

Background and Objectives: Intensive care unit-acquired weakness (ICU-AW) is one of the most frequent neuromuscular complications in critically ill patients. We conducted a global survey to evaluate the current practices of diagnostics, treatment and prevention in patients with ICU-AW. Materials and Methods: A pre-survey was created with international experts. After revision, the final survey was endorsed by the European Society of Intensive Care Medicine (ESICM) using the online platform SurveyMonkey®. In 27 items, we addressed strategies of diagnostics, therapy and prevention. An invitation link was sent by email to all ESICM members. Furthermore, the survey was available on the ESICM homepage. Results: A total of 154 healthcare professionals from 39 countries participated in the survey. An ICU-AW screening protocol was used by 20% (28/140) of participants. Forty-four percent (62/141) of all participants reported performing routine screening for ICU-AW, using clinical examination as the method of choice (124/141, 87.9%). Almost 63% (84/134) of the participants reported using current treatment strategies for patients with ICU-AW. The use of treatment and prevention strategies differed between intensivists and non-intensivists regarding the reduction in sedatives (80.0% vs. 52.6%, p = 0.002), neuromuscular blocking agents (76.4% vs. 50%, p = 0.004), corticosteroids (69.1% vs. 37.2%, p < 0.001) and glycemic control regimes (50.9% vs. 23.1%, p = 0.002). Mobilization and physical activity are the most frequently reported treatment strategies for ICU-AW (111/134, 82.9%). The availability of physiotherapists (92/134, 68.7%) and the lack of knowledge about ICU-AW within the medical team (83/134, 61.9%) were the main obstacles to the implementation of the strategies. The necessity to develop guidelines for the screening, diagnosing, treatment and prevention of ICU-AW was recognized by 95% (127/133) of participants. Conclusions: A great heterogeneity regarding diagnostics, treatment and prevention of ICU-AW was reported internationally. Comprehensive guidelines with evidence-based recommendations for ICU-AW management are needed.

Nerve Echogenicity in Polyneuropathies of Various Etiologies-Results of a Retrospective Semi-Automatic Analysis of High-Resolution Ultrasound Images

Echogenicity of peripheral nerves in high-resolution ultrasound (HRUS) provides insight into the structural damage of peripheral nerves in various polyneuropathies. The aim of this study was to compare nerve echogenicity in different primarily axonal or demyelinating polyneuropathies to examine the significance of this parameter. Performing semi-automated echogenicity analysis and applying Image J, we retrospectively used HRUS images of 19 patients with critical illness polyneuropathy (CIP), and 27 patients with chemotherapy-induced polyneuropathy (CIN) and compared them to 20 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). The fraction of black representing echogenicity was measured after converting the images into black and white. The nerves of patients with progressive CIDP significantly differed from the hyperechogenic nerves of patients with other polyneuropathies at the following sites: the median nerve at the forearm (p < 0.001), the median nerve at the upper arm (p < 0.004), and the ulnar nerve at the upper arm (p < 0.001). The other polyneuropathies showed no notable differences. Altogether, the comparison of echogenicity between different polyneuropathies supports the assumption that there are differences depending on the genesis of the structural nerve damage. However, these differences are slight, and cannot be used to show clear differences between each polyneuropathy form.

COVID-19 Neuromuscular Involvement in Post-Acute Rehabilitation

Background: Coronavirus disease 2019 (COVID-19) is associated with muscle and nerve injuries as a consequence of prolonged critical illness or the infection itself. In this study, we evaluated neuromuscular involvement in patients who underwent post-acute intensive rehabilitation after COVID-19. Methods: Clinical and neurophysiological evaluations, including nerve conduction studies and electromyography, were performed on 21 consecutive patients admitted for rehabilitation after COVID-19. Results: Clinical signs suggesting muscle or nerve involvement (weakness, reduced deep tendon reflexes, impaired sensitivity, abnormal gait) were found in 19 patients. Neurophysiological examinations confirmed neuromuscular involvement in 17 patients: a likely association of critical illness myopathy (CIM) and critical illness polyneuropathy (CIP) was found in 5 patients; CIM alone was found in 4 patients; axonal sensory-motor polyneuropathy was found in 4 patients (CIP in 2 patients, metabolic polyneuropathy in 2 patients); Guillain-Barré syndrome was found in 2 patients (classical demyelinating sensory-motor polyneuropathy and acute motor axonal neuropathy, respectively); peroneal nerve injury was found in 1 patient; and pre-existing L4 radiculopathy was found in 1 patient. Conclusions: Neuromuscular involvement is a very common finding among patients admitted for rehabilitation after COVID-19, and proper investigation should be conducted when muscle or nerve injury is suspected for adequate rehabilitative strategy planning.

Intensive Care Unit-Acquired Weakness and Positioning-Related Peripheral Nerve Injuries in COVID-19: A Case Series of Three Patients and the Latest Literature Review

A subgroup of COVID-19 patients requires intensive respiratory care. The prolonged immobilization and aggressive treatments predispose these patients to develop intensive care unit-acquired weakness (ICUAW). Furthermore, this condition could increase the chance of positioning-related peripheral nerve injuries. On the basis of the latest literature review, we describe a case series of three patients with COVID-19 who developed ICUAW complicated by positioning-related peripheral nerve injuries Every patient presented sensorimotor axonal polyneuropathy and concomitant myopathy in electrophysiological studies. Furthermore, muscle MRI helped the diagnosis of ICUAW, showing massive damage predominantly in the proximal muscles. Notably, nerve ultrasound detected positioning-related peripheral nerve injuries, even though the concomitant ICUAW substantially masked their clinical features. During the acute phase of severe COVID-19 infection, most medical attention tends to be assigned to critical care management, and neuromuscular complications such as ICUAW and positioning-related peripheral nerve injuries could be underestimated. Hence, when starting post-ICU care for COVID-19 cases, the combination of electrophysiological and imaging studies will aid appropriate evaluation on the patients with COVID-19-related ICUAW.

High-dose intravenous immunoglobulins as a therapeutic option in critical illness polyneuropathy accompanying SARS-CoV-2 infection: A case-based review of the literature (Review)

The still ongoing COVID-19 pandemic has exposed the medical community to a number of major challenges. A significant number of patients require admission to intensive care unit (ICU) services due to severe respiratory, thrombotic and septic complications and require long-term hospitalization. Neuromuscular weakness is a common complication in critically ill patients who are treated in ICUs and are mechanically ventilated. This complication is frequently caused by critical illness myopathy (CIM) or critical illness polyneuropathy (CIP) and leads to difficulty in weaning from the ventilator. It is thought to represent an important neurologic manifestation of the systemic inflammatory response syndrome (SIRS). COVID-19 infection is known to trigger strong immune dysregulation, with an intense cytokine storm, as a result, the frequency of CIP is expected to be higher in this setting. The mainstay in the diagnosis of this entity beside the high level of clinical awareness is the electrophysiological examination that provides evidence of axonal motor and sensory polyneuropathy. The present article presents the case of a 54-year-old woman with severe COVID 19 infection who developed neuromuscular weakness, which turned out to be secondary to CIP and was treated successfully with a high dose of human intravenous immunoglobulins. Related to this case, we reviewed the relevant literature data regarding the epidemiology, pathophysiology and clinical features of this important complication and discussed also the treatment options and prognosis.

Guillain-Barré Syndrome as a Complication of COVID-19

Coronavirus disease 2019 (COVID-19) is associated with multiple neurological complications including Guillain-Barre syndrome (GBS). While there are reports of COVID-19 -related GBS cases, much remain unknown. We report two cases of GBS-associated COVID-19, which started about eight weeks after the initial COVID-19 infection. Such a long duration between infection and symptom onset of GBS is unusual for post-infectious GBS. Moreover, severely ill patients with COVID-19 may have prolonged hospital stay leading to critical illness myoneuropathy. Diagnosing superimposed GBS can be challenging in such cases. Clinical suspicion, nerve conduction studies with electromyography, and cerebrospinal fluid analysis can help in making the correct diagnosis. Both presented cases responded to intravenous immunoglobulin therapy.

Simplified Diagnosis of Critical Illness Polyneuropathy in Patients with Prolonged Mechanical Ventilation: A Prospective Observational Cohort Study

Background: Although early identification of critical illness polyneuropathy (CIP) is necessary, the established diagnostic criteria have several limitations in the intensive care unit (ICU) setting. The purpose of this study was to define simplified diagnostic criteria of CIP that best predict clinical outcomes. Methods: This prospective, single-center study included 41 ICU patients with prolonged mechanical ventilation (≥21 days). We applied three different sets of diagnostic criteria (combining the results of the Medical Research Council (MRC) sum score and nerve conduction studies (NCS)) for CIP in order to identify the criteria with the best predictive power for clinical outcomes. Results: The simplified diagnosis of CIP meeting the criteria, i.e., that the MRC sum score < 48 and amplitudes of the tibial and sural nerve < 80% of the lower limit of normal, showed the strongest association with 0 ventilator-free days at day 60 (odds ratio, 6.222; p = 0.029). Conclusions: The diagnostic criteria combining the MRC sum score and the tibial and the sural NCS were identified as the simplified criteria of CIP that best predicted the clinical outcomes. The implementation of these simplified criteria may allow for early identification of CIP in the ICU, thereby contributing to prompt interventions for patients with a poor prognosis.

Stiff-person syndrome coexisting with critical illness polyneuropathy: A case report

RATIONALE

Stiff-person syndrome (SPS) is an uncommon neurological disorder with autoimmune features. Here, we report a 60-year-old man with SPS associated with critical illness polyneuropathy (CIP). CIP was diagnosed during an episode of acute respiratory failure secondary to muscular rigidity and spasms, which has rarely been reported in this condition. The overlapping of CIP and SPS complicated the case.

PATIENT CONCERNS

A 60-year-old man presented with gradual onset of cramps, stiffness, and rigidity in his lower limbs 1 year before admission, which eventually led to inability to stand and walk. The persistent nature of his symptoms progressed to frequent acute episodes of dyspnea and he was admitted to intensive care unit (ICU).

DIAGNOSIS

SPS had been diagnosed after 2 tests of electromyography (EMG) and the detection of an elevated anti-GAD65 antibody titer. During the first EMG, low or absent compound muscle action potentials (CMAP), and sensory nerve action potentials (SNAP) were shown. Therefore, the diagnosis of SPS coexisting with CIP was made.

INTERVENTIONS

Symptomatic treatment was initiated with oral clonazepam (0.5 mg Bid) and baclofen (5 mg Bid). Intravenous immunoglobulin (IVIG) (0.4 g/kg/d) was administered for the patient for 5 days after admission. We observed a significant clinical improvement during the administration period, and the patient became ambulatory.

OUTCOMES

On follow-up, the patient reported complete relief of his pain and rigidity.

LESSONS

We report this special case to address the varied clinical features of SPS. Electrophysiological testing is an important diagnostic approach. Accurate recognition of the disease ensures that the patients can be given appropriate treatment without delay.

Intensive Care Unit-Acquired Weakness: Not just Another Muscle Atrophying Condition

Intensive care unit-acquired weakness (ICUAW) occurs in critically ill patients stemming from the critical illness itself, and results in sustained disability long after the ICU stay. Weakness can be attributed to muscle wasting, impaired contractility, neuropathy, and major pathways associated with muscle protein degradation such as the ubiquitin proteasome system and dysregulated autophagy. Furthermore, it is characterized by the preferential loss of myosin, a distinct feature of the condition. While many risk factors for ICUAW have been identified, effective interventions to offset these changes remain elusive. In addition, our understanding of the mechanisms underlying the long-term, sustained weakness observed in a subset of patients after discharge is minimal. Herein, we discuss the various proposed pathways involved in the pathophysiology of ICUAW, with a focus on the mechanisms underpinning skeletal muscle wasting and impaired contractility, and the animal models used to study them. Furthermore, we will explore the contributions of inflammation, steroid use, and paralysis to the development of ICUAW and how it pertains to those with the corona virus disease of 2019 (COVID-19). We then elaborate on interventions tested as a means to offset these decrements in muscle function that occur as a result of critical illness, and we propose new strategies to explore the molecular mechanisms of ICUAW, including serum-related biomarkers and 3D human skeletal muscle culture models.

Advances in the rehabilitation of intensive care unit acquired weakness: A case report on the promising use of robotics and virtual reality coupled to physiotherapy

INTRODUCTION

Traditional physiotherapy is currently the best approach to manage patients with intensive care unit acquired weakness (ICUAW). We report on a patient with ICUAW, who was provided with an intensive, in-patient regimen, that is, conventional plus robot-assisted physiotherapy. Aim of this case study was to assess the efficacy of a combined approach (conventional plus robot-assisted physiotherapy), on muscle strength, overall mobility, and disability burden in a patient with ICUAW in post-ICU intensive rehabilitation setting.

PATIENT CONCERNS

A 56-years-old male who was unable to stand and walk independently after hospitalization in an Intensive Care Unit. He initially was provided with daily sessions of conventional physiotherapy for 2 months, with mild results.

DIAGNOSIS

The patient was affected by ICUAW.

INTERVENTION

Given that the patient showed a relatively limited improvement after conventional physiotherapy, he was provided with daily sessions of robot-aided training for upper and lower limbs and virtual reality-aided rehabilitation for other 4 months, beyond conventional physiotherapy.

OUTCOMES

At the discharge (6 months after the admission), the patient reached the standing station and was able to ambulate with double support.

CONCLUSIONS

Our case suggests that patients with ICUAW should be intensively treated in in-patient regimen with robot-aided physiotherapy. Even though our approach deserves confirmation, the combined rehabilitation strategy may offer some advantage in maximizing functional recovery and containing disability.

The Ameliorative Effects of Ascorbic Acid on Critical Illness Polyneuropathy in Rodent Sepsis Model

Although the exact pathophysiology of critical illness polyneuropathy (CIP) is still unknown, there are several hypotheses, some of which are increased inflammation and oxidative stress. We used rodent sepsis model in which we induced sepsis through cecal ligation followed by cecal puncture. We then administered ascorbic acid (AA) and evaluated outcomes. The levels of malondialdehyde (MDA), tumor necrosis factor α (TNF-α), interleukins (IL)-6 in the plasma, and heat shock protein-70 (HSP-70) levels in the sciatic nerve were measured, and also electromyography analyses were performed. While plasma MDA, TNF-α, and IL-6 levels were decreased significantly with AA treatment, sciatic nerve levels of HSP-70 were significantly elevated in the AA group. A significant increase in compound muscle action potential (CMAP) amplitude and a significant decrease in CMAP latency were detected in the AA group. We observed healing effects of AA on a rat model of CIP and these effects seem to be related to its anti-inflammatory and antioxidant properties.

No association between systemic complement activation and intensive care unit-acquired weakness

Background

The main risk factors for intensive care unit-acquired weakness (ICU-AW) are sepsis, the systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction. These risk factors are associated with systemic complement activation. We hypothesized that critically ill patients who develop ICU-AW have increased systemic complement activation compared to critically ill patients who do not develop ICU-AW.

Methods

Complement activation products C3b/c, C4b/c and C5a were measured in plasma of ICU patients with mechanical ventilation for ≥48 hours. Samples were collected at admission to the ICU and for 6 consecutive days. ICU-AW was defined by a mean Medical Research Council (MRC) score <4. We compared the level of complement activation products between patients who did and who did not develop ICU-AW.

Results

Muscle strength measurements and complement assays were available in 27 ICU patients, of whom 13 patients developed ICU-AW. Increased levels of C4b/c were seen in all patients. Neither admission levels, nor maximum, minimum and mean levels of complement activation products were different between patients who did and did not develop ICU-AW.

Conclusions

Complement activation is seen in critically ill patients, but is not different between patients who did and who did not develop ICU-AW.

Electrodiagnostic studies in the intensive care unit: A comparison study 2 decades later

INTRODUCTION

Since the late 1980s, critical illness myopathy (CIM) and critical illness polyneuropathy (CIP) have been increasingly recognized in the intensive care unit (ICU). We explored whether these causes of ICU weakness were now more likely to lead to electrodiagnostic studies (EDX) at our institution than they were 19-20 years earlier.

METHODS

We reviewed 100 consecutive ICU patients who underwent EDX from 2009 to 2015 and compared them to a previously reported study population from 1990-1995.

RESULTS

Thirty-seven (39%) had CIM, CIP, or both versus 55% in the previous study (P = 0.04). Thirty-four (36%) were diagnosed with "traditional" pre-ICU causes of weakness, such as motor neuron disease or Guillain-Barre syndrome, versus 29% in the earlier study (P = 0.3).

DISCUSSION

CIM and CIP continue to be common disorders that lead to ICU EDX, but their proportion declined compared with 19-20 years earlier, possibly due to the perceived role and selective use of EDX in the ICU. Muscle Nerve 57: 772-776, 2018.

Optimizing testing methods and collection of reference data for differentiating critical illness polyneuropathy from critical illness MYOPATHIES

INTRODUCTION

In severe acute quadriplegic myopathy in intensive care unit (ICU) patients, muscle fibers are electrically inexcitable; in critical illness polyneuropathy, the excitability remains normal. Conventional electrodiagnostic methods do not provide the means to adequately differentiate between them. In this study we aimed to further optimize the methodology for the study of critically ill ICU patients and to create a reference database in healthy controls.

METHODS

Different electrophysiologic protocols were tested to find sufficiently robust and reproducible techniques for clinical diagnostic applications.

RESULTS

Many parameters show large test-retest variability within the same healthy subject. Reference values have been collected and described as a basis for studies of weakness in critical illness.

CONCLUSIONS

Using the ratio of neCMAP/dmCMAP (response from nerve and direct muscle stimulation), refractory period, and stimulus-response curves may optimize the electrodiagnostic differentiation of patients with critical illness myopathy from those with critical illness polyneuropathy.

ICU-Acquired Weakness

Survivorship after critical illness is an increasingly important health-care concern as ICU use continues to increase while ICU mortality is decreasing. Survivors of critical illness experience marked disability and impairments in physical and cognitive function that persist for years after their initial ICU stay. Newfound impairment is associated with increased health-care costs and use, reductions in health-related quality of life, and prolonged unemployment. Weakness, critical illness neuropathy and/or myopathy, and muscle atrophy are common in patients who are critically ill, with up to 80% of patients admitted to the ICU developing some form of neuromuscular dysfunction. ICU-acquired weakness (ICUAW) is associated with longer durations of mechanical ventilation and hospitalization, along with greater functional impairment for survivors. Although there is increasing recognition of ICUAW as a clinical entity, significant knowledge gaps exist concerning identifying patients at high risk for its development and understanding its role in long-term outcomes after critical illness. This review addresses the epidemiologic and pathophysiologic aspects of ICUAW; highlights the diagnostic challenges associated with its diagnosis in patients who are critically ill; and proposes, to our knowledge, a novel strategy for identifying ICUAW.

Assessment of intensive care unit-acquired weakness in young and old mice: An E. coli septic peritonitis model

INTRODUCTION

There are few reports of in vivo muscle strength measurements in animal models of ICU-acquired weakness (ICU-AW). In this study we investigated whether the Escherichia coli (E. coli) septic peritonitis mouse model may serve as an ICU-AW model using in vivo strength measurements and myosin/actin assays, and whether development of ICU-AW is age-dependent in this model.

METHODS

Young and old mice were injected intraperitoneally with E. coli and treated with ceftriaxone. Forelimb grip strength was measured at multiple time points, and the myosin/actin ratio in muscle was determined.

RESULTS

E. coli administration was not associated with grip strength decrease, neither in young nor in old mice. In old mice, the myosin/actin ratio was lower in E. coli mice at t = 48 h and higher at t = 72 h compared with controls.

CONCLUSIONS

This E. coli septic peritonitis mouse model did not induce decreased grip strength. In its current form, it seems unsuitable as a model for ICU-AW.

The influence of weaning duration on rehabilitative outcome in early neurological rehabilitation

BACKGROUND

We investigated if longer weaning is associated with inferior rehabilitative outcome in critical illness polyneuropathy (CIP) and cerebrovascular diseases (CVD).

METHODS

We analysed retrospectively weaning protocols and medical histories of 171 tracheotomized patients with CIP and CVD. We assessed weaning durations (WD), independence in activities of daily living, as assessed by the functional independence measure (FIM), mortality rates and discharge modalities in each cohort. Weaning was performed using synchronized intermittent mandatory ventilation (SIMV) with Autoflow® and assisted spontaneous ventilation (ASV).

RESULTS

WD was significantly longer in CIP compared to CVD (p < 0.001). Despite shorter in-patient treatment and longer WD, patients with CIP acquired significantly greater gains of improvement than CVD (p = 0.015). Independent living at home was possible in 43% of patients with CIP and in 26% of CVD. Mortality was equal in both groups (13% vs. 6%, p > 0.05). Chronic obstructive pulmonary disease (COPD) showed a trend towards longer weaning durations in both entities (p = 0.06). Higher age significantly correlated with longer WD (p = 0.038, r = 0.16). Longer rehabilitation duration (RD) positively correlated with higher Delta-FIM (DFIM) in both entities (p = 0.006, r = 0.21).

CONCLUSION

Longer weaning and its partly negative influence on rehabilitative outcome can be compensated by longer in-patient rehabilitation in CIP and CVD.

Critical illness polyneuropathy and myopathy: a systematic review

Critical illness polyneuropathy and critical illness myopathy are frequent complications of severe illness that involve sensorimotor axons and skeletal muscles, respectively. Clinically, they manifest as limb and respiratory muscle weakness. Critical illness polyneuropathy/myopathy in isolation or combination increases intensive care unit morbidity via the inability or difficulty in weaning these patients off mechanical ventilation. Many patients continue to suffer from decreased exercise capacity and compromised quality of life for months to years after the acute event. Substantial progress has been made lately in the understanding of the pathophysiology of critical illness polyneuropathy and myopathy. Clinical and ancillary test results should be carefully interpreted to differentiate critical illness polyneuropathy/myopathy from similar weaknesses in this patient population. The present review is aimed at providing the latest knowledge concerning the pathophysiology of critical illness polyneuropathy/myopathy along with relevant clinical, diagnostic, differentiating, and treatment information for this debilitating neurological disease.

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

INTRODUCTION

Muscle weakness in critically ill patients after discharge varies. It is not known whether the electrophysiological distinction between critical illness myopathy (CIM) and critical illness polyneuropathy (CIP) during the early part of a patient's stay in the intensive care unit (ICU) predicts long-term prognosis.

METHODS

This was a prospective cohort study of mechanically ventilated ICU patients undergoing conventional nerve conduction studies and direct muscle stimulation in addition to neurological examination during their ICU stay and 1 year after ICU discharge.

RESULTS

Twenty-six patients (7 ICU controls, 8 CIM patients, and 11 CIM/CIP patients) were evaluated 1 year after discharge from the ICU. Eighty-eight percent (n = 7) of CIM patients recovered within 1 year compared with 55% (n = 6) of CIM/CIP patients. Thirty-six percent (n = 4) of CIM/CIP patients still needed assistance during their daily routine (P = 0.005).

CONCLUSIONS

Early electrophysiological testing predicts long-term outcome in ICU survivors. CIM has a significantly better prognosis than CIM/CIP.

Neuromuscular complications of critical illness

Patients admitted to intensive care units (ICUs) suffer from a wide range of neurological disorders. Some develop within the ICU rendering weakness and difficulty in weaning patients from ventilator support. ICUAW, or ICU acquired weakness, is a broad term that includes several more specific neuromuscular problems. After exclusion of other causes of weakness, ICUAW includes critical illness polyneuropathy (CIP), first described by Charles Bolton, critical illness myopathy (CIM), and disorders of neuromuscular junction transmission. This chapter reviews the clinical, electrophysiological, and pathological features of these conditions and provides clinicians with approaches toward diagnosing and investigating ICUAW.

Intensive care unit acquired weakness in children: Critical illness polyneuropathy and myopathy

BACKGROUND AND AIMS

Intensive care unit acquired weakness (ICUAW) is a common occurrence in patients who are critically ill. It is most often due to critical illness polyneuropathy (CIP) or to critical illness myopathy (CIM). ICUAW is increasingly being recognized partly as a consequence of improved survival in patients with severe sepsis and multi-organ failure, partly related to commonly used agents such as steroids and muscle relaxants. There have been occasional reports of CIP and CIM in children, but little is known about their prevalence or clinical impact in the pediatric population. This review summarizes the current understanding of pathophysiology, clinical presentation, diagnosis and treatment of CIP and CIM in general with special reference to published literature in the pediatric age group.

SUBJECTS AND METHODS

Studies were identified through MedLine and Embase using relevant MeSH and Key words. Both adult and pediatric studies were included.

RESULTS

ICUAW in children is a poorly described entity with unknown incidence, etiology and unclear long-term prognosis.

CONCLUSIONS

Critical illness polyneuropathy and myopathy is relatively rare, but clinically significant sequelae of multifactorial origin affecting morbidity, length of intensive care unit (ICU) stay and possibly mortality in critically ill children admitted to pediatric ICU.

"Dry" and "wet" beriberi mimicking critical illness polyneuropathy

Three cases with manifestations of right heart failure, shock, metabolic acidosis, and renal failure in varying combination were admitted with paraparesis. Nerve conduction study suggested predominantly motor and mainly axonal type of neuropathy. Rapid reversal of shock, acidosis, and multi-organ dysfunction with timely infusion of thiamine was followed by the complete neurological recovery.

Unusual presentation of Guillain-Barré syndrome following traumatic bone injuries: report of two cases

OBJECTIVE

To report two cases of Guillain-Barré syndrome (GBS) which occurred following traumatic bone injuries.

PRESENTATION AND INTERVENTION

Two patients presented with traumatic bone injuries. The first was a 47-year-old female who was admitted with fracture of both tibial bones sustained during a road traffic accident. One week after surgical fixation of the fracture, she developed areflexic weakness of all four limbs and respiratory muscle weakness. The nerve conduction study was consistent with GBS. She was administered intravenous immunoglobulins which was repeated after 2 weeks. She recovered gradually. The second patient was a 31-year-old male who was admitted with 4-days history of severe back pain which occurred when he lifted a heavy weight. He then developed ascending areflexic weakness of all four limbs and bifacial weakness. X-ray and magnetic resonance imaging of the lumbosacral spine revealed fracture of L1 and L2 vertebrae. Nerve conduction studies confirmed the diagnosis of GBS. He was given mechanical ventilatory support and was treated with intravenous immunoglobulins and later plasmapheresis. However, his condition gradually deteriorated as he developed aspiration pneumonia and sepsis with multi-organ failure and finally expired.

CONCLUSION

These cases highlight the importance of considering GBS as a differential diagnosis when patients with traumatic bone injuries develop acute neuromuscular weakness. Early diagnosis and treatment may prevent morbidity and mortality.