Acute Neuromuscular Disorders Research Articles

Neuromuscular problems of the critically Ill neonate and child

Acute neuromuscular disorders occasionally occur in the Pediatric Neurologic Intensive Care Unit. Many of these are primary disorders of the motor unit that may present acutely or exacerbate during an intercurrent illness. Additionally, acute neuromuscular disorders may develop during an acute systemic illness requiring intensive care management that predispose the child to another set of acute motor unit disorders. This chapter discusses acute neuromuscular crises in the infant, toddler, and adolescent, as well as neuromuscular disorders resulting from critical illness.

Acute neuromuscular disorders in critically ill children

Acute neuromuscular disorders are a group of neurological emergencies characterized by rapid onset of motor weakness commonly involving the respiratory and bulbar muscles. These can be acute or an exacerbation of the chronic neuromuscular disease. An accurate and timely diagnosis allows for the timely institution of specific therapies, improving long-term functional outcomes. Landry–Guillain–Barre syndrome (LGBS), acute transverse myelitis, compressive myelopathy, traumatic spinal lesions, and anterior horn cell myelitis (due to viral infections) are some of the common causes of acute motor weakness in children. LGBS is the most common among all. The diagnosis relies on clinical presentation, signs, cerebrospinal fluid analysis, electrophysiological studies, and neuroimaging of the spine. Once compressive or traumatic spinal lesions are suspected, immediate neuroimaging of the spine is essential to plan early neurosurgical intervention. Pediatric intensive care unit (PICU) admission is often required for supportive management and immunomodulation. Supportive management typically includes endotracheal intubation to protect the airway, mechanical ventilation (MV) to support breathing, monitoring, management of autonomic dysfunction, control of pain, physiotherapy, adequate nutrition, prevention of pressure sores, bladder–bowel care, psychological support, and planning of long-term care. Autonomic dysfunction can cause hemodynamic instability, arrhythmias, sudden cardiac arrest, and death, requiring close monitoring and management in PICU. Tracheostomy is often needed in children who continue to have respiratory paralysis and are predicted to require long-term term mechanical ventilation. The outcome generally depends on the primary disease and long-term care.

Stroke syndrome Z: Bilateral Symmetrical Corona Radiata strokes causing facial diplegia, anarthria, and quadriparesis mimicking an acute neuromuscular syndrome (P3-5.025)

<h3>Objective:</h3> We report a 63-year-old man with consecutive, bilateral, and symmetrical Corona Radiata infarcts within 4 weeks duration, who presented with quadriparesis in addition to acute onset anarthria, and facio-labio-glosso-pharyngo-laryngeal paralysis. To our knowledge, there are no reported cases of recurrent lacunar stroke affecting the same area in the contralateral hemisphere as seen in our case. <h3>Background:</h3> Stroke is a leading cause of death and disability in the United states and particularly in our region; western New york. Around ¼ of annual strokes are recurrent strokes. It is important to identify clinical stroke syndromes to prevent any delays in care and possible clinical deterioration associated with that delay. <h3>Design/Methods:</h3> Case report <h3>Results:</h3> A 63 year-old-male with a recent history of left corona radiata stroke with residual right-sided weakness was evaluated by the neurology team for acute onset anarthria, tongue hypotonia, difficulty with chewing, swallowing and mastication along with quadriplegia. Patient was unable to open mouth on command but was able to yawn. Brain MRI revealed an acute right corona radiata infarct, a mirror image of the recent left corona radiata infarct. Gradually, upper motor neuron signs start to appear on day 2. <h3>Conclusions:</h3> Our patient suffered an acute left corona radiation infarct, almost perfectly symmetrical to a subacute right corona radiata infarct that occurred a month prior. Due to involvement of bilateral posterior limb of internal capsule, initial presentation was acute flaccid paralysis with quadriparesis and cranial neuropathy. Initial working diagnosis was acute neuromuscular disorder rather than stroke due to clincal presentation. Loss of bilateral symmetrical neural impulse can lead to atypical presentation in acute state. <b>Disclosure:</b> Dr. Shaikh has nothing to disclose. Dr. Ouf has nothing to disclose. Dr. Van Coevering has nothing to disclose. Dr. Kandel has nothing to disclose.

Acute Neuromuscular Disorders in the Pediatric Intensive Care Unit.

The neuromuscular disorders encountered in the pediatric intensive care unit (PICU) encompass a broad spectrum of pathologies. These include acute disorders (eg, Guillain-Barre syndrome), acute-on-chronic disorders (eg, myasthenia gravis), progressive disorders (eg, muscular dystrophy), and disorders that develop in the PICU (eg, critical illness myopathy/polyneuropathy). Familiarity with the presenting features of these disorders is of paramount importance in facilitating timely diagnosis. We conducted a retrospective review of the medical records of patients admitted to the PICU or Intermediate Care Program (ICP) at a single tertiary children's hospital from 2006 to 2017 with an acute or acute-on-chronic neuromuscular disorder. We did not include patients with a known progressive neuromuscular disorder or critical illness myopathy/polyneuropathy. Twenty-four patients were admitted to the PICU/ICP with acute or acute-on-chronic neuromuscular disorders. Diagnosis and indication for ICU/ICP admission were Guillain-Barre syndrome (n = 6; respiratory failure: 3, respiratory monitoring: 2, autonomic instability: 1), myasthenia gravis (n = 5; airway clearance: 3, respiratory failure: 2), acute flaccid myelitis (n = 3; respiratory failure: 2, respiratory monitoring: 1), periodic paralysis (n = 3; intravenous potassium replacement), rhabdomyolysis (n = 3; monitoring for electrolyte derangements), infant botulism (n = 2; respiratory failure), chronic demyelinating polyneuropathy (n = 1; respiratory failure), and congenital myasthenic syndrome (n = 1; apnea). No patients were admitted to the PICU/ICP with a diagnosis of tick paralysis, acute intermittent porphyria, or inflammatory myopathy. Although acute and acute-on-chronic neuromuscular disorders are encountered relatively rarely in the PICU, familiarity with the presenting features of these disorders is important in facilitating timely diagnosis. This, in turn, enables the institution of effective management strategies, thereby avoiding complications associated with diagnostic delays.

Electrophysiological findings in immune checkpoint inhibitor-related peripheral neuropathy

ObjectiveTo report the electrodiagnostic features of immune checkpoint inhibitor (ICI)-related neuropathy. MethodsWe retrospectively reviewed clinical presentations and electrodiagnostic features of 23 patients studied after receiving immune checkpoint inhibitors (ICIs). The presentations for electrodiagnostic evaluation included an acute neuropathy or neuromuscular junction disorder. We applied established electrodiagnostic criteria for polyneuropathy and acute demyelinating neuropathy. ResultsWe identified acute demyelinating neuropathy (13 cases), axonal sensory motor neuropathy (5), pure sensory neuropathy (4) and mononeuropathy (1). 13 patients had acute demyelinating neuropathy confirmed by demonstrating demyelination in 2 or more nerves; 3 additional patients had demyelination in only one nerve. Analysis of motor nerve conduction parameters revealed demyelination involving median and ulnar nerve distal motor latencies as well as median, ulnar and peroneal nerve conduction velocities. Conduction block was found in median, ulnar and peroneal nerves. The remaining one-third patients without demyelination had acute painful axonal neuropathy. Coexisting myopathic changes (6) and neuromuscular junction dysfunction (4) were also identified. ConclusionsOur findings suggest that, while immune-mediated motor nerve demyelination is the primary underlying mechanism of ICI-related neuropathy, axonal painful neuropathy can also be an important presentation. Early recognition and effective intervention may reduce morbidity and permanent disability. SignificanceElectrophysiological studies might be useful in the evaluation of ICI-related neuropathy.

Peripheral nerve conduction abnormalities precede morphological alterations in an experimental rat model of sepsis.

The pathological mechanisms of critical illness polyneuropathy (CIP), an acute neuromuscular disorder, remain unknown. In this study, we evaluated nerve and vascular properties that might account for electrophysiological abnormalities, including reduced nerve conduction amplitude, in the early phase of CIP. Rats were administered intravenous saline (C-group; n=31) or lipopolysaccharide (3mg/kg/day; L-group; n=30) for 48h. Subsequently, tracheotomy was performed and sciatic nerves exposed bilaterally. A catheter was inserted into the left internal carotid artery to measure the mean arterial pressure (MAP). Nerve conduction velocity (NCV), nerve blood flow (NBF), evoked amplitudes, chronaxie, rheobase, and the absolute refractory period (ARP) were measured from the sciatic nerves. Degeneration, myelination, and neutrophil infiltration were examined in the sciatic nerves using histology and electron microscopy. The NBF (C-group 25±3ml/100g/min, L-group 13±3ml/100g/min, p<0.001) was lower in the L-group, but the MAP was similar between groups (C-group 119±17mmHg, L-group 115±18mmHg, p=0.773). LPS also caused a severe reduction in amplitude (C-group 0.9±0.2mV, L-group 0.2±0.1mV, p<0.001), while latency and NCV were not affected. Of note, response amplitudes partially recovered with an increase in stimulus intensity. LPS treatment increased the rheobase and decreased the chronaxie (rheobase: C vs L-group; 0.35±0.07 vs 1.29±0.66mA, p<0.001; chronaxie 171±24 vs 42±20µs, p<0.001), while ARP was unchanged. No primary axonal degeneration or inflammatory infiltration was observed. Our findings suggest that primary electrophysiological deterioration is due to threshold alterations rather than morphological alterations after 48h of LPS treatment.

Arthrodesis of the Thumb Interphalangeal Joint and Finger Distal Interphalangeal Joints With a Headless Compression Screw

To study the results of using a small, headless compression screw (AcuTwist) for thumb interphalangeal (IP) joint and finger distal interphalangeal (DIP) joint arthrodeses. Between November 2007 and January 2012, 48 primary arthrodeses of the thumb IP joint or DIP joint in the other digits were performed in 29 consecutive patients with AcuTwist devices. Indications for arthrodesis included 19 cases of osteoarthritis in 25 fingers, 3 cases of lupus in 9 fingers, 2 cases of post-traumatic osteoarthritis in 2 fingers, and 1 case and finger each of acute trauma, neuromuscular disorder, postinfectious osteoarthritis, boutonniere deformity, and Dupuytren contracture. Charts were reviewed for clinical data, and radiographs were assessed for alignment and healing. Age averaged 59 years and follow-up averaged 12 months (range, 2-50 mo). Union occurred in 43 out of 46 fingers (94%). There were no cases of nail deformity, wound complications, tip hypersensitivity, or clinically notable malalignment. Three arthrodeses failed to fuse, including 2 asymptomatic nonunions and 1 fixation loss requiring revision with autograft. The complication rate was 9%. Distal digital joint arthrodesis with the AcuTwist resulted in a fusion rate of 94% with a complication rate of 9%. Our rate of fusion compares favorably with prior series using other methods of fixation. Therapeutic IV.

Comparison of melatonin and oxytocin in the prevention of critical illness polyneuropathy in rats with experimentally induced sepsis

BackgroundCritical illness polyneuropathy is an acute neuromuscular disorder of critically ill patients and is characterized by limb and respiratory muscle weakness. The purpose of the study was to evaluate the neuroprotective effects of melatonin (MEL) and oxytocin (OT) on the early stage of sepsis by recording compound muscle action potentials and measuring plasma tumor necrosis factor (TNF)-α levels, lipid peroxidation (malondialdehyde; MDA), and total antioxidant capacity. Materials and methodsOne hundred adult male Sprague-Dawley rats were included in the study. The cecal ligation and puncture (CLP) procedure was performed to induce the sepsis model. MEL (10, 20, and 40 mg/kg), OT (0.4, 0.8, and 1.6 mg/kg), and a combination of MEL (20 mg/kg) and OT (0.8 mg/kg) were administered intraperitoneally in the first hour of surgery. Electromyography (EMG) studies were achieved 24 h after CLP surgery and then blood samples were collected for biochemical measurements. ResultsEMG findings revealed that compound muscle action potential amplitude was significantly decreased and distal latency was prolonged in the CLP group compared with the sham group (P < 0.05 and P < 0.0005). Moreover, the animals that received CLP surgery showed significantly higher TNF-α and MDA levels and lower total antioxidant capacity values than the sham group. The administration of MEL and OT to rats significantly abolished the EMG alterations and suppressed oxidative stress and TNF-α release in CLP-induced rats. ConclusionsThe inflammatory processes and imbalance in oxidative/antioxidative status play important roles in the pathogenesis of critical illness polyneuropathy. We suggest that both oxytocin and melatonin may have beneficial effects against sepsis-induced polyneuropathy in critical illness.

Frequency of cyclic lumbar loading is a risk factor for cumulative trauma disorder

Epidemiologic studies indicate that repetitive (cyclic) occupational activities lead to a cumulative trauma disorder (CTD), and the frequency or velocity of the movement is one of the risk factors. Experimental neurophysiological evidence to confirm the epidemiology is not available. The response of the multifidus muscles to cyclic loading in anterior lumbar flexion-extension was assessed to test the hypothesis that high-frequency loading may induce an acute neuromuscular disorder leading to CTD. Two groups of feline preparations were subjected to cyclic loading with a peak of 20 N: one at 0.25 HZ and the second at 0.5 HZ, with an equal number of cycles. Electromyogram (EMG), lumbar displacement and load were recorded throughout the loading periods and during single-cycle tests over a 7-hour rest period following the load-rest sessions. A model was developed to quantify the creep and neuromuscular responses, and analysis of variance (ANOVA) was applied to assess significance of the results. The group exposed to 0.5 HZ exhibited spontaneous spasms followed by sustained spasms during the loading periods. During the 7-hour recovery period, a significant (P < 0.001) delayed hyperexcitability as well as sustained spasms of the multifidi were present in the last 5 hours, confirming a significant (P < 0.024 to P < 0.042) acute neuromuscular disorder. High-frequency cyclic loading of the lumbar spine may trigger a severe acute neuromuscular disorder, as evidenced by the sustained spasms and delayed hyperexcitability, and should be considered as a risk factor. We suggest that workers avoid high-frequency exposure to cyclic activity in order to prevent the development of cumulative trauma disorder.

Ligaments: A source of musculoskeletal disorders

The mechanical and neurological properties of ligaments are reviewed and updated with recent development from the perspective which evaluates their role as a source of neuromusculoskeletal disorders resulting from exposure to sports and occupational activities. Creep, tension-relaxation, hysteresis, sensitivity to strain rate and strain/load frequency were shown to result not only in mechanical functional degradation but also in the development of sensory-motor disorders with short- and long-term implication on function and disability. The recently exposed relationships between collagen fibers, applied mechanical stimuli, tissue micro-damage, acute and chronic inflammation and neuromuscular disorders are delineated with special reference to sports and occupational stressors such as load duration, rest duration, work/rest ratio, number of repetitions of activity and velocity of movement.

Pressure support ventilation attenuates ventilator-induced protein modifications in the diaphragm

Common medical conditions that require mechanical ventilation include chronic obstructive lung disease, acute lung injury, sepsis, heart failure, drug overdose, neuromuscular disorders, and surgery. Although mechanical ventilation can be a life saving measure, prolonged mechanical ventilation can also present clinical problems. Indeed, numerous well-controlled animal studies have demonstrated that prolonged mechanical ventilation results in diaphragmatic weakness due to both atrophy and contractile dysfunction. Importantly, a recent clinical investigation has confirmed that prolonged mechanical ventilation results in atrophy of the human diaphragm. This mechanical ventilation-induced diaphragmatic weakness is important because the most frequent cause of weaning difficulty is respiratory muscle failure due to inspiratory muscle weakness and/or a decline in inspiratory muscle endurance. Therefore, developing methods to protect against mechanical ventilation-induced diaphragmatic weakness is important.

Short rest between cyclic flexion periods is a risk factor for a lumbar disorder

The epidemiology identifies cyclic lumbar loading as a risk factor for cumulative trauma disorder. Experimental biomechanical and physiological confirmation is lacking. The objective of this study was to asses the impact of different rest durations applied between periods of cyclic loading on the development of an acute lumbar disorder which, if continued to be subjected to loading, may develop into a cumulative disorder. Three groups of in vivo feline preparations were subjected to six sequential 10 min loading periods of cyclic lumbar flexion at 40 N with a frequency of 0.25 Hz applied to the L-4/5 level. The rest durations varied from 5 min in the first group, to 10 min in the second and to 20 min in the third. Reflexive EMG from the multifidi and lumbar displacement were used to identify significant (P<0.001) effects of time and rest duration for post-load EMG and displacement. Single-cycle test were performed hourly for 7 h post-loading to assess recovery. A model developed earlier was applied to represent the experimental data. The groups allowed 5 and 10 min rest exhibited an acute neuromuscular disorder expressed by a significant (P<0.001) delayed hyperexcitability 2-3 h into the 7 h recovery period with the intensity of the hyperexcitability significantly higher (P<0.001) for the group allowed only 5 min rest. The group allowed 20 min rest had a slow, uneventful recovery, free of delayed hyperexcitability. Occupational and sports activities requiring repetitive (cyclic) loading of the lumbar spine may be a risk factor for the development of a cumulative lumbar disorder and may require sufficient rest, as much as twice as long as the loading period, for prevention. Comparison to similar data for static lumbar loading shows that cyclic loading is more deleterious than static loading, requiring more rest to offset the negative effect of the repeated acts of stretch.

Cyclic Load Magnitude is a Risk Factor for a Cumulative Lower Back Disorder

Epidemiological data suggest that high loads lifted by workers engaged in static and cyclic daily activities may be a risk factor for low back disorder. Our previous research provided physiological and biomechanical validation of the epidemiological data for static load conditions. The objective of this report was to provide physiological and biomechanical experimental validation to the epidemiological data in cyclic (repetitive) load conditions. Three groups of in vivo feline models were subjected to 3 cyclic load levels in a series of 6 periods of 10 minutes of work spaced by 10 minutes of rest followed by 7 hours of rest. Multifidus electromyography (EMG) and lumbar displacement were statistically analyzed after processing. Delayed muscular hyperexcitability was observed only in moderate (40 N) and high (60 N) loads (P<0.0001) but was absent in low (20 N) loads. The magnitude of the delayed hyperexcitability was found to be higher (P<0.0001) in the high (60 N) loads compared with the moderate (40 N) loads. Exposure to moderate and high loads in cyclic (repetitive) work results in an acute neuromuscular disorder indicative of soft tissue inflammation that may become chronic with further exposure.

Critical illness polyneuropathy. Regression following cardiac operation

Critical illness polyneuropathy is an acute neuromuscular disorder of severely ill patients that may also occur in complicated postoperative heart surgery course. This case report should make this disease known also as a preoperative condition that may regress following a successful cardiac operation.

Sensory – Motor control of ligaments and associated neuromuscular disorders

The ligaments were considered, over several centuries, as the major restraints of the joints, keeping the associated bones in position and preventing instability, e.g. their separation from each other and/or mal-alignment. This project, conducted over 25 years, presents the following hypothesis: 1. Ligaments are also major sensory organs, capable of monitoring relevant kinesthetic and proprioceptive data. 2. Excitatory and inhibitory reflex arcs from sensory organs within the ligaments recruit/de-recruit the musculature to participate in maintaining joint stability as needed by the movement type performed. 3. The synergy of the ligament and associated musculature allocates prominent role for muscles in maintaining joint stability. 4. The viscoelastic properties of ligaments and their classical responses to static and cyclic loads or movements such as creep, tension–relaxation, hysteresis and strain rate dependence decreases their effectiveness as joint restraint and stabilizers and as sensory organs and exposes the joint to injury. 5. Long-term exposure of ligaments to static or cyclic loads/movements in a certain dose-duration paradigms consisting of high loads, long loading duration, high number of load repetitions, high frequency or rate of loading and short rest periods develops acute inflammatory responses which require long rest periods to resolve. These inflammatory responses are associated with a temporary (acute) neuromuscular disorder and during such period high exposure to injury is present. 6. Continued exposure of an inflamed ligament to static or cyclic load may result in a chronic inflammation and the associated chronic neuromuscular disorder known as cumulative trauma disorder (CTD). 7. The knowledge gained from basic and applied research on the sensory – motor function of ligaments can be used as infrastructure for translational research; mostly for the development of “smart orthotic” systems for ligament deficient patients. Three such “smart orthosis”, for the knee and lumbar spine are described. 8. The knowledge gained from the basic and applied research manifests in new physiotherapy modalities for ligament deficient patients. Ligaments, therefore, are important structures with significant impact on motor control and a strong influence on the quality of movement, safety/stability of the joint and potential disorders that impact the safety and health of workers and athletes.

High‐repetition cyclic loading is a risk factor for a lumbar disorder

Epidemiological data suggest that prolonged exposure to cyclic lumbar flexion elicits a chronic neuromuscular disorder and disability in workers. This study provides a physiological and biomechanical assessment of various repetitions of cyclic lumbar flexion sessions as a risk factor for development of an acute neuromuscular disorder. An in vivo feline model was subjected to 10 minutes of cyclic (0.25-HZ) loading, followed by a 10-minute rest period, repeated three times in one experimental group, six times in a second group, and nine times in the third group, followed by rest for 7 hours. Displacement of the lumbar viscoelastic tissue and reflex electromyographic (EMG) activity from the lumbar multifidus muscle were monitored. Creep developed and accumulated during each load/rest period and partially recovered during the subsequent rest. Loading periods were characterized by a decrease in reflex EMG activity with superimposed spasms. In the 7-hour recovery period, initial hyperexcitability was present in all groups, whereas only the six- and nine-repetition groups displayed significant delayed hyperexcitability, indicating the presence of acute inflammation. The mathematical model developed fit the data reasonably well, as the R2 values were generally near 0.90. It was concluded that the resulting delayed muscular hyperexcitability constitutes an acute neuromuscular disorder associated with exposure to many repetitions of cyclic lumbar flexion. The acute disorder can become chronic if not allowed sufficient rest to resolve itself. Workers engaged in cyclic lumbar flexion (e.g., loading/unloading, assembly workers) should avoid long-term exposure in order to prevent the development of a chronic neuromuscular condition known as cumulative trauma disorder.

Work to rest durations ratios exceeding unity are a risk factor for low back disorder; a feline model

Low back disorders are prominent among the work force engaged in static anterior flexion during the workday. As a continuing part of a long-term research aimed to identify the biomechanical and physiological processes and corresponding risk factors leading to such cumulative trauma disorder (CTD), we ventured to assess the effect of rest and the work-to-rest duration ratios that may prevent CTD. Three groups of the feline model were subjected to three load/rest paradigms: two 30 min loading periods spaced by 10 min rest in Group I, two 30 min loading period spaced by 30 min rest in Group II and one 60 min loading period for Group III. The cumulative loading duration in the three groups was 60 min. Each of the groups were allowed 7 h of rest while monitoring EMG and lumbar viscoelastic tissue creep each hour. The results demonstrate that for two 30 min load periods with a 30 min in between rest, an acute neuromuscular disorder was not present whereas for two 30 min loading with a 10 min rest it was. Similarly, for a 60 min loading with long-term rest, the disorder was present. Post hoc Fisher analysis demonstrated significant differences in the delayed hyperexcitability between the first and second group ( P < 0.0001) and the third and second ( P < 0.0001) group. Statistical difference in the displacement data of the three groups was not present. ANOVA showed a significant effect of time post-loading ( P < 0.0001 and different rest durations ( P < 0.0001) on the EMG data during the 7 h recovery. The new data allow us to conclude that a work-to-rest duration ratio of 1:1 can prevent the development of CTD as long as the work periods are not too long (<60 min). Longer static flexion durations do not respond favorably to rest even if it is of equal or longer duration. It is suggested that appropriate durations of rest may be a viable tool to avert CTD in a certain range whereas long static flexion durations should be avoided at all cost.

Ligaments: a source of work-related musculoskeletal disorders

The mechanical and neurological properties of ligaments are reviewed and updated with recent development from the perspective which evaluates their role as a source of neuromusculoskeletal disorders resulting from exposure to occupational activities. Creep, tension-relaxation, hysteresis, sensitivity to strain rate and strain/load frequency were shown to result not only in mechanical functional degradation but also in the development of sensory-motor disorders with short- and long-term implication on function and disability. The recently exposed relationships between collagen fibers, applied mechanical stimuli, tissue microdamage, acute and chronic inflammation and neuromuscular disorders is delineated with special reference to occupational stressors.

Muscle Edema in MR Imaging of Neuromuscular Diseases

Muscle edema has been described as a typical finding on MR images in acute neuromuscular disorders, predominantly in acute inflammatory myopathies, but also in neuro- and myopathies. The purpose of this study was to examine the frequency of muscle edema and the diagnostic usefulness of Gd-DTPA in neuromuscular diseases. 144 consecutive patients with various generalized neuromuscular diseases were examined by MR imaging. Areas of high signal intensity, relative to normal muscle, were seen in 36% of T2-weighted images, whereas the corresponding T1-weighted images showed normal or lower signal intensities. These edema-like abnormalities--enlargement of the extracellular fluid space--were found more often in inflammatory and metabolic myopathies, but were also seen in degenerative myopathies. Contrast-enhanced T1-weighted images in 25 patients were not more sensitive than plain T2-weighted images.

Acute Neuromuscular Disorders

Acute Neuromuscular Disorders