1,721,034 research outputs found
Velocity recovery cycles of human muscle action potentials and their sensitivity to ischemia
No full textThis study was undertaken to test whether recovery cycle measurements can provide useful information about the membrane potential of human muscle fibers. Multifiber responses to direct muscle stimulation through needle electrodes were recorded from the brachioradialis of healthy volunteers, and the latency changes measured as conditioning stimuli were applied at interstimulus intervals of 2-1000 ms. In all subjects, the relative refractory period (RRP), which lasted 3.27 +/- 0.45 ms (mean +/- SD, n = 12), was followed by a phase of supernormality, in which the velocity increased by 9.3 +/- 3.4% at 6.1 +/- 1.3 ms, and recovered over 1 s. A broad hump of additional supernormality was seen at around 100 ms. Extra conditioning stimuli had little effect on the early supernormality but increased the later component. The two phases of supernormality resembled early and late afterpotentials, attributable respectively to the passive decay of membrane charge and potassium accumulation in the t-tubules. Five minutes of ischemia progressively prolonged the RRP and reduced supernormality, confirming that these parameters are sensitive to membrane depolarization. Velocity recovery cycles may provide useful information about altered muscle membrane potential and t-tubule function in muscle disease. Muscle Nerve, 2008
Critical Illness Myopathy: Glucocorticoids revisited?
Full text linkOver the past decades, survival rates of critical illness have constantly increased. As a consequence, the incidences of important complications of intensive care unit (ICU) treatment become more and more prevalent. Critical illness myopathy (CIM) belongs to one of the most frequent neuromuscular complications and its presence is associated with prolonged need for mechanical ventilation and ICU stay, increased morbidity and mortality 1,2. High-dose glucocorticoid (GC) treatment was early after the initial description of CIM postulated to be a major triggering factor for the development of the disease. In the current issue of Acta Physiologica, Akkad et al. investigate the effects of two GC drugs (prednisolone and a new dissociative GC termed vamorolone) on CIM development3. This article is protected by copyright. All rights reserved
Critical Illness Myopathy: Diagnostic Approach and Resulting Therapeutic Implications.
Full text linkPurpose of review
Critical illness myopathy (CIM) is a common neuro-muscular complication of intensive care treatment associated with increased morbidity and mortality. The current guidelines for diagnosis include clinical and electrophysiological criteria as well as a muscle biopsy, and allow diagnosis only at an advanced stage of the disease. To date, there is no treatment for CIM available, apart from symptomatic and rehabilitative interventions. In this review, we discuss different diagnostic approaches and describe new treatment possibilities for CIM.
Recent findings
Of the diagnostic approaches evaluated, a new electrophysiological technique for measuring muscle excitability has the greatest potential to allow earlier diagnosis of CIM than the current guidelines do and thereby may facilitate the conduction of future pathophysiological and therapeutic studies. Although clinical trials are still lacking, in animal models, BGP-15, vamorolone, and ruxolitinib have been shown to have anti-inflammatory effects, to reduce muscle wasting and to improve muscle function and survival.
Summary
In recent years, promising methods for early and confirmatory diagnosis of CIM have been developed, but still need validation. Experimental studies on novel pharmacological interventions show promising results in terms of preventive CIM treatments, but future clinical studies will be needed to study the effectiveness and safety of these drugs
Dysfunction of respiratory muscles in critically ill patients on the intensive care unit.
Full text linkMuscular weakness and muscle wasting may often be observed in critically ill patients on intensive care units (ICUs) and may present as failure to wean from mechanical ventilation. Importantly, mounting data demonstrate that mechanical ventilation itself may induce progressive dysfunction of the main respiratory muscle, i.e. the diaphragm. The respective condition was termed 'ventilator-induced diaphragmatic dysfunction' (VIDD) and should be distinguished from peripheral muscular weakness as observed in 'ICU-acquired weakness (ICU-AW)'. Interestingly, VIDD and ICU-AW may often be observed in critically ill patients with, e.g. severe sepsis or septic shock, and recent data demonstrate that the pathophysiology of these conditions may overlap. VIDD may mainly be characterized on a histopathological level as disuse muscular atrophy, and data demonstrate increased proteolysis and decreased protein synthesis as important underlying pathomechanisms. However, atrophy alone does not explain the observed loss of muscular force. When, e.g. isolated muscle strips are examined and force is normalized for cross-sectional fibre area, the loss is disproportionally larger than would be expected by atrophy alone. Nevertheless, although the exact molecular pathways for the induction of proteolytic systems remain incompletely understood, data now suggest that VIDD may also be triggered by mechanisms including decreased diaphragmatic blood flow or increased oxidative stress. Here we provide a concise review on the available literature on respiratory muscle weakness and VIDD in the critically ill. Potential underlying pathomechanisms will be discussed before the background of current diagnostic options. Furthermore, we will elucidate and speculate on potential novel future therapeutic avenues
Improvement of non-paraneoplastic voltage-gated potassium channel antibody-associated limbic encephalitis without immunosuppressive therapy
No full textWe describe a 61-year-old patient with clinical evidence of limbic encephalitis who improved with anticonvulsant treatment only, that is, without the use of immunosuppressive agents. Three years following occurrence of anosmia, increasing memory deficits, and emotional disturbances, he presented with new-onset temporal lobe epilepsy, with antibodies binding to neuronal voltage-gated potassium channels and bitemporal hypometabolism on FDG-PET scan; the MRI scan was normal. This is most likely a case of spontaneous remission, illustrating that immunosuppressive therapy might be suspended in milder courses of limbic encephalitis. It remains open whether treatment with anticonvulsant drugs played an additional beneficiary role through the direct suppression of seizures or, additionally, through indirect immunomodulatory side effects
Normaldruck-Hydrozephalus
Full text linkGangstörung, kognitive Defizite und Harninkontinenz sind die typischen Symptome des idiopathischen Normaldruck-Hydrozephalus. Die Inzidenz der Erkrankung nimmt mit höherem Alter zu und mit der operativen Einlage einer Liquorableitung besteht auch bei älteren Patienten eine effektive Therapieoption
Validity of multi-fiber muscle velocity recovery cycles recorded at a single site using submaximal stimuli
No full textTo examine the validity of multi-fiber muscle velocity recovery cycles (VRCs) recorded by direct muscle stimulation with submaximal stimuli
Critical Illness Myopathy.
No full textCritical illness myopathy (CIM) is a primary myopathy associated with increased mortality and morbidity, which frequently develops in severely ill patients. Several risk factors have been suggested for the development of critical illness myopathy. However, neither the exact etiology nor the underlying mechanisms are known in detail. Although for definite diagnosis muscle biopsy is needed, electrophysiological tests are crucial for the diagnosis of probable critical illness myopathy and differential diagnosis. In this review, conventional electrophysiological tests such as nerve conduction studies, needle electromyography, direct muscle stimulation, and repetitive stimulation for diagnosis of critical illness myopathy are summarized. Moreover, studies using the novel method of recording muscle velocity recovery cycles are addressed
Decompressive craniectomy plus best medical treatment versus best medical treatment alone for spontaneous severe deep supratentorial intracerebral haemorrhage: a randomised controlled clinical trial
No full textFunder:
http://dx.doi.org/10.13039/501100001711
Swiss National Science Foundatio
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