Steroid myopathy in connective tissue disease

Clinical and pathological aspects of toxic myopathies

As the most frequent cause of acquired myopathy, toxic myopathies are characterised by clinicopathological features that vary depending on the mode of action of the drugs or toxins involved. Although a large number of substances can induce myotoxicity, the main culprits are statins, alcohol, and corticosteroids. A rigorous, well-organised diagnostic approach is necessary to obtain a rapid diagnosis. For early diagnosis and management, it is important for clinicians to be aware that most toxic myopathies are potentially reversible, and the goal of treatment should be to avoid serious muscle damage.

Drug-Induced Myopathies: A Comprehensive Review and Update

Drug-induced myopathies are a common cause of muscle pain, and the range of drugs that can cause muscle side effects is constantly expanding. In this article, the authors comprehensively discuss the diagnostic and therapeutic process in patients with myalgia, and present the spectrum of drug-induced myopathies. The review provides a detailed analysis of the literature on the incidence of myopathy during treatment with hypolipemic drugs, beta-blockers, amiodarone, colchicine, glucocorticosteroids, antimalarials, cyclosporine, zidovudine, and checkpoint inhibitors, a group of drugs increasingly used in the treatment of malignancies. The article considers the clinical course of the different types of myopathies, their pathogenesis, histopathological features, and treatment methods of these disorders. The aim of this paper is to gather from the latest available literature up-to-date information on the course, pathophysiology, and therapeutic options of drug-induced myopathies, to systematize the knowledge of drug-induced myopathies and to draw the attention of internists to the fact that these clinical issues are an important therapeutic problem.

Frailty and muscle weakness in elderly patients with asthma and their association with cumulative lifetime oral corticosteroid exposure

BACKGROUND

Frailty is a geriatric syndrome of age-related physiological decline, which is associated with higher mortality and decreased healthy life expectancy, and muscle weakness is one of the presentations of frailty. We investigated an association between lifetime oral corticosteroid (OCS) exposure with frailty and muscle weakness among elderly patients with asthma.

METHODS

We studied 203 consecutive elderly outpatients with asthma aged ≥60 years old. They were classified into three groups according to their cumulative lifetime OCS dose (lifetime non-users, lower-dose users, and higher-dose users), which was retrospectively estimated from the response to a structured questionnaire. The prevalence of frailty determined by the Kihon Checklist was compared between the three groups. Hand-grip strength, and lean mass index were also measured as markers of muscle strength.

RESULTS

Thirty-seven percent of the patients studied were considered frail. Higher cumulative lifetime OCS exposure was associated with a significantly higher prevalence of frailty (33% in lifetime non-users, 59% in lower-dose users, and 68% in higher-dose users; P for trend <0.005). This was also associated with lower hand-grip strength in both sexes (P for trend; 0.012 in men, and 0.020 in women), and lower lean mass index in men (P for trend 0.002). However, current doses of OCS were not significantly associated with these outcomes.

CONCLUSIONS

Cumulative lifetime OCS exposure was associated with a higher prevalence of frailty and muscle weakness. These findings emphasize the importance of minimizing lifetime OCS exposure for the prolongation of healthy life expectancy in patients with asthma.

Therapieoptionen und outcome bei idiopathischen entzündlichen Muskelerkrankungen

Die idiopathischen entzündlichen Muskelerkrankungen (IIM) sind eine sehr heterogene Gruppe, die sich immer besser differenzieren lässt. Damit eröffnen sich mehr Möglichkeiten für gezieltere Therapien, die zum einen auf die Veränderung pathogenetischer Faktoren gerichtet sind. Zum anderen sollen sie Krankheitsaktivität vermindern, Muskelaufbau fördern, Organschäden verhindern und Lebensqualität verbessern.

Die folgende Übersichtsarbeit fasst die vorhandenen Daten zu bereits angewandten Behandlungen in der Praxis zusammen und gibt einen Ausblick auf zukünftige Alternativen.

Für die Polymyositis (PM) und Dermatomyositis (DM) sind Glukokortikoide weiter unverzichtbarer Therapiebestandteil. Eine frühe Kombination mit konventionellen DMARDs hat sich durchgesetzt. Die ProDerm- Studie stellt für die Immunglobulintherapie in der Praxis eine gute Basis dar. Rituximab (RTX) löst Cyclophosphamid (CYC) bei schweren Verlaufsformen immer mehr ab.

Für Abatacept, Jak-Kinase-Hemmer, Apremilast, Sifalimumab und Lenabasum müssen vielversprechende erste Ergebnisse durch weiter Studien untermauert werden. Anspruchsvoll ist die Behandlung bei extramuskulärer Beteiligung. Von großem Interesse ist der zukünftige Stellenwert von Nintedanib bei der interstitiellen Lungenerkrankung im Rahmen einer Myositis (IIM-ILD).

Die Therapie der Einschlusskörperchen- Myositis (IBM) ist immer noch eine große Herausforderung. Zahlreiche Studien haben bisher nicht überzeugend zu einer Besserung der Prognose führen können. Spätestens bei therapierefraktärem Verlauf sollte an eine Malignom- assoziierte Myositis gedacht werden. Gelegentlich verbirgt sich auch eine hereditäre Myopathie hinter einer, zum Beispiel durch einen Infekt oder Überlastung getriggerten, Myositis.

Komplikationen im Verlauf, wie Dysphagie, Infektionen, Myokardbeteiligung stellen keine Seltenheit dar. Häufig besteht Multimorbidität. Eine interdisziplinäre Zusammenarbeit in einem kompetenten Team, in dem erfahrene Physio-, Ergo- und Psychotherapeuten fester Bestandteil sind, ist unabdingbar für eine erfolgreiche Begleitung dieser Patienten.

Hydroxychloroquine-Induced Toxic Myopathy Causing Diaphragmatic Weakness and Lung Collapse Requiring Prolonged Mechanical Ventilation

A 42-year-old woman with juvenile idiopathic arthritis was treated with anakinra, corticosteroids, and hydroxychloroquine when she developed chronic hypoxic respiratory myopathy. She was admitted to the intensive care unit for acute hypercapnic respiratory failure and required prolonged intubation, subsequent tracheostomy, and long-term ventilatory support due to multiple failed spontaneous breathing trials after discontinuation of anakinra and steroids. Muscle biopsy revealed type II fiber atrophy with the accumulation of autophagosomes and vacuoles presenting as curvilinear bodies, elevated MHC class I antigen expression, and infiltration by CD68+ macrophages and CD8+ T cells. Type II fiber atrophy was attributed to corticosteroid use and curvilinear bodies due to blockade of autophagy by hydroxychloroquine. After hydroxychloroquine was discontinued, the patient recovered to her prehospitalization baseline.

Effects of exercise in patients with connective tissue disease receiving high-dose glucocorticoids: A pilot prospective cohort study

PURPOSE

High doses of glucocorticoids induce skeletal muscle weakness. The aim of this study was to evaluate the effects of exercise therapy on skeletal muscle strength, mass, and exercise capacity in patients with connective tissue disease treated with high doses of glucocorticoids.

METHODS

This prospective, observational, single-center, cohort study included 35 patients aged ≥ 15 years diagnosed with connective tissue disease who received high-dose glucocorticoids and physical training. Exercise therapy, including moderate aerobic and strength training, was performed five times a week. Knee extension strength, skeletal muscle mass, anaerobic threshold, and peak oxygen consumption were measured at the beginning of exercise therapy and at discharge.

RESULTS

After 6 weeks of aerobic and strength exercises, skeletal muscle mass significantly decreased by 5.5%, right knee extension decreased by 11.6%, and left knee extension decreased by 9.7%. The anaerobic threshold and peak oxygen consumption significantly increased by 13.0% and 9.0%, respectively. The increase in glucocorticoid dose was inversely correlated with changes in knee extension strength.

CONCLUSION

In patients with connective tissue disease being treated with high-dose glucocorticoids, exercise therapy might attenuate the decrease in skeletal muscle mass and strength and increase the anaerobic threshold and peak oxygen consumption, thus moderating the side effects of high-dose glucocorticoid treatment. Trial registration The trial is registered with UMIN (University Hospital Medical Information Network), ID number UMIN000038836.

Muscle Toxicity of Drugs: When Drugs Turn Physiology into Pathophysiology

Drugs are prescribed to manage or prevent symptoms and diseases, but may sometimes cause unexpected toxicity to muscles. The symptomatology and clinical manifestations of the myotoxic reaction can vary significantly between drugs and between patients on the same drug. This poses a challenge on how to recognize and prevent the occurrence of drug-induced muscle toxicity. The key to appropriate management of myotoxicity is prompt recognition that symptoms of patients may be drug related and to be aware that inter-individual differences in susceptibility to drug-induced toxicity exist. The most prevalent and well-documented drug class with unintended myotoxicity are the statins, but even today new classes of drugs with unintended myotoxicity are being discovered. This review will start off by explaining the principles of drug-induced myotoxicity and the different terminologies used to distinguish between grades of toxicity. The main part of the review will focus on the most important pathogenic mechanisms by which drugs can cause muscle toxicity, which will be exemplified by drugs with high risk of muscle toxicity. This will be done by providing information on key clinical and laboratory aspects, muscle electromyography patterns and biopsy results, and pathological mechanism and management for a specific drug from each pathogenic classification. In addition, rather new classes of drugs with unintended myotoxicity will be highlighted. Furthermore, we will explain why it is so difficult to diagnose drug-induced myotoxicity, and which tests can be used as a diagnostic aid. Lastly, a brief description will be given of how to manage and treat drug-induced myotoxicity.

Quantitative ultrasound of muscle can detect corticosteroid effects

OBJECTIVES

In this study, we sought to determine whether quantitative ultrasound (QUS) could detect the impact of corticosteroids on muscle in the absence of frank weakness.

METHODS

QUS was performed on selected limb muscles of 20 brain tumor patients treated with dexamethasone and 30 healthy controls. Echointensity was quantified using gray scale level (GSL) analysis and compared between groups; correlation to corticosteroid exposure was also performed.

RESULTS

Average 4-muscle GSL (±standard deviation) was greater in patients compared to controls (35.5 ± 5.61 arbitrary units (AU) versus 30.4 ± 4.17 AU, p = 0.001), with the greatest differences in tibialis anterior. Average muscle GSL also correlated to length of corticosteroid therapy (rho = 0.52, p = 0.01).

CONCLUSIONS

These findings suggest that QUS may be able to quantify skeletal muscle alterations associated with chronic corticosteroid use. Further study of this approach is warranted.

SIGNIFICANCE

The findings of this study may provide a tool to evaluate corticosteroid myopathy.

Neurologic complications of kidney transplantation

Renal transplant is the most common organ transplant in the United States, and the frequency of kidney transplants continues to rise as transplant offers improved survival and quality of life compared to dialysis. However, complications are not uncommon and patients frequently encounter issues requiring hospitalization, especially in the first year postoperatively. Complications that arise are typically related to surgical complications, immunosuppressive medications, or infection due to immunosuppression. Neurological complications are fairly common post-operatively, and are associated with increased morbidity and mortality in this population. This review discusses the most common etiologies of neurological complications after kidney transplant, including infection, malignancy, medication related, acute neuropathy, and other neurological pathology.

Treatment consensus for management of polymyositis and dermatomyositis among rheumatologists, neurologists and dermatologists

Although rheumatologists, neurologists and dermatologists see patients with polymyositis (PM) and dermatomyositis (DM), their management appears to vary depending on the physician's specialty. The aim of the present study was to establish the treatment consensus among specialists of the three fields to standardize the patient care. We formed a research team supported by a grant from the Ministry of Health, Labor and Welfare, Japan. Clinical questions (CQ) on the management of PM and DM were raised. A published work search on CQ was performed primarily using PubMed. Using the nominal group technique, qualified studies and results in the published work were evaluated and discussed to reach consensus recommendations. They were sent out to the Japan College of Rheumatology, Japanese Society of Neurology and Japanese Dermatological Association for their approval. We reached a consensus in 23 CQ and made recommendations and a decision tree for management was proposed. They were officially approved by the three scientific societies. In conclusion, a multidisciplinary treatment consensus for the management of PM and DM was established for the first time.

Acute steroid myopathy: a highly overlooked entity

BACKGROUND

Myopathy in patients being treated with corticosteroids is known primarily among chronically treated patients or in critically ill and mechanically ventilated patients receiving corticosteroids, often in high doses.

AIM

To highlight the entity of acute, early onset corticosteroid-treatment-associated myopathy and its characteristics.

DESIGN AND METHODS

Reporting our experience with four patients and reviewing all published reports of myopathy developing ≤14 days of initiating corticosteroid-treatment.

RESULTS

Acute corticosteroid myopathy (ASM) exists, though the syndrome appears to be rare. It is characterized by unpredictability and heterogeneity, sometimes developing within 1-3 days, after a single dose, which may not be high and administered by varied routes. Proximal limb muscle weakness is the most common form, but distal limb, bulbar and respiratory muscles may be involved. Steroid cessation often leads to improvement/resolution, but irreversibility may occur.

CONCLUSIONS

A high index of suspicion for the possibility of ASM is necessary to ensure drug discontinuation and recovery. This is particularly true since the entity is not widely recognized and its symptoms are often erroneously interpreted as due to the patient's underlying disease.

Change in muscle volume after steroid therapy in patients with myositis assessed using cross-sectional computed tomography

Background

Steroid therapy, a key therapy for inflammatory, allergic, and immunological disorders, is often associated with steroid myopathy as one of the side effects. Steroid therapy is considered the first-line therapy for myositis; however, there have been no reports strictly comparing the muscle mass in patients with myositis before and after steroid therapy. Thus, it is currently unclear whether steroid therapy for such patients affects muscle volume in addition to muscle strength. We aimed to determine the change in muscle mass after steroid therapy via cross-sectional computed tomography (CT) in patients with myositis.

Methods

Data from seven patients with myositis and eight controls, who were all treated with high doses of steroids, were assessed before and after steroid therapy. Clinical factors in patients with myositis included serum muscle enzyme levels and muscular strength. The cross-sectional area of skeletal muscle and the low muscle attenuation rate at the level of the caudal end of the third lumbar vertebra were obtained using CT and measured using an image analysis program for all patients. Data were subjected to statistical analysis using several well-established statistical tests. The Wilcoxon signed-rank test was used for comparing paired data for each patient. The Mann-Whitney U test was used to compare sets of data sampled from two groups. The Spearman’s rank correlation coefficient was used for determining the correlations between two variables. Statistical significance was set at p < 0.05.

Results

Muscular strength and serum muscle enzyme levels improved following steroid therapy in patients with myositis. In both groups, the cross-sectional areas of skeletal muscles decreased (myositis group: p = 0.0156; control group: p = 0.0391) and the low muscle attenuation rate tended to increase (myositis group: p = 0.0781; control group: p = 0.0547). In the myositis group, patients with chronic obstructive pulmonary disease showed a tendency toward muscle volume loss (p = 0.0571).

Conclusion

In patients with myositis treated with steroid therapy, muscle mass decreased after steroid therapy suggesting that the improvement in muscle strength was due to factors other than a change in muscle volume. Our study suggests the importance of therapies that not only improve muscle mass but also improve the quality of muscle strength.

Iatrogenic Neuromuscular Disorders: A Review

The frequency of iatrogenic neuromuscular disorders has only recently been appreciated. Pressure palsies, especially common peroneal nerve palsies following bed rest or surgical procedures, are well recognized and easily preventable disorders. Mononeuropathies may also result from direct injuries to nerves, especially from venepuncture or attempted arterial cannulation in the axilla (O'Keefe 1980) or antecubital fossa, when the median nerve is particularly at risk. Stretch injuries to the lower cervical roots or to the lower cords of the brachial plexus may complicate sternal thoracotomy (Winer & Harrison 1982). However, most iatrogenic disorders of nerve and muscle are due to the unwanted effects of drugs used in therapeutic dosage. They are thus difficult to prevent. However, early detection is possible and this may prevent the development of severe disabilities.

Idiopathic Inflammatory Myopathies: A Review of the Classification and Impact of Pathogenesis

Idiopathic inflammatory myopathies (IIMs) are a group of autoimmune muscle diseases with significant morbidity and mortality. This review details and updates the pathogenesis and emerging importance of myositis-specific antibodies in the development of IIMs. An increase in the understanding of how these myositis-specific antibodies play a role in IIMs has led to the further categorization of IIMs from the traditional polymyositis versus dermatomyositis, to additional subcategories of IIMs such as necrotizing autoimmune myositis (NAM). The diagnosis of IIMs, including manual muscle testing, laboratory studies, and non-invasive imaging have become important in classifying IIM subtypes and for identifying disease severity. Treatment has evolved from an era where glucocorticoid therapy was the only option to a time now that includes traditional steroid-sparing agents along with immunoglobulin therapy and biologics, such as rituximab.

Dexamethasone Treatment at the Myoblast Stage Enhanced C2C12 Myocyte Differentiation

Background: Glucocorticoids induce skeletal muscle atrophy in many clinical situations; however, their hypertrophic and pro-differentiation effects on myotubes have rarely been reported. We hypothesized that dexamethasone (DEX) has a dual effect on muscle differentiation, and aimed to develop a new differentiation protocol for C2C12 cell line. Methods: Dose- and time-dependent effect of DEX on C2C12 myoblast cell line was analyzed at myoblast and myotube stage, respectively. The level of differentiation was determined by myh1, pax7, atrogin-1, and myostatin mRNA expression and fusion index. Results: After differentiation and at the myotube stage, DEX treatment has an atrophic effect. Specifically, the myotube was thinner, the expression of atrogin-1 increased, and the protein content of myosin heavy chain decreased. In contrast, when DEX treatment was performed before the onset of differentiation, we observed an increase in myotube diameter and myosin heavy chain levels, and a decrease in the expression of atrogin-1. The ratio of multinuclear myotube cells increased in the DEX treatment group. The optimal treatment concentration and time was 100 μM and 48 h, respectively. Co-treatment with 10 μM DEX and 100 nM insulin further enhanced the process of myotube differentiation. Discussion: This novel finding contributed to the explanation on the stage-specific mechanism of glucocorticoid-induced myopathy. A new formula for myoblast differentiation, containing both DEX and insulin, is proposed. Further research is required to understand the complete mechanism of DEX-induced muscle hypertrophy.

The effects of bolus supplementation of branched-chain amino acids on skeletal muscle mass, strength, and function in patients with rheumatic disorders during glucocorticoid treatment

OBJECTIVES

To test the effects of bolus supplementation of branched-chain amino acids (BCAA) on skeletal muscle mass, strength, and function in patients with rheumatic disorders taking glucocorticoid (GC).

METHODS

Patients with rheumatic disorders treated with prednisolone (≥10 mg/day) were randomized to ingest additional daily 12 g of BCAA (n = 9) or not (n = 9) for 12 weeks. At baseline, and 4, 8, and 12 weeks, they underwent bioelectrical impedance analysis, muscle strength and functional tests, and computed tomography analysis for cross-sectional area of mid-thigh muscle.

RESULTS

Disease activities of the patients were well controlled and daily GC dose was similarly reduced in both groups. Limb muscle mass was recovered in both groups. Whole-body muscle mass and muscle strength and functional mobility were increased only in BCAA (+) group. The effects of BCAA supplementation on recovering skeletal muscle mass were prominent in particular muscles including biceps femoris muscle.

CONCLUSIONS

This trial is the first-in-man clinical trial to demonstrate that BCAA supplementation might be safe and, at least in part, improve skeletal muscle mass, strength, and function in patients with rheumatic disorders treated with GC.

Role of Myofibrillar Protein Catabolism in Development of Glucocorticoid Myopathy: Aging and Functional Activity Aspects

Muscle weakness in corticosteroid myopathy is mainly the result of the destruction and atrophy of the myofibrillar compartment of fast-twitch muscle fibers. Decrease of titin and myosin, and the ratio of nebulin and MyHC in myopathic muscle, shows that these changes of contractile and elastic proteins are the result of increased catabolism of the abovementioned proteins in skeletal muscle. Slow regeneration of skeletal muscle is in good correlation with a decreased number of satellite cells under the basal lamina of muscle fibers. Aging causes a reduction of AMP-activated protein kinase (AMPK) activity as the result of the reduced function of the mitochondrial compartment. AMPK activity increases as a result of increased functional activity. Resistance exercise causes anabolic and anticatabolic effects in skeletal muscle: muscle fibers experience hypertrophy while higher myofibrillar proteins turn over. These changes are leading to the qualitative remodeling of muscle fibers. As a result of these changes, possible maximal muscle strength is increasing. Endurance exercise improves capillary blood supply, increases mitochondrial biogenesis and muscle oxidative capacity, and causes a faster turnover rate of sarcoplasmic proteins as well as qualitative remodeling of type I and IIA muscle fibers. The combination of resistance and endurance exercise may be the fastest way to prevent or decelerate muscle atrophy due to the anabolic and anticatabolic effects of exercise combined with an increase in oxidative capacity. The aim of the present short review is to assess the role of myofibrillar protein catabolism in the development of glucocorticoid-caused myopathy from aging and physical activity aspects.

Myopathies of endocrine disorders: A prospective clinical and biochemical study

Introduction:

Major categories of endocrine myopathy include those associated with: Adrenal dysfunction (as in Cushing's disease or steroid myopathy); thyroid dysfunction (as in myxedema coma or thyrotoxic myopathy); vitamin D deficiency; parathyroid dysfunction; and pituitary dysfunction. Steroid myopathy is the most common endocrine myopathy.

Objective:

To study the etiology, varied presentations, and outcome after therapy of patients with endocrine myopathies.

Materials and Methods:

Myopathy was evaluated by the standard clinical procedures: Detailed clinical history, manual muscle strength testing, and creatine phosphokinase (CPK). Endocrine disorders were diagnosed as per clinical features and biochemical parameters. The treatment was given to patients as per underlying endocrine disease. Myopathy was assessed before and after treatment.

Results:

Out of the 37 patients who were diagnosed with endocrine myopathies, thyroid dysfunction was the most common cause (17 cases), followed by vitamin D deficiency in nine, adrenal dysfunction in six, parathyroid dysfunction in three, and pituitary dysfunction in two. Some patients had atypical presentation (repeated falls in one, tongue fasciculations in one, neck weakness in five, one with ptosis and facial weakness, asymmetrical onset in one, and calf hypertrophy in one. The serum creatine kinase (CK) concentration did not correlate with muscle weakness. Following the treatment regimen which was specific for a given myopathy, 26 patients recovered fully.

Conclusion:

We found varied clinical presentations of endocrine myopathies. All the patients with neuromuscular complaints should be investigated for endocrine causes because significant number of them recovers fully with specific treatment.

Neurologic manifestations of inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are chronic, relapsing and remitting inflammatory conditions affecting the digestive system, comprising two main distinctive diseases, ulcerative colitis (UC) and Crohn's disease (CD). Besides the classic gastrointestinal manifestations, a variable number of IBD patients present with extraintestinal manifestations, including central and peripheral nervous system involvement. Peripheral neuropathy is one of the most common complications. An inflammatory myopathy has also been found. Cranial neuropathies include the Melkersson-Rosenthal syndrome, optic neuritis, and sensorineural hearing loss. Patients with IBD have a remarkable thromboembolic tendency and are at increased risk of both venous and arterial thrombotic complications. The prothrombotic state in IBD has multiple contributors. Ischemic stroke occurs through several mechanisms, including large artery disease, small vessel disease, paradoxical embolism, endocarditis, vasculitis, and associated with anti-TNF-α therapy. Thrombosis of the dural sinus and cerebral veins are at least as frequent as arterial stroke in IBD. Multiple sclerosis has been repeatedly associated with IBD. Up to 50% of IBD present asymptomatic white matter lesions. Other central nervous system complications include a slowly progressive myelopathy, epidural and subdural spinal empyema secondary to fistulous extension from the rectum, seizures, and encephalopathy.

Glucocorticoid-induced myopathy: Pathophysiology, diagnosis, and treatment

Glucocorticoid-induced myopathy is the most common type of drug-induced myopathy. Nearly 60% of patients with Cushing's syndrome have muscle weakness. Glucocorticoid-induced muscle atrophy affects mainly fast-twitch glycolytic muscle fibers (type IIb fibers). This brief review will discuss the pathophysiology behind glucocorticoid-induced myopathy, along with diagnostic features and treatment.

Corticosteroids in brain cancer patients: benefits and pitfalls

Glucocorticoids have been used for decades in the treatment of brain tumor patients and belong to the most powerful class of agents in reducing tumor-associated edema and minimizing side effects and the risk of encephalopathy in patients undergoing radiation therapy. Unfortunately, corticosteroids are associated with numerous and well-characterized adverse effects, constituting a major challenge in patients requiring long-term application of corticosteroids. Novel antiangiogenic agents, such as bevacizumab (Avastin®), which have been increasingly used in cancer patients, are associated with significant steroid-sparing effects, allowing neuro-oncologists to reduce the overall use of corticosteroids in patients with progressive malignant brain tumors. Recent experimental studies have revealed novel insights into the mechanisms and effects of corticosteroids in cancer patients, including modulation of tumor biology, angiogenesis and steroid-associated neurotoxicity. This article summarizes current concepts of using corticosteroids in brain cancer patients and highlights potential pitfalls in their effects on both tumor and neural progenitor cells.

Long-term observational study of sporadic inclusion body myositis

We describe a long-term observational study of a large cohort of patients with sporadic inclusion body myositis and propose a sporadic inclusion body myositis weakness composite index that is easy to perform during a clinic. Data collection from two groups of patients (Paris and Oxford) was completed either during a clinic visit (52%), or by extraction from previous medical records (48%). One hundred and thirty-six patients [57% males, 61 (interquartile range 55-69) years at onset] were included. At the last visit all patients had muscle weakness (proximal British Medical Research Council scale <3/5 in 48%, distal British Medical Research Council scale <3/5 in 40%, swallowing problems in 46%). During their follow-up, 75% of patients had significant walking difficulties and 37% used a wheelchair (after a median duration from onset of 14 years). The sporadic inclusion body myositis weakness composite index, which correlated with grip strength (correlation coefficient: 0.47; P < 0.001) and Rivermead Mobility Index (correlation coefficient: 0.85; P < 0.001), decreased significantly with disease duration (correlation coefficient: -0.47; P < 0.001). The risk of death was only influenced by older age at onset of first symptoms. Seventy-one (52%) patients received immunosuppressive treatments [prednisone in 91.5%, associated (in 64.8%) with other immunomodulatory drugs (intravenous immunoglobulins, methotrexate or azathioprine) for a median duration of 40.8 months]. At the last assessment, patients who had been treated were more severely affected on disability scales (Walton P = 0.007, Rivermead Mobility Index P = 0.004) and on the sporadic inclusion body myositis weakness composite index (P = 0.04). The first stage of disease progression towards handicap for walking was more rapid among patients receiving immunosuppressive treatments (hazard ratio = 2.0, P = 0.002). This study confirms that sporadic inclusion body myositis is slowly progressive but not lethal and that immunosuppressive treatments do not ameliorate its natural course, thus confirming findings from smaller studies. Furthermore, our findings suggest that immunosuppressant drug therapy could have modestly exacerbated progression of disability. The sporadic inclusion body myositis weakness composite index might be a valuable outcome measure for future clinical trials, but requires further assessment and validation.

Steroid myopathy: some unresolved issues

Steroid myopathy is a non-inflammatory toxic myopathy that occurs as side effect of exogenous and endogenous glucocorticoid excess. The purpose of this review is to examine issues that limit our understanding of this myopathy with respect to nosology, etiopathogenesis, conditioning factors, and muscle fiber selectivity. We suggest that if more data were available on these issues, the understanding of steroid myopathy would be enhanced substantially, thus allowing an early detection of its occurrence (before the appearance of clinical or laboratory signs) and a proper treatment of the patients.

Acute myopathy secondary to oral steroid therapy in a 49-year-old man: a case report

INTRODUCTION

Acute myopathy caused by oral corticosteroids is rare. We present a case of myopathy occurring after two doses of methylprednisolone. Typically, acute steroid myopathy occurs with therapy using intravenous corticosteroids at high doses. Acute myopathy developing very early in the course of treatment with oral corticosteroids has been reported only once in the literature. Corticosteroid therapy may be complicated by myopathy, usually chronic, after prolonged high-dose therapy. Acute myopathy caused by exogenous corticosteroids is rare, usually with intravenous corticosteroids at high doses.

CASE PRESENTATION

A 49-year-old Caucasian man developed acute myopathy after taking oral methylprednisolone for only two days, 24 mg on day 1 and 20 mg on day 2. He discontinued the medication because of new-onset myalgias and lethargy on day 3 and was seen in our clinic four days after beginning therapy. He completely recovered in four weeks by discontinuing the corticosteroids.

CONCLUSION

Among the many complications of corticosteroid therapy, acute myopathy is very rare. It requires prompt recognition and adjustment of therapy.

Corticosteroid effects on ventilator-induced diaphragm dysfunction in anesthetized rats depend on the dose administered

BACKGROUND

High dose of corticosteroids has been previously shown to protect against controlled mechanical ventilation (CMV)-induced diaphragmatic dysfunction while inhibiting calpain activation. Because literature suggests that the calpain inhibiting effect of corticosteroid depends on the dose administered, we determined whether lower doses of corticosteroids would also provide protection of the diaphragm during CMV. This may be important for patients undergoing mechanical ventilation and receiving corticosteroids.

METHODS

Rats were assigned to controls or to 24 hours of CMV while being treated at the start of mechanical ventilation with a single intramuscular administration of either saline, or 5 mg/kg (low MP) or 30 mg/kg (high MP) of methylprednisolone.

RESULTS

Diaphragmatic force was decreased after CMV and this was exacerbated in the low MP group while high MP rescued this diaphragmatic dysfunction. Atrophy was more severe in the low MP group than after CMV while no atrophy was observed in the high MP group. A significant and similar increase in calpain activity was observed in both the low MP and CMV groups whereas the high dose prevented calpain activation. Expression of calpastatin, the endogenous inhibitor of calpain, was decreased in the CMV and low MP groups but its level was preserved to controls in the high MP group. Caspase-3 activity increased in all CMV groups but to a lesser extent in the low and high MP groups. The 20S proteasome activity was increased in CMV only.

CONCLUSIONS

Administration of 30 mg/kg methylprednisolone during CMV protected against CMV-induced diaphragm dysfunction while 5 mg/kg was more deleterious. The protective effect is due mainly to an inhibition of the calpain system through preservation of calpastatin levels and to a lesser extent to a caspase-3 inhibition.

Evaluation and management of osteoporosis and fragility fractures in the elderly

Osteoporosis is characterized by low bone mass and microarchitectural deterioration that leads to increased bone fragility and fracture. The medical, psychosocial and economic burden that fragility fractures have on individuals and society is staggering. As the geriatric segment of the population continues to expand, so to will the magnitude of this epidemic. There are multiple mechanisms influencing bone quality and bone loss with age. Fragility fracture is a composite of multiple intrinsic and extrinsic factors related to the individual and their environment. Fall prevention remains the cornerstone of management in this problem. The FRAX® fracture risk assessment program, which estimates the 10-year probability of a major osteoporotic fracture, is an exciting new tool in assessing risk. Novel therapeutics, including zoledronic acid, strontium and teriparatide, are now available to complement proven osteoporosis treatments and more effectively decrease fracture risk in vulnerable individuals. Agents in Phase III trials, including denosumab and lasofoxifene, will probably increase the armamentarium of tools clinicians can use to combat the growing problem of osteoporosis and its complications.

[Laboratory abnormalities and autoantibodies]

Laboratory tests in inflammatory myopathies (IIM) are of great help in the diagnosis of these diseases. Two main groups can be defined, one of them quantifies the muscle enzymes that reflect muscle inflammation and the other one detects the presence of autoantibodies which reflect the autoimmune process in these diseases. The most important muscle enzyme is creatine kinase and other enzymes to take into consideration are aspartate and alanine aminotransferase, aldolase and lactic dehydrogenase. In the autoantibodies group, antinuclear antibodies are the most important, since they occur in approximately 50-80% of patients with IIM and help define the distinct disease sub-groups. They are divided into myositis specific antibodies (MSA) and myositis associated antibodies (MAA). The most important MSA are anti-Jo-1 antibody which occur in patients with Polymyositis and anti-Mi-2 antibody that occur in patients with Dermatomyositis.

Signs of critical illness polyneuropathy and myopathy can be seen early in the ICU course

BACKGROUND

Critical illness polyneuropathy and myopathy (CIPNM) is recognized as a common condition that develops in the intensive care unit (ICU). It may lead to a prolonged hospital stay with subsequent increased ICU and hospital costs. Knowledge of predisposing factors is insufficient and the temporal pattern of CIPNM has not been well described earlier. This study investigated patients with critical illness in need of prolonged mechanical ventilation, describing comprehensively the time course of changes in muscle and nerve neurophysiology, histology and mitochondrial oxidative function.

METHODS

Ten intensive care patients were investigated 4, 14 and 28 days after the start of mechanical ventilation. Laboratory tests, neurophysiological examination, muscle biopsies and clinical examinations were performed. Neurophysiological criteria for CIPNM were noted and measurements for mitochondrial content, mitochondrial respiratory enzymes and markers of oxidative stress were performed.

RESULTS

While all patients showed pathologic changes in neurophysiologic measurements, only patients with sepsis and steroid treatment (5/5) fulfilled the CIPNM criteria. The presence of CIPNM did not affect the outcome, and the temporal pattern of CIPNM was not uniform. All CIP changes occurred early in ICU care, while myopathy changes appeared somewhat later. Citrate synthase was decreased between days 4 and 14, and mitochondrial superoxide dismutase was increased.

CONCLUSION

With comprehensive examination over time, signs of CIPNM can be seen early in ICU course, and appear more likely to occur in patients with sepsis and corticosteroid treatment.

Lack of association between glucocorticoid use and presence of the metabolic syndrome in patients with rheumatoid arthritis: a cross-sectional study

Introduction

Rheumatoid arthritis (RA) associates with excessive cardiovascular morbidity and mortality, attributed to both traditional and novel cardiovascular risk factors. The metabolic syndrome, a cluster of classical cardiovascular risk factors, including hypertension, obesity, glucose intolerance, and dyslipidaemia, is highly prevalent in RA. Reports suggest that long-term glucocorticoid (GC) use may exacerbate individual cardiovascular risk factors, but there have been no studies in RA to assess whether it associates with the metabolic syndrome. We examined whether GC exposure associates with the presence of metabolic syndrome in patients with RA.

Methods

RA patients (n = 398) with detailed clinical and laboratory assessments were categorised into three groups according to GC exposure: no/limited (<3 months) exposure (NE), low-dose (<7.5 mg/day) long-term exposure (LE), and medium-dose (greater than or equal to 7.5 mg to 30 mg/day) long-term exposure (ME). The metabolic syndrome was defined using the National Cholesterol Education Programme III guidelines. The association of GC exposure with the metabolic syndrome was evaluated using binary logistic regression.

Results

The metabolic syndrome was present in 40.1% of this population and its prevalence did not differ significantly between the GC exposure groups (NE 37.9% versus LE 40.7% versus ME 50%, P = 0.241). Binary logistic regression did not demonstrate any increased odds for the metabolic syndrome when comparing ME with LE (odds ratio = 1.64, 95% confidence interval 0.92 to 2.92, P = 0.094) and remained non significant after adjusting for multiple potential confounders.

Conclusions

Long-term GC exposure does not appear to associate with a higher prevalence of the metabolic syndrome in patients with RA. The components of the metabolic syndrome may already be extensively modified by other processes in RA (including chronic inflammation and treatments other than GCs), leaving little scope for additive effects of GCs.

Atrophy of type II fibres in myasthenia gravis muscle in thymectomized patients: steroid-induced change with prognostic impact

Selective atrophy of type II muscle fibres has been long recognized as an enigmatic but consistent feature of myasthenia gravis (MG) muscle; however, the pathophysiology and the mechanism of that change have remained obscure. In the present study, the results of histomorphometric analysis performed on muscle biopsies from 207 thymectomized seropositive MG patients were correlated with clinical features of MG to demonstrate possible pathophysiological associations and potential prognostic impact. The atrophy of type II fibres was verified in 35 cases (16.9%), being more pronounced in fibres of IIB subtype. It was neither significantly associated with the duration and severity of MG nor with the age of the patients. On the other hand, we demonstrated that the atrophy associated with long-term treatment with corticosteroids, and correlated with increasing doses. Thus, we suppose that the atrophy of type II muscle fibres in seropositive MG is steroid induced rather than MG-associated event. Although the MG patients with atrophy of type II fibres did not differ from the remaining MG cases in terms of improvement in the disease during the follow-up period, our analysis provides clear evidence that they presented a significantly slower tendency to reach an asymptomatic state after thymectomy. Therefore, the steroid-induced atrophy of type II fibres in MG muscle might be considered to be an unfavourable prognostic factor.

Mechanisms of neurologic failure in critical illness

Critical illness frequently is associated with neurologic failure that may involve the central and peripheral nervous systems. Central nervous system failure is associated with a spectrum of neurobehavioral changes including delirium, coma, and long-term cognitive dysfunction. Peripheral neurologic failure, or critical illness neuromuscular abnormalities, is suggested by diffuse arreflexic weakness and protracted respiratory insufficiency, and may also persist long after the acute hospitalization. While the burden of neurological disease complicating critical illness is considerable, preventive or therapeutic options are limited. This article provides an overview of research evaluating the relationship between critical illness and neurologic function, with a special emphasis on underlying mechanisms.

Corticosteroid-induced adverse events in adults: frequency, screening and prevention

Corticosteroids represent the most important and frequently used class of anti-inflammatory drugs and are the reference therapy for numerous neoplastic, immunological and allergic diseases. However, their substantial efficacy is often counter-balanced by multiple adverse events. These corticosteroid-induced adverse events represent a broad clinical and biological spectrum from mild irritability to severe and life-threatening adrenal insufficiency or cardiovascular events. The purpose of this article is to provide an overview of the available data regarding the frequency, screening and prevention of the adverse events observed in adults during systemic corticosteroid therapy (topically administered corticosteroids are outside the remit of this review). These include clinical (i.e. adipose tissue redistribution, hypertension, cardiovascular risk, osteoporosis, myopathy, peptic ulcer, adrenal insufficiency, infections, mood disorders, ophthalmological disorders, skin disorders, menstrual disorders, aseptic necrosis, pancreatitis) and biological (i.e. electrolytes homeostasis, diabetogenesis, dyslipidaemia) events. Lastly, data about the prescription of corticosteroids during pregnancy are provided. This review underscores the absence of data on many of these adverse events (e.g. lipodystrophy, dyslipidaemia). Our intent is to present to practitioners data that can be used in a practical way to both screen and prevent most of the adverse events observed during systemic corticosteroid therapy.

Atorvastatin-induced early-onset rhabdomyolysis in a patient with nephrotic syndrome

PURPOSE

A case of early-onset rhabdomyolysis in a patient treated with atorvastatin is described.

SUMMARY

A 17-year-old Indian boy weighing 55 kg was admitted to the hospital after complaining of facial puffiness and pedal edema for four days. His medical history revealed a diagnosis of nephrotic syndrome when he was 2 years old. He had six relapses, the last of which occurred 10 years ago. He was not taking any medications on admission and had not for the past 9 years. His vital signs were normal on admission (day 1), but anasarca was noticed during general examination. Cardiovascular, respiratory, and abdominal examinations were normal. Relapse of nephrotic syndrome was considered, and his 24-hour urine protein value confirmed the diagnosis. Further laboratory tests revealed that the patient had high total and low-density-lipoprotein cholesterol values (597 and 465 mg/dL, respectively), and atorvastatin 10 mg p.o. once daily was initiated on day 2. Prednisolone 60 mg p.o. once daily was initiated on day 3. On day 6, the patient complained of pain in both thighs and had difficulty walking. His creatine kinase (CK) concentration was then measured and found to be elevated (11,821 IU/L). Prednisolone and atorvastatin were then stopped, as statin-induced myopathy was suspected. The patient received i.v. hydration and sodium bicarbonate, and he began to show improvement by day 9. Follow-up three weeks later revealed a normal CK level and no myopathy-related complaints.

CONCLUSION

Early-onset rhabdomyolysis was reported in a patient with nephrotic syndrome who was treated with atorvastatin. Concomitant use of prednisolone and the patient's underlying renal impairment may have predisposed the patient to this adverse reaction.

Creatine supplementation attenuates corticosteroid-induced muscle wasting and impairment of exercise performance in rats

The objective of the present study was to investigate whether creatine (Cr) could attenuate the deleterious effects of high doses of dexamethasone (Dexa) on body mass, exercise performance, and respiratory variables of rodents. Forty-four Wistar rats performed incremental maximal exercise tests. They were then assigned to four groups: G1: subcutaneous (SC) and intraperitoneal (IP) saline; G2: SC saline and IP Cr (250 mg·kg−1·day−1); G3: SC Dexa (7.5 mg·kg−1·day−1) and IP saline; G4: SC Dexa and IP Cr. New exercise tests and analysis of the respiratory pattern under resting conditions and after stimulation with doxapram (2 mg/kg IP) were performed after 18 days. Post- minus pretreatment differences were compared between groups. G3 and G4 showed a significant impairment in body mass gain compared with G1 and G2 ( P < 0.05) (G1: 65.3 ± 26.1, G2: 93.1 ± 27.4, G3: −18.4 ± 20.1, G4: 9.8 ± 23.1 kg × 10−3). Similar results were observed for maximal oxygen consumption (G1: 9.5 ± 8.5, G2: 25.8 ± 14.5, G3: −25.5 ± 6.0, G4: −4.8 ± 9.5 ml·kg−1·min−1) and test duration (G1: 43.0 ± 45.0, G2: 72.0 ± 59.5, G3: −165.0 ± 60.6, G4: −48.0 ± 48.5 s). Simultaneous use of Cr significantly attenuated the Dexa-induced impairment of the last two variables. Cr attenuated Dexa-induced gastrocnemius and diaphragm muscle weight losses and the atrophy of gastrocnemius type IIb fibers. Cr supplementation had only small effects on Dexa-induced respiratory changes. These results suggest that Cr may play a role in the prophylaxis or treatment of steroid-induced myopathy.

Evidence-based guidelines for the prevention and treatment of glucocorticoid-induced osteoporosis: a consensus document of the Belgian Bone Club

Glucocorticoids (GCs) are frequently prescribed for various inflammatory and/or life-threatening conditions concerning many systems in the body. However, they can provoke many aftereffects, of which osteoporosis (OP) is one of the most crippling complications, with its host of fractures. The dramatic increase in bone fragility is mainly attributable to the GC-induced rapid bone loss in all skeletal compartments. We have reviewed the meta-analyses and randomized controlled studies reporting medical therapeutic interventions currently registered in Belgium for the management of GC-OP comparatively with a placebo. Based on this research, an expert meeting developed a consensus on the prevention and therapy of GC-OP. The pathophysiology of GC-OP is complex. Several factors, acting separately or synergistically, have been described. Their great number could help to understand the rapidity of bone loss and of bone fragility occurrence, indicating that a rapid therapeutic intervention should be implemented to avoid complications. All patients on GCs are threatened with OP, so the prevention and/or therapy of GC-OP should be considered not only for postmenopausal females, but also for osteopenic premenopausal females and for males put on a daily dose of at least 7.5 mg equivalent prednisolone that is expected to last at least 3 months. Non-pharmacological interventions, such as exercise and avoidance of tobacco and alcohol, should be recommended, even if their role is not definitely settled in GC-OP prevention. Supplemental calcium and vitamin D should be considered as the first-line therapy because of the decrease in intestinal calcium absorption provoked by GCs. They also could be considered either as isolated therapy in patients taking less than 7.5 mg prednisolone daily and/or for a predicted period shorter than 3 months or as adjuvant therapy to other more potent drugs. Hormone replacement therapy could be considered in young postmenopausal females on GC, such as in postmenopausal OP, or in men with low androgen levels. Calcitonin appears to have a protective effect on trabecular bone in GC-OP, just as in postmenopausal OP. There is an increasing body of evidence supporting the antifracture efficacy of bisphosphonates, notably alendronate and risedronate. Preventative and curative therapy of GC-OP should be maintained as long as the patient is on GC treatment and could be stopped after weaning from GC, because there is more than circumstantial evidence of some recovery of BMD when GCs are stopped. There is no indication in GC-OP for any combination of two antiresorptive agents (except for calcium and vitamin D) or for an antiresorptive and an anabolic agent. There is indeed no proof that the increased costs of combined treatments will translate into increased therapeutic efficacy.

Osteoporosis due to Glucocorticoid Use in Children with Chronic Illness

Osteoporosis is increasingly recognized as a complication of chronic childhood illnesses, particularly when glucocorticoids (GCs) are necessary for treatment. Elucidation of the mechanisms leading to bone fragility in these settings requires disentanglement of the relative contributions of myriad risk factors, including disease activity, muscle weakness, immobilization, delayed growth and puberty, compromised nutrition, and osteotoxic medications. Over the years, bone mass and density evaluations by dual energy X-ray absorptiometry (DXA) have become popular for assessing bone health in children; however, such measurements are difficult to interpret because of the confounding effect of bone size and the lack of DXA-based densitometric criteria for defining osteoporosis in childhood. Recently, a new diagnostic approach for evaluation of densitometric data in children has been suggested, driven by Frost's mechanostat theory. A diagnostic algorithm based on the mechanostat theory of bone-muscle development is proposed for the characterization of bone disease in children with chronic illness. In addition to DXA-based assessments, techniques such as peripheral quantitative computerized tomography and ilial histomorphometry, for which there are pediatric reference data, are gaining ground in the characterization of skeletal changes due to chronic illness. Although these diagnostic techniques expand our understanding of osteoporosis in children, they do not replace clinical assessment. Concrete clinical evidence for GC-induced bone fragility can be seen in spinal changes due to vertebral compression, with spinal morphometry emerging as an essential, but frequently overlooked, tool in the evaluation of children's bone health. Presently, osteoporosis treatment in the chronic illness setting remains experimental and should be restricted to clinical studies. Following an understanding of the natural history of GC-induced osteoporosis in children, randomized, placebo-controlled prevention and intervention trials will be the next step toward the development of clinical practice guidelines.

Neuromuscular rehabilitation and electrodiagnosis. 3. Diseases of muscles and neuromuscular junction

This self-directed learning module highlights formation of a differential diagnosis as well as electrodiagnostic evaluation for those patients who present with the common complaint of weakness. It is part of the chapter on neuromuscular rehabilitation and electrodiagnosis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on the common symptoms and typical clinical findings that allow the clinician to narrow the differential diagnosis. This is followed by the diagnostic evaluation, with emphasis on the technical aspects and interpretation of electrodiagnostic studies.

OVERALL ARTICLE OBJECTIVE

To summarize the clinical presentation and electrodiagnostic findings in persons with disorders of muscle or disorders of the neuromuscular junction.

Glucocorticoid-induced osteoporosis: from basic mechanisms to clinical aspects

Glucocorticoid (GC)-induced osteoporosis (GCOP) is the most common cause of osteoporosis in adults aged 20-45 years as well as the most common cause of iatrogenic osteoporosis. GC excess, either endogenous or exogenous, induces bone loss in 30-50% of cases. Indeed, bone loss leading to fractures is perhaps the most incapacitating, sometimes partially irreversible, complication of GC therapy. Nevertheless, GCOP is often underdiagnosed and left untreated. The following article provides an update on the cellular and molecular mechanisms implicated in the pathophysiology of GC-induced bone loss, as well as some guidelines on diagnostic, preventive and therapeutic strategies for this medical condition, in an effort to promote a better knowledge and greater awareness of GCOP by both the patient and the physician.

Muscle metabolites, detected in urine by proton spectroscopy, correlate with disease damage in juvenile idiopathic inflammatory myopathies

OBJECTIVE

To assess for novel markers of muscle damage using urinary muscle metabolites by 1H magnetic resonance spectroscopy in patients with juvenile idiopathic inflammatory myopathy (IIM).

METHODS

Creatine (Cr), choline (Cho), betaine (Bet), glycine (Gly), trimethylamine oxide (TMAO), and several other metabolites were measured in first morning void urine samples from 45 patients with juvenile IIM and from 35 healthy age-matched controls, and correlated with measures of myositis disease activity and damage. Urinary metabolite to age-adjusted creatinine (Cn) ratios were examined.

RESULTS

Age-adjusted initial Cr:Cn, Cho:Cn, Bet:Cn, Gly:Cn, and TMAO:Cn ratios were higher in patients with juvenile IIM than controls (P < 0.01). Cr:Cn ratios showed significant correlations with physician-assessed global disease damage (Spearman rs = 0.37; P = 0.01), Steinbrocker functional class (rs = 0.35; P = 0.02), serum Cr (rs = 0.72; P = 0.001), and lactate dehydrogenase (rs = 0.34; P = 0.03) levels. Cho:Cn (rs = 0.3; P = 0.05), Gly:Cn (rs = 0.33; P = 0.03), and TMAO:Cn (rs = 0.36; P = 0.02) ratios showed a significant correlation with serum aldolase levels. Cho:Cn ratios also showed a significant correlation with aspartate aminotransferase levels (rs = 0.35; P = 0.02). A linear regression model was used to evaluate the factors influencing urinary Cr:Cn ratios in the 43 patients with data sets available at the initial visit. The regression model explained 73% of the variation in Cr:Cn ratios. The most significant factor was the physician-assessed global disease damage (R2 = 0.50, P = 0.015).

CONCLUSION

Urinary Cr:Cn, Cho:Cn, Bet:Cn, Gly:Cn, and TMAO:Cn ratios are elevated in juvenile IIM and Cr:Cn correlates strongly with global disease damage. The Cr:Cn ratio may have potential utility as a marker of myositis disease damage.

Corticosteroid use in the treatment of neuromuscular disorders: empirical and evidence-based data

Corticosteroids have been used to treat neuromuscular disorders for many years. With few randomized, controlled trials, efficacy has been established primarily from empirical data. This has led to a range of treatment regimens varying in terms of initial dosing, dosing schedules, and taper rates. The goals of this review were to examine the literature for data concerning corticosteroid pharmacokinetics and for evidence-based treatment regimens in several prototypic neuromuscular disorders. The results provide a number of sound principles for corticosteroid use, but also indicate that corticosteroid regimens and patient management are largely based on empirical clinical experiences.