Drug-related myopathies of which the clinician should be aware

Asymptomatic COVID-19 Infection-Induced Rhabdomyolysis in the Backdrop of Statin-Cyclosporine Drug Interaction

Rhabdomyolysis involves skeletal muscle breakdown leading to high serum creatine kinase (CK) levels and myoglobinuria. Here, we report the case of a middle-aged man who developed rhabdomyolysis, resulting in acute kidney injury (AKI) over pre-existing chronic kidney disease (stage 3a) secondary to focal segmental glomerulosclerosis (primary FSGS), during an asymptomatic COVID-19 infection. The patient had been on treatment with cyclosporine and statin, among other drugs, for his comorbidities. He had initially presented to the hospital after a fall due to difficulty walking in the setting of increasing edema. Lab workup revealed elevated CK and AKI. Urinalysis showed "large" blood on a dipstick with only two RBCs per high-power field on microscopy, suggesting myoglobinuria. A standard respiratory pathogen polymerase chain reaction panel revealed positive SARS-CoV-2. The chest X-ray and oxygenation were normal, and he had no respiratory symptoms. He was treated with intravenous fluids and albumin, with a steady improvement in renal function. Our case underlines that rhabdomyolysis can occur in asymptomatic COVID-19 infection. Therefore, it may be worth monitoring CK levels in COVID-19-positive patients with risk factors for rhabdomyolysis, such as the concurrent usage of statins and cyclosporine, even if they are otherwise asymptomatic.

Practical Management of the JAK1 Inhibitor Abrocitinib for Atopic Dermatitis in Clinical Practice: Special Safety Considerations

Abrocitinib, an oral, once-daily, Janus kinase (JAK) 1-selective inhibitor, is approved for the treatment of adults and adolescents with moderate-to-severe atopic dermatitis (AD). Abrocitinib has shown rapid and sustained efficacy in phase 3 trials and a consistent, manageable safety profile in long-term studies. Rapid itch relief and skin clearance are more likely to be achieved with a 200-mg daily dose of abrocitinib than with dupilumab. All oral JAK inhibitors are associated with adverse events of special interest and laboratory changes, and initial risk assessment and follow-up monitoring are important. Appropriate selection of patients and adequate monitoring are key for the safe use of JAK inhibitors. Here, we review the practical use of abrocitinib and discuss characteristics of patients who are candidates for abrocitinib therapy. In general, abrocitinib may be used in all appropriate patients with moderate-to-severe AD in need of systemic therapy, provided there are no contraindications, e.g., in patients with active serious systemic infections and those with severe hepatic impairment, as well as pregnant or breastfeeding women. For patients aged ≥ 65 years, current long-time or past long-time smokers, and those with risk factors for venous thromboembolism, major adverse cardiovascular events, or malignancies, a meticulous benefit-risk assessment is recommended, and it is advised to start with the 100-mg dose, when abrocitinib is the selected treatment option.

Rhabdomyolysis Suspected to be Caused by Eravacycline Therapy: A Case Report

Eravacycline is approved by the U.S. Food and Drug Administration (FDA) for the treatment of complicated intra-abdominal infections. It is a novel, fully synthetic fluorocycline antibiotic belonging to the tetracycline class with a broad-spectrum of activity and an appealing side effect profile. This report describes a 74-year-old female who presented to the hospital with non-ST-elevation myocardial infarction (NSTEMI) requiring coronary artery bypass graft surgery. After surgery, she developed a sternal wound infection that grew multidrug resistant organisms, leading to a much longer than anticipated hospital stay. Eravacycline was eventually added to the antimicrobial regimen for the persistent infection. Shortly after therapy with eravacycline began, the patient started experiencing muscle pain and the creatine phosphokinase (CPK) level was noted to be elevated. Other causes, such as concomitant administration of an HMG-CoA reductase inhibitor, were explored in this case but not thought to be the cause of rhabdomyolysis. The patient's CPK dropped considerably upon discontinuation of the novel antibiotic, and symptoms resolved. The adverse drug event was reported to the drug manufacturer; however, there are no reports up until this time that address a possible relationship between eravacycline administration and the development of rhabdomyolysis.

A 25-Year-Old Military Recruit with Isolated Myositis Following Routine Chemoprophylaxis with Intramuscular Benzathine Penicillin G

BACKGROUND Myositis is an inflammatory myopathy that can be caused by a variety of drugs, diseases, and toxins. The U.S. military uses chemoprophylaxis with intramuscular penicillin G to prevent group A streptococcal infection. We present a case of penicillin G-induced myositis, a rare cause of drug-induced myositis with limited discussion in the medical literature. CASE REPORT A 25-year-old man with no pertinent medical history presented to the Emergency Department with right hip and leg pain after receiving a single dose of intramuscular penicillin G as part of standard prophylaxis for group A streptococcal infection during basic military training. He reported pain and leg weakness that was exacerbated by physical exertion and weight bearing but had no systemic symptoms, such as fevers or chills. Initial radiographs of the hip were normal; however, subsequent magnetic resonance imaging of the hip revealed intramuscular edema and features consistent with myositis of the right proximal thigh and hip musculature. He was admitted for isolated right gluteal myositis, attributed to his preceding local penicillin injection. He recovered with symptomatic care over the following 2 weeks, with return to baseline function. CONCLUSIONS This case highlights a rare complication of intramuscular penicillin G as a cause of acute isolated myositis. It serves to inform physicians of this rare complication and to recommend the consideration of intramuscular penicillin G as a causative etiology in individuals presenting with myositis and recent penicillin G exposure.

Advances in research on cell models for skeletal muscle atrophy

Skeletal muscle, the largest organ in the human body, plays a crucial role in supporting and defending the body and is essential for movement. It also participates in regulating the processes of protein synthesis and degradation. Inhibition of protein synthesis and activation of degradation metabolism can both lead to the development of skeletal muscle atrophy, a pathological condition characterized by a decrease in muscle mass and fiber size. Many physiological and pathological conditions can cause a decline in muscle mass, but the underlying mechanisms of its pathogenesis remain incompletely understood, and the selection of treatment strategies and efficacy evaluations vary. Moreover, the early symptoms of this condition are often not apparent, making it easily overlooked in clinical practice. Therefore, it is necessary to develop and use cell models to understand the etiology and influencing factors of skeletal muscle atrophy. In this review, we summarize the methods used to construct skeletal muscle cell models, including hormone, inflammation, cachexia, genetic engineering, drug, and physicochemical models. We also analyze, compare, and evaluate the various construction and assessment methods.

Intravesical bacillus Calmette-Guérin-induced myopathy presenting as rhabdomyolysis: a case report

Intravesical bacillus Calmette-Guérin (BCG) instillation is an adjuvant treatment for non-muscle-invasive urinary bladder cancer. Although most complications associated with BCG immunotherapy are mild and self-limiting, rare albeit serious complications have been reported. Only a few cases of BCG-related rhabdomyolysis have been reported. In this study, we present the case of a 72-year-old woman who developed severe weakness and hyperCKemia following intravesical BCG instillation. A muscle biopsy was performed, and a diagnosis of drug-induced myopathy was made.

Is It Polymyositis?

How to cite this article: Bansal T. Is It Polymyositis? Indian J Crit Care Med 2023;27(9):690-691.

Standards of care for CFTR variant-specific therapy (including modulators) for people with cystic fibrosis

Cystic fibrosis (CF) has entered the era of variant-specific therapy, tailored to the genetic variants in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. CFTR modulators, the first variant-specific therapy available, have transformed the management of CF. The latest standards of care from the European CF Society (2018) did not include guidance on variant-specific therapy, as CFTR modulators were becoming established as a novel therapy. We have produced interim standards to guide healthcare professionals in the provision of variant-specific therapy for people with CF. Here we provide evidence-based guidance covering the spectrum of care, established using evidence from systematic reviews and expert opinion. Statements were reviewed by key stakeholders using Delphi methodology, with agreement (≥80%) achieved for all statements after one round of consultation. Issues around accessibility are discussed and there is clear consensus that all eligible people with CF should have access to variant-specific therapy.

Identification of Agents That Ameliorate Hyperphosphatemia-Suppressed Myogenin Expression Involved in the Nrf2/p62 Pathway in C2C12 Skeletal Muscle Cells

Hyperphosphatemia can occur as a result of reduced phosphate (P_i) excretion in cases of kidney dysfunction, which can induce muscle wasting and suppress myogenic differentiation. Higher P_i suppresses myogenic differentiation and promotes muscle atrophy through canonical (oxidative stress-mediated) and noncanonical (p62-mediated) activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. However, the crosstalk between myogenin and Nrf2/p62 and potential drug(s) for the regulation of myogenin expression needed to be addressed. In this study, we further identified that myogenin may negatively regulate Nrf2 and p62 protein levels in the mouse C2C12 muscle cell line. In the drug screening analysis, we identified N-acetylcysteine, metformin, phenformin, berberine, 4-chloro-3-ethylphenol, cilostazol, and cilomilast as ameliorating the induction of Nrf2 and p62 expression and reduction in myogenin expression that occur due to high P_i. We further elucidated that doxorubicin and hydrogen peroxide reduced the amount of myogenin protein mediated through the Kelch-like ECH-associated protein 1/Nrf2 pathway, differently from the mechanism of high Pi. The dual functional roles of L-ascorbic acid (L-AA) were found to be dependent on the working concentration, where concentrations below 1 mM L-AA reversed the effect of high P_i on myogenin and those above 1 mM L-AA had a similar effect of high P_i on myogenin when used alone. L-AA exacerbated the effect of hydrogen peroxide on myogenin protein and had no further effect of doxorubicin on myogenin protein. In summary, our results further our understanding of the crosstalk between myogenin and Nrf2, with the identification and verification of several potential drugs that can be applied in rescuing the decline of myogenin due to high P_i in muscle cells.

Bilateral upper extremity myositis after COVID-19 vaccination

Vaccination adverse reactions are common and usually are represented by transitory pain and edema. We present a case of bilateral muscle edema involving shoulders and arms due to myositis following COVID-19 vaccination, and focus on the imaging findings to differentiate with other diagnosis such as infection and tumors.

Ascorbic Acid Significantly Decreases Creatine Kinase Plasma Levels in an Animal Model of Statin/Fibrate-Induced Myopathy

Background

Myopathy is one of the side effects of lipid-lowering drugs, especially statins and particularly when combined with a fibrate. To diagnose myopathy and determine its severity, the plasma levels of three enzymes, creatine kinase (CK), aldolase, and lactate dehydrogenase (LDH), are routinely measured. Physical exercise can aggravate the statin-associated muscular disease. The question is whether antioxidants like ascorbic acid (Vit. C) can prevent such myopathy.

Methods

In this experiment, a combination of atorvastatin (ATV, 80 mg/kg/day) and gemfibrozil (GMF, 1000 mg/kg/day) orally for 10 days as well as exercise as forced swimming on days 8, 9, and 10 were used to induce myopathy. Ascorbic acid (50 mg/kg/day, orally) was added to ATV/GMF plus exercise regimen throughout the 10 days in the treatment group. Mean blood levels of CK, aldolase, and LDH were measured in addition to swimming tolerance times.

Results

There was a significantly higher swimming tolerance time (P < 0.05) and lower CK levels (P < 0.01) in rats receiving ATV/GMF/Vit. C plus exercise compared with rats not taking Vit. C. LDH and aldolase did not decrease significantly.

Conclusion

The results of this study showed that Vit. C can be effective in preventing myopathy caused by fat-lowering drugs.

Azole-Induced Myositis after Combined Lung-Liver Transplantation

Lung transplant recipients experience a high rate of invasive pulmonary aspergillosis infections, for which voriconazole is the treatment of choice. We report a patient who developed voriconazole-induced myositis that relapsed after one dose of isavuconazole. Our patient was a 38-year-old man who received a single sequential lung transplantation and liver transplantation because of end-stage cystic fibrosis. He presented to our emergency room with acute pain in both forearms at 3 weeks after voriconazole was initiated for invasive pulmonary aspergillosis infection. Levels of voriconazole were normal during the course of therapy. After stopping voriconazole, the symptoms decreased but relapsed after one dose of isavuconazole. Other causes of muscle pain and inflammation were excluded. Magnetic resonance imaging of both arms showed muscle edema in both arms, including involvement of the fascia, consistent with myositis. There were no signs of necrosis. Isavuconazole was discontinued, and the corticosteroid dose was temporarily increased, with rapid resolution of all complaints. Our patient is the fourth reported case of voriconazole-induced myositis, and the first whose symptoms relapsed after initiating isavuconazole.

Successful treatment of tuberculosis combined with drug-induced myopathy using corticosteroid therapy: a case report

A 39-year-old woman was admitted to our hospital on 19 January 2019 because of a 10-day history of intolerance to oils in her food, fatigue, and yellowing of the skin and sclera. In December 2018, the patient had been diagnosed with tuberculous pleurisy at a local hospital and received quadruple anti-tuberculosis treatment. Ten days before presentation to our hospital, she had developed anorexia, fatigue, nausea, loss of appetite, cough, and shortness of breath. She visited a local hospital, where she was considered to have drug-induced hepatitis. She discontinued the anti-tuberculosis drugs and liver protection treatment. After 3 days, her symptoms had not substantially improved. She visited the infection department of our hospital for further diagnosis and treatment. After 6 days of treatment, the patient's symptoms were not significantly improved, her liver and muscle enzyme concentrations were further increased, and her limbs had become weaker and more difficult to move. We considered diagnoses of drug-induced hepatitis and drug-induced myopathy. The patient was treated with intravenous methylprednisolone at 40 mg once a day for 16 days and other symptomatic treatments. Her symptoms significantly improved and she was discharged.

A case of trastuzumab-induced dermatomyositis

Human epidermal growth factor receptor 2 (HER-2) is a checkpoint, controlling cell proliferation and differentiation. Trastuzumab, a humanized monoclonal antibody directed against HER-2, is nowadays standard treatment for breast cancer patients whose tumors express HER-2. It is generally well tolerated, with a small number of patients developing mild adverse reactions. Dermatomyositis is a rare adverse event of trastuzumab therapy not well described in the literature. We herein present a case of a patient treated for hormone-sensitive invasive ductal carcinoma, who presented with symptoms of proximal muscle weakness, arthralgias, skin rash, and generalized fatigue. The symptoms started after the sixth cycle of trastuzumab and progressively deteriorated. The patient's medical and family history was unremarkable. Disease progression as a possible cause of dermatomyositis had been ruled out, and laboratory evaluation revealed moderate elevation of serum muscle proteins and acute-phase reactants. Trastuzumab treatment was discontinued, and 3 months later, the patient was free of symptoms without any further intervention.

The toxic effects of chloroquine and hydroxychloroquine on skeletal muscle: a systematic review and meta-analysis

The aim of this systematic review was to perform qualitative and quantitative analysis on the toxic effects of chloroquine (CQ) and hydroxychloroquine (HCQ) on skeletal muscles. We designed the study according to PRISMA guidelines. Studies for qualitative and quantitative analyses were selected according to the following inclusion criteria: English language; size of sample (> 5 patients), adult (> age of 18) patients, treated with CQ/HCQ for inflammatory diseases, and presenting and not presenting with toxic effects on skeletal muscles. We collected data published from 1990 to April 2020 using PubMed, Cochrane Library, EMBASE, and SciELO. Risk of bias for observational studies was assessed regarding the ROBIN-I scale. Studies with less than five patients (case reports) were selected for an additional qualitative analysis. We used the software Comprehensive Meta-Analysis at the confidence level of 0.05. We identified 23 studies for qualitative analysis (17 case-reports), and five studies were eligible for quantitative analysis. From case reports, 21 patients presented muscle weakness and confirmatory biopsy for CQ/HCQ induced myopathy. From observational studies, 37 patients out of 1,367 patients from five studies presented muscle weakness related to the use of CQ/HCQ, and 252 patients presented elevated levels of muscle enzymes (aldolase, creatine phosphokinase, and lactate dehydrogenase). Four studies presented data on 34 patients with confirmatory biopsy for drug-induced myopathy. No study presented randomized samples. The chronic use of CQ/HCQ may be a risk for drug-induced myopathy. There is substantiated need for proper randomized trials and controlled prospective studies needed to assess the clinical and subclinical stages of CQ/HCQ -induced muscle myopathy.

Acute idiopathic thenar and hypothenar compartment syndrome

Compartment syndrome (CS) is a condition associated with intra-compartment pressures exceeding the perfusion pressure of the tissue. This condition can occur in any body compartment surrounded by fascia, however CS of some regions like the thenar and hypothenar is extremely rare. Acute CS is often caused by major trauma and idiopathic acute CS is sparsely reported in literature. We present a case report of a 39-year-old male, with a medical history of rheumatoid arthritis (RA) for which he uses adalimumab and low-dose prednisone, with idiopathic acute CS of thenar and hypothenar compartments. Unexplained tremendous pain, paresthesia and swelling of his hand were the only symptoms observed. Due to direct recognition of the condition there was no delay in time to treatment. Treatment involved a fasciotomy of the thenar and hypothenar compartments as well as a release of the carpal tunnel. This direct surgical approach resulted in retaining excellent function and appearance of the hand. We hypothesized several causes for the etiology of the condition (e.g. rhabdomyolysis, rheumatologic disease-related condition, other systemic diseases, trauma, infection), but all could be rejected based on laboratory or clinical findings. Remarkable is that the patient experienced a comparable episode in his other hand two years earlier. Although the acute CS is of unknown origin in the presented case, the development of acute CS in both hands over time suggests a predisposing factor in idiopathic acute CS that is far from being elucidated.

Myopathy Associated With Statins and SGLT2 - A Review of Literature

Drug-induced myopathy is a well-described clinical entity characterized by muscle damage leading to symptoms ranging from myalgias to rhabdomyolysis and acute kidney injury. Many pharmacotherapies are known to precipitate myopathic symptoms. Recent case reports suggest a potential relationship between the use of sodium/glucose cotransport 2 (SGLT2) inhibitors and onset of myopathy. The pathogenesis of this has yet to be elucidated. The relevance of this association is augmented by the recent popularity of SGLT2 inhibitors as well as the tendency for them to be prescribed alongside statins. This study reviewed the literature on the incidence and mechanism of drug-induced myopathy in patients with type 2 diabetes mellitus who are taking SGLT2 inhibitors with and without the use of statins.

Stem Cell-Derived Exosomes Ameliorate Doxorubicin-Induced Muscle Toxicity through Counteracting Pyroptosis

Doxorubicin (Dox)-induced muscle toxicity (DIMT) is a common occurrence in cancer patients; however, the cause of its development and progression is not established. We tested whether inflammation-triggered cell death, “pyroptosis” plays a role in DIMT. We also examined the potential role of exosomes derived from embryonic stem cells (ES-Exos) in attenuating DIMT. C57BL/6J mice (10 ± 2 wks age) underwent the following treatments: Control (saline), Dox, Dox+ES-Exos, and Dox+MEF-Exos (mouse-embryonic fibroblast-derived exosomes, negative control). Our results demonstrated that Dox significantly reduced muscle function in mice, which was associated with a significant increase in NLRP3 inflammasome and initiation marker TLR4 as compared with controls. Pyroptosis activator, ASC, was significantly increased compared to controls with an upregulation of specific markers (caspase-1, IL-1β, and IL-18). Treatment with ES-Exos but not MEF-Exos showed a significant reduction in inflammasome and pyroptosis along with improved muscle function. Additionally, we detected a significant increase in pro-inflammatory cytokines (TNF-α and IL-6) and inflammatory M1 macrophages in Dox-treated animals. Treatment with ES-Exos decreased M1 macrophages and upregulated anti-inflammatory M2 macrophages. Furthermore, ES-Exos showed a significant reduction in muscular atrophy and fibrosis. In conclusion, these results suggest that DIMT is mediated through inflammation and pyroptosis, which is attenuated following treatment with ES-Exos.

Pregabalin-Induced Myopathy in a Double Lung Transplant Recipient

Pregabalin is a gamma-aminobutyric acid (GABA) derivative that was commercially approved by the Food and Drug Administration (FDA) in 2004. It is commonly used in the treatment of diabetic neuropathy, peripheral neuropathy, and spinal cord injury. We present the case of a 36-year-old Caucasian male double lung transplant recipient who presented with an 18-month history of fatigue and muscle weakness. He had elevated creatinine kinase level and his muscle biopsy showed evidence of drug-induced myopathy that improved after the cessation of pregabalin. We present a case of drug-induced myopathy as a rare complication of pregabalin therapy in a double lung transplant recipient.

The impact of SARS-CoV-2 on skeletal muscles

In 2019-2020, the SARS-CoV-2 pandemic has shocked the world and most health care systems, and a “second wave” of the viral spread is ongoing in Europe and in Italy too. While, at the initial outbreak, the treatment of patients had focused on the respiratory symptoms, many diverse clinical manifestations of the disease have to date been reported. However, the complete course of the disease has not yet been fully clarified. In particular, several reports from the real-world clinical practice have highlighted the noxious effects of SARS-CoV-2 on skeletal muscles. In this brief review, we summarized the main current findings about muscular and neuromuscular damages that may be triggered by the virus or by the drugs used to treat COVID-19. Moreover, we underlined the need of attentive care and vigilance for patients with neuro-muscular disorders, who may be particularly susceptible to infection and at increased risk for severe COVID-19.

Safety outcomes with high-dose daptomycin in patients with acute kidney injury and/or end-stage renal disease

WHAT IS KNOWN

Daptomycin is associated with a number of adverse effects including eosinophilic pneumonia, hypersensitivity reaction, myopathy, rhabdomyolysis, headache and transaminitis. The adverse effects of high-dose daptomycin have not been fully evaluated in patients with end-stage renal disease (ESRD).

OBJECTIVE

To determine the incidence and characteristics of significant adverse effects in patients receiving high-dose daptomycin with severe renal dysfunction.

METHODS

A single-centre, retrospective study was conducted to assess safety outcomes of high-dose daptomycin in patients with an estimated creatinine clearance less than 30 mL/min. Adult patients aged 18 to 89 years admitted between 1 July 2015 and 1 July 2019 were eligible for inclusion. Patients must have received definitive daptomycin therapy with doses greater than or equal to 7.5 mg/kg based on actual body weight. The primary outcome was overall incidence of creatine phosphokinase (CK) elevation, myopathy and rhabdomyolysis.

RESULTS AND DISCUSSION

A total of 74 patients who received daptomycin therapy were screened with 50 included in the study. The population was well distributed in terms of gender (48% male, n = 24) with a median age of 61 (IQR, 48-67) years. The primary indication for daptomycin use was Gram-positive bacteremia. The median daptomycin dose was 750 (IQR, 600-875) mg, or 8.46 (IQR, 7.92-9.96) mg/kg based on actual body weight, with a median patient weight of 81 (IQR, 65-113) kg. The median duration of therapy was 27 (IQR, 14-42) days. One patient experienced significant CK elevation while on daptomycin therapy with rhabdomyolysis; however, daptomycin was continued as there was an alternative explanation for an elevated CK. One patient experienced daptomycin discontinuation due to CK elevation without meeting the definition for significant CK elevation.

WHAT IS NEW AND CONCLUSION

In a cohort of patients with severe renal dysfunction treated with daptomycin 7.5 mg/kg or greater, significant CK elevation on daptomycin therapy was infrequently observed. Future research should confirm these findings, with special consideration for higher mg/kg dosages and/or obese populations.

Myopathy secondary to empagliflozin therapy in type 2 diabetes

SUMMARY

Sodium/glucose co-transporter 2 (SGLT2) inhibitors are novel oral hypoglycaemic agents that are increasingly used in the management of type 2 diabetes mellitus (T2DM). They are now recommended as second-line pharmacotherapy (in conjunction with metformin) in patients with type 2 diabetes and established atherosclerotic heart disease, heart failure or chronic kidney disease due to their favourable effects on cardiovascular and renal outcomes. We report a case of a 69-year-old man who developed muscle pain, weakness and wasting after commencing the SGLT2 inhibitor empagliflozin. This persisted for 1 year before he underwent resistance testing, which confirmed muscle weakness. His symptoms resolved within weeks of ceasing empagliflozin, with improvement in muscle strength on clinical assessment and resistance testing and reversal of MRI changes. No other cause of myopathy was identified clinically, on biochemical assessment or imaging, suggesting that empagliflozin was the cause of his myopathy.

LEARNING POINTS

Empagliflozin, a commonly used SGLT2 inhibitor, was associated with myopathy. A high degree of suspicion is required to diagnose drug-induced myopathy, with a temporal relationship between starting the medication and symptom onset being the main indicator. Recognition of drug-induced myopathy is essential, as discontinuation of the offending drug typically improves symptoms.

Waddling Gait: A complication of valproate therapy and a thought beyond vitamin D deficiency

Proximal muscle weakness is a common presentation in paediatric-orthopaedic clinics and is frequently paired with a vitamin D deficiency diagnosis. Recently, side effects of the extensive use of antiepileptic and antipsychotic drugs such as sodium valproate in childhood disorders are being documented. Sodium valproate causes a time-dependent, drug-induced proximal myopathy. We report a 13-year-old female patient who presented at the Orthopaedic Outpatient Department at Lady Hardinge Medical College, New Delhi, India, in 2019 with an abnormal gait. The patient was taking a combination therapy of sodium valproate, risperidone and trihexyphenidyl for absence seizures and a mood disorder. Following clinical investigations, the patient was diagnosed with proximal myopathy. As a result of elevated serum alkaline phosphatase and creatine kinase myocardial band levels, sodium valproate was replaced with ethosuximide and a carnitine supplementation was prescribed. The patient fully recovered and regained full mobility. Proximal myopathy had been incorrectly managed and assumed to be caused by a vitamin D deficiency.

A super-combo-drug test to detect adverse drug events and drug interactions from electronic health records in the era of polypharmacy

Pharmacoinformatics research has experienced a great deal of successes in detecting drug-induced adverse events (AEs) using large-scale health record databases. In the era of polypharmacy, pharmacoinformatics faces many new challenges, and two significant challenges are to detect high-order drug interactions and to handle strongly correlated drugs. In this article, we propose a super-combo-drug test (SupCD-T) to address the aforementioned two challenges. SupCD-T detects drug interactions by identifying optimal drug combinations with increased AE risks. In addition, SupCD-T increases the statistical powers to detect single-drug effects by combining strongly correlated drugs. Although SupCD-T does not distinguish single-drug effects from their combination effects, it is noticeably more powerful in selecting an individual drug effect in the multiple regression analysis, where confounding justification between two correlated drugs reduces the power in testing the individual drug effects on AEs. Our simulation studies demonstrate that SupCD-T has generally better power comparing with the multiple regression analysis. In addition, SupCD-T is able to select meaningful drug combinations (eg, highly coprescribed drugs). Using electronic health record database, we illustrate the utility of SupCD-T and discover a number of drug combinations that have increased risk in myopathy. Some novel drug combinations have not yet been investigated and reported in the pharmacology research.

Long acting GLP-1 analog liraglutide ameliorates skeletal muscle atrophy in rodents

BACKGROUND

Skeletal muscle atrophy is characterized by muscle wasting with partial or complete functional loss. Skeletal muscle atrophy severely affects the quality of life and currently, there is no available therapy except for spinal muscular atrophy.

OBJECTIVE

Drug repositioning is a promising strategy that reduces cost and time due to prior availability of safety and toxicity details. Here we investigated myogenic and anti-atrophy effects of glucagon-like peptide-1 (GLP-1) analog liraglutide.

METHODS

We used several in vitro atrophy models in C2C12 cells and in vivo models in Sprague Dawley rats to study Liraglutide's efficacy. Western blotting was used to assess cAMP-dependent signaling pathways specifically activated by liraglutide. Therapeutic efficacy of liraglutide was investigated by histological analysis of transverse muscle sections followed by morphometry. Myogenic capacity was investigated by immunoblotting for myogenic factors.

RESULTS

Liraglutide induced myogenesis in C2C12 myoblasts through GLP-1 receptor via a cAMP-dependent complex network of signaling events involving protein kinase A, phosphoinositide 3-kinase/protein kinase B, p38 mitogen-activated protein kinase and extracellular signal-regulated kinase. Liraglutide imparted protection against freeze injury, denervation, and dexamethasone -induced skeletal muscle atrophy and improved muscular function in all these models. In a therapeutic model, liraglutide restored myofibrillar architecture in ovariectomy-induced atrophy. Anti-atrophy actions of liraglutide involved suppression of atrogene expression and enhancement in expression of myogenic factors.

CONCLUSION

Liraglutide imparted protection and restored myofibrillar architecture in diverse models of muscle atrophy. Given its potent anti-atrophy, and recently reported osteoanabolic effects, we propose liraglutide's clinical evaluation in skeletal muscle atrophy and musculoskeletal disorders associated with diverse pathologies.

Myositis Induced by Isotretinoin: A Case Report and Literature Review

Patient: Male, 45-year-old

Final Diagnosis: Myositis induced by isotretinoin

Symptoms: Muscle pain in the upper limbs with marked functional limitation associated by coluria

Medication: —

Clinical Procedure: —

Specialty: Rheumatology

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.

A pilot study on the association between SLCO1B1 RS4363657 polymorphism and muscle adverse events in adults with newly diagnosed dyslipidaemia who were prescribed a statin: the Malaysian primary health care cohort

Introduction: Statin, the first-line treatment for dyslipidaemia, may have suboptimal adherence due to its associated muscle adverse events. These data, however, remain limited. Aim: To determine the association of serum creatine kinase (CK) and SLCO1B1 rs4363657 polymorphism with statin-associated muscle adverse events (SAMAE) among dyslipidaemia participants. Methods: This was a prospective cohort study at government health clinics involving newly diagnosed adults with dyslipidaemia. SAMAE were recorded based on the patient's complaint after a month on statin. CK was taken at baseline and follow-up. Genetic profiling was performed for SLCO1B1 rs4363657 polymorphism. Results: Among 118 participants, majority were Malay (72%) males (61%) with a mean age of 49 ± 12.2 years old and prescribed lovastatin (61.9). There was a significant association between statin types (lovastatin and simvastatin) and SAMAE (p = 0.0327); no significant association noted between CK and SAMAE (p = 0.5637). The SLCO1B1 rs4363657 polymorphism was significantly associated SAMAE (p < 0.0001). Conclusions: In this first pilot study of a multiethnic Malaysian population, the incidence of SAMAE was 18.6%. SAMAE were significantly higher in subjects on lovastatin compared to simvastatin. SLCO1B1 rs4363657 polymorphism was a significant risk factor for SAMAE.

Modeling the Effect of TNF-α upon Drug-Induced Toxicity in Human, Tissue-Engineered Myobundles

A number of significant muscle diseases, such as cachexia, sarcopenia, systemic chronic inflammation, along with inflammatory myopathies share TNF-α-dominated inflammation in their pathogenesis. In addition, inflammatory episodes may increase susceptibility to drug toxicity. To assess the effect of TNF-α-induced inflammation on drug responses, we engineered 3D, human skeletal myobundles, chronically exposed them to TNF-α during maturation, and measured the combined response of TNF-α and the chemotherapeutic doxorubicin on muscle function. First, the myobundle inflammatory environment was characterized by assessing the effects of TNF-α on 2D human skeletal muscle cultures and 3D human myobundles. High doses of TNF-α inhibited maturation in human 2D cultures and maturation and function in 3D myobundles. Then, a tetanus force dose-response curve was constructed to characterize doxorubicin's effects on function alone. The combination of TNF-α and 10 nM doxorubicin exhibited a synergistic effect on both twitch and tetanus force production. Overall, the results demonstrated that inflammation of a 3D, human skeletal muscle inflammatory system alters the response to doxorubicin.

Voriconazole-induced Myositis in a Double Lung Transplant Recipient

Voriconazole is a triazole antifungal agent commercially approved in 2002. It is commonly used in immunocompromised patients as a therapeutic and prophylactic agent. We present the case of a 26-year-old Caucasian female who is a double lung transplant recipient who presented with complaints of generalized left lower extremity swelling and extreme tenderness of her left thigh. Although her muscle enzymes were not significantly elevated, inflammatory changes were noticed on T2-weighted fat-suppressed short-TI inversion recovery (STIR) sequence magnetic resonance imaging (MRI). These findings were later confirmed with tissue biopsy. We hereby present the case of drug-induced myositis as a rare complication of voriconazole used as chemoprophylaxis in a double lung transplant recipient patient.

New perspectives on dry needling following a medical model: are we screening our patients sufficiently?

Myofascial trigger points are not an isolated neuromusculoskeletal phenomenon and have been implicated in systemic, visceral, and metabolic pathology, as a side effect of some medications and in the presence of psychological risk factors. This complexity can complicate adequate screening of patients prior to choosing dry needling as a treatment intervention. Regardless of whether clinicians practice in a direct access setting, they should be cognizant of medical conditions, comorbidities, and risk factors that will influence clinical decisions for dry-needling appropriateness, technique chosen, and potential adverse responses to treatment. Of primary concern are conditions that can either manifest with myalgia and/or myopathy or masquerade as a more common musculoskeletal condition. This clinical commentary reviews system-specific considerations and other common disorders that should be screened for and discusses not only whether dry needling is appropriate but comments on technique and dosage considerations when initiating dry needling.

Plasma 2-hydroxyglutarate, a promising prognostic biomarker candidate for skeletal muscle injury in Fischer 344 rats

Previously, we have demonstrated the potential of plasma 2-hydroxyglutarate (2HG) as an easily detectable biomarker for skeletal muscle injury in rats. Here, we examined whether plasma 2HG was superior to conventional skeletal muscle damage biomarkers, including aspartate aminotransferase (AST), creatine kinase (CK), and skeletal muscle-type CK isoenzyme (CK-MM) levels, in rats. Skeletal muscle injury was induced in 4- or 9-week-old male Fischer 344 rats by cerivastatin (CER) or tetramethyl-p-phenylenediamine (TMPD) administration. Plasma 2HG levels were measured on days 4, 8, and 11 (CER group) and at 6 and 24 hr post-administration (TMPD group). Plasma AST, CK, and CK-MM activities and histopathological changes in the rectus femoris muscle were evaluated at the study endpoints. In the CER group, AST, CK, and CK-MM increased in 4- and 9-week-old rats, whereas increases in CK (4- and 9-week-old rats) and CK-MM (4-week-old rats) were not obvious in the TMPD group. In both 4- and 9-week-old rats, plasma 2HG increased on day 8 and at 24 hr post-administration in the CER and TMPD groups, respectively. Histopathological analysis revealed myofiber vacuolation and necrosis in both groups. The histopathological damage to the rectus femoris muscle was more severe in the CER than in the TMPD group. Increased plasma 2HG was associated with CER- and TMPD-induced skeletal muscle injuries in rats and was not affected by age differences or repeated blood collection. The results suggest that plasma 2HG is superior to CK and CK-MM as a biomarker for mild skeletal muscle injury.

Skeletal Muscle Injury Biomarkers: Assay Qualification Efforts and Translation to the Clinic

Skeletal muscle (SKM) injury or myopathy results in structural or functional defects in SKMs that can be caused by variety of factors such as (1) genetic, (2) drug-induced, (3) disease progression (cachexia), or (4) aging (sarcopenia). Creatine kinase (CK) and aspartate transaminase (AST) activity assays have been routinely used as SKM injury biomarkers, but they lack sensitivity and tissue specificity. In collaboration with the Predictive Safety Testing Consortium, we evaluated the diagnostic performance of a muscle injury biomarker panel (MIP) compared to CK and AST and their correlation with the histology scores across 34 different rat studies. The MIP panel included the analytes skeletal troponin I, myosin light chain 3, fatty acid binding protein 3, and a CK mass (versus activity) assay. The area under the receiver operator characteristic curve for MIP panel ranged from 0.82 to 0.91 as compared to 0.71 and 0.82 for CK and AST activity assays, respectively. Because the MIP biomarkers outperformed the routine biomarkers, the European Medicines Agency and U.S. Food and Drug Administration posted Letters of Support encouraging further study of these analytes and acknowledged the utility of the MIP panel. Ongoing efforts are directed toward the application of the MIP panel biomarkers in clinical studies and regulatory qualification.

MR Imaging of Atraumatic Muscle Disorders

Atraumatic disorders of skeletal muscles include congenital variants; inherited myopathies; acquired inflammatory, infectious, or ischemic disorders; neoplastic diseases; and conditions leading to muscle atrophy. These have overlapping appearances at magnetic resonance (MR) imaging and are challenging for the radiologist to differentiate. The authors organize muscle disorders into four MR imaging patterns: (a) abnormal anatomy with normal signal intensity, (b) edema/inflammation, (c) mass, and (d) atrophy, highlighting each of their key clinical and imaging findings. Anatomic muscle variants, while common, do not produce signal intensity alterations and therefore are easily overlooked. Muscle edema is the most common pattern but is nonspecific, with a broad differential diagnosis. Autoimmune, paraneoplastic, and drug-induced myositis tend to be symmetric, whereas infection, radiation-induced injury, and myonecrosis are focal asymmetric processes. Architectural distortion in the setting of muscle edema suggests one of these latter processes. Intramuscular masses include primary neoplasms, metastases, and several benign masslike lesions that simulate malignancy. Some lesions, such as lipomas, low-flow vascular malformations, fibromatoses, and subacute hematomas, are distinctive, but many intramuscular masses ultimately require a biopsy for definitive diagnosis. Atrophy is the irreversible end result of any muscle disease of sufficient severity and is the dominant finding in disorders such as the muscular dystrophies, denervation myopathy, and sarcopenia. This imaging-based classification, in correlation with clinical and laboratory data, will aid the radiologist in interpreting MR imaging findings in patients with atraumatic muscle disorders. ^©RSNA, 2018.

ERS International Congress 2017: a peek of outstanding abstracts from the clinical assembly

This review highlights a selection of abstracts from the 2017 ERS International Congress in Milan presented by the clinical assembly's groups of interventional pulmonology, general practice and primary care and rehabilitation and chronic care. Attention is brought to the increasing burden of disease of COPD and end-stage emphysema patients in China. The considerable efforts of Chinese pulmonary centers to conduct multicenter, randomized and controlled trials, investigating the possibilities of bronchoscopic lung volume reduction is underlined in the review. Furthermore, the key objectives of asthma management are stressed. We point out presentations emphasizing on achieving good control of daily symptoms and reducing the risk of asthma exacerbations. The findings of a randomized clinical trial evaluating the role of oxygen supplementation in rehabilitation therapy of COPD patients are analyzed. Additionally, another randomized clinical trial researching the influence of whole body vibration training (WBVT) in long-term (>1 year) lung transplant patients are discussed.

Study of Statin- and Loratadine-Induced Muscle Pain Mechanisms Using Human Skeletal Muscle Cells

Many drugs can cause unexpected muscle disorders, often necessitating the cessation of an effective medication. Inhibition of monocarboxylate transporters (MCTs) may potentially lead to perturbation of l-lactic acid homeostasis and muscular toxicity. Previous studies have shown that statins and loratadine have the potential to inhibit l-lactic acid efflux by MCTs (MCT1 and 4). The main objective of this study was to confirm the inhibitory potentials of atorvastatin, simvastatin (acid and lactone forms), rosuvastatin, and loratadine on l-lactic acid transport using primary human skeletal muscle cells (SkMC). Loratadine (IC₅₀ 31 and 15 µM) and atorvastatin (IC₅₀ ~130 and 210 µM) demonstrated the greatest potency for inhibition of l-lactic acid efflux at pH 7.0 and 7.4, respectively (~2.5-fold l-lactic acid intracellular accumulation). Simvastatin acid exhibited weak inhibitory potency on l-lactic acid efflux with an intracellular lactic acid increase of 25–35%. No l-lactic acid efflux inhibition was observed for simvastatin lactone or rosuvastatin. Pretreatment studies showed no change in inhibitory potential and did not affect lactic acid transport for all tested drugs. In conclusion, we have demonstrated that loratadine and atorvastatin can inhibit the efflux transport of l-lactic acid in SkMC. Inhibition of l-lactic acid efflux may cause an accumulation of intracellular l-lactic acid leading to the reported drug-induced myotoxicity.

Peripheral Muscle Strength Indicates Respiratory Function Testing in Renal Recipients

OBJECTIVES

Muscle wasting occurs in renal recipients due to decreased physical performance, and decreased respiratory muscle strength may occur due to changes in structure and function. Data are scarce regarding the roles of sarcopenia and nutritional status on respiratory muscle function in these patients. Here, we evaluated interactions among peripheral muscle strength, sarcopenia, nutritional parameters, and respiratory muscle function in renal transplant recipients.

MATERIALS AND METHODS

Ninety-nine patients were prospectively enrolled between September and April 2016 at Baskent University. Forced vital capacity values (via pulmonary function tests), respiratory muscle strength (via maximal static inspiratory and expiratory pressures), and peripheral muscle strength (via hand grip strength test) were recorded. Nutritional parameters, fat weight, arm circumference, waist circumference, and C-reactive protein levels were also recorded.

RESULTS

Of 99 patients, 68 were renal transplant recipients (43 men, mean age: 39.09 ± 10.70 y) and 31 were healthy participants (14 men, mean age: 34.94 ± 10.95 y). Forced vital capacity (P < .001, r = 0.65), maximal inspiratory (P = .002, r = 0.39) and expiratory (P < .001, r = 0.4) pressure, and hand grip strength showed significant relations in transplant recipients. Positive correlations were found between serum albumin levels and both hand grip strength (P = .16, r = 0.347) and forced vital capacity (P = .03, r = 0.436). Forced vital capacity was statistically different between renal recipients and healthy participants (P = .013), whereas maximal inspiratory and expiratory pressures were not (P > .05). No statistically significant relation was observed between biochemical parameters and maximal inspiratory and expiratory pressures (P ? .05).

CONCLUSIONS

Respiratory function and peripheral muscle strength were significantly related in renal transplant recipients, with significantly lower peripheral muscle strength suggesting the presence of inadequate respiratory function. Peripheral and respiratory muscle training and nutritional replacement strategies could help to improve postoperative respiratory function.

Human, Tissue-Engineered, Skeletal Muscle Myobundles to Measure Oxygen Uptake and Assess Mitochondrial Toxicity

Mitochondrial dysfunction is responsible for the toxicity of a number of drugs. Current isolated mitochondria or cellular monoculture mitochondrial respiration measurement systems lack physiological relevance. Using a tissue engineering rather than cell- or mitochondria-based approach enables a more physiologically relevant detection of drug-induced mitochondrial impairment. To probe oxygen consumption and mitochondrial health, we assayed the bioenergetic profile of engineered three-dimensional human skeletal muscle myobundles derived from primary myoblasts. Through experimental and computational techniques, we did not find external or internal oxygen transport limiting the engineered myobundles in the commercial O2k system to measure oxygen consumption. In response to the complex I inhibitor rotenone, myobundle basal respiration decreased dose dependently with an IC₅₀ of 9.24 ± 0.03 nM. At a 20 nM concentration of rotenone, myobundle maximal respiration decreased by 44.4% ± 9.8%. Respiratory depression by rotenone suggests that cultured myobundles rely heavily on the complex I pathway for ATP synthesis during times of both basal and increased energy demand. To address whether these decrements in mitochondrial function corresponded to alterations in physiological muscle function, we determined fatigue susceptibility that revealed a 46.0% ± 7.4% depression at 20 nM rotenone. The bioenergetic health index, which is a measure of normal oxidative mitochondrial function, was inversely correlated with the extent of fatigue. The human myobundles reproduce normal muscle metabolism under both basal and maximal energy demand conditions enabling the detection of drug-induced mitochondrial toxicity.

Acute Generalized Weakness

Weakness is a common complaint in the emergency department, and a most challenging one, because before the emergency physician can proceed with an evaluation, the complaint of weakness must be fully clarified to determine about what the patient is actually complaining. This article will focus on causes of acute generalized nontraumatic bilateral weakness. Evaluation begins with the history and physical examination, followed by diagnostic testing in some cases.