Search

Statins are the first line of treatment for both primary and secondary prevention of atherosclerotic cardiovascular disease. Despite the positive effects of statins on cardiovascular events, not all patients can use them at an optimized dose. The reason for this is the skeletal muscle side effects, termed statin‐associated muscle symptoms (SAMS). Despite extensive research, the precise pathophysiology of SAMS remains unclear and multiple mechanisms may contribute to this phenomenon. Various therapeutic options are available for the management of SAMS, ranging from rechallenging with the same or a different statin to utilizing non‐statin therapeutic alternatives in patients intolerant to statins. However, the lack of consensus on the definition of SAMS, the absence of a definitive diagnostic test, and lack of a universally accepted management algorithm pose a great challenge in dealing with this entity. This review aims to explore the various pathophysiological mechanisms involved in SAMS and understand the difference between self‐limited toxic myopathy and immune‐mediated myopathy requiring immunomodulatory therapy. The conundrum of statin withdrawal, tapering, and rechallenge in SAMS will also be explored in detail along with the newer non‐statin therapies that are available. [ABSTRACT FROM AUTHOR]

The new coronavirus infection (COVID-19) is associated with a wide spectrum of various clinical manifestations including involvement of the musculoskeletal system which can persist for a long time after the infection. Supposedly, pathogenesis of musculoskeletal manifestations of COVID-19 is primarily caused by systemic inflammation accompanied by cytokine hyperexpression (interferon γ, interleukins 1β, 6, 8, 17, tumor necrosis factor α), as well as hypoxia leading to overproduction of inflammatory cytokines, activation of bone reabsorption by osteoclasts and subsequent decrease of mineral bone density and osteonecrosis in some cases. Additionally, some drugs prescribed to patients with COVID-19 (some antiviral drugs and glucocorticoids) should also be taken into account as they can lead to development of musculoskeletal pathology. In the acute period of COVID-19, myalgias are common, but in rare cases myositis with proximal muscular weakness and increased levels of creatine phosphokinase, lactate dehydrogenase can occur. Arthralgias in the acute period of COVID-19 are rarer than myalgias. In the studies of clinical manifestation of COVID-19, frequency of arthralgias and myalgias in the acute period is between 15.5 and 50 %. After COVID-19, frequency of arthralgias and myalgias gradually decreases, however there are cases of long-term joint and muscle pains, as well as post-viral arthritis, development of arthritis in the context of various autoimmune disorders. Myalgias and arthralgias during COVID-19 usually regress spontaneously and in most patients do not require prescription of antipain medications, but in some cases pain management is necessary. Use of non-steroid anti-inflammatory drugs and vitamin D during COVID-19 is a safe and effective method of pain management, including myalgia and arthralgia. Rehabilitation programs play an important role in improvement of functional state and patient recovery after moderate and severe COVID-19.

Nrf2 (nuclear factor [erythroid-derived 2]-like 2; the transcriptional master regulator of the antioxidant stress response) is regulated through interaction with its cytoplasmic inhibitor Keap1 (Kelch-like ECH-associated protein 1), which under basal conditions targets Nrf2 for proteasomal degradation. Sequestosome 1 (SQSTM1)/p62-a multifunctional adapter protein that accumulates following autophagy inhibition and can serve as a diagnostic marker for human autophagic vacuolar myopathies (AVMs)-was recently shown to compete with Nrf2 for Keap1 binding, resulting in activation of the Nrf2 pathway. In this study, we used 55 human muscle biopsies divided into five groups [normal control, hydroxychloroquine- or colchicine-treated non-AVM control, hydroxychloroquine- or colchicine-induced toxic AVM, polymyositis, and inclusion body myositis (IBM)] to evaluate whether Keap1-SQSTM1 interaction led to increased Nrf2 signaling in human AVMs. In toxic AVMs and IBM, but not in control muscle groups or polymyositis, Keap1 antibody labeled sarcoplasmic protein aggregates that can be used as an alternate diagnostic marker for both AVM types; these Keap1-positive aggregates were co-labeled with the antibody against SQSTM1 but not with the antibody against autophagosome marker LC3 (microtubule-associated protein 1 light chain 3). In human AVM muscle, sequestration of Keap1 into the SQSTM1-positive protein aggregates was accompanied by an increase in mRNA and protein levels of Nrf2 target genes; similarly, treatment of differentiated C2C12 myotubes with autophagy inhibitor chloroquine led to an increase in the nuclear Nrf2 protein level and an increase in expression of the Nrf2-regulated genes. Taken together, our findings demonstrate that Nrf2 signaling is upregulated in autophagic muscle disorders and raise the possibility that autophagy disruption in skeletal muscle leads to dysregulation of cellular redox homeostasis.

Abstract Background Hypoglycin A (HGA) intoxication after ingestion of Acer spp. tree material has never been confirmed in domesticated ruminants despite their similar grazing habitats. Objectives To investigate whether sheep have low HGA bioavailability caused by rumen HGA breakdown. Animals Stomach and rumen fluid samples from 5 adult horses and 5 adult sheep respectively. Residual serum samples from 30 ewes and lambs. Methods Experimental and retrospective cohort study. Hypoglycin A concentration was quantified in horse gastric and sheep ruminal samples after in vitro incubation with Acer pseudoplatanus seeds. Serum samples from grazing sheep (n = 20) and nursing lambs (n = 10) obtained before and after their release onto pastures with and without Sycamore seedlings were analyzed for HGA and methylenecyclopropyl‐acetic acid carnitine, and serum biochemistry. Results Neither ovine rumen nor equine gastric fluid affected HGA content in samples incubated for up to 2 hours. Despite HGA's detection in serum from sheep (n = 13/15; median, 23.71 ng/mL; range, 5.62‐126.4 ng/mL) grazing contaminated pastures and in their nursing lambs (n = 2/5; median, 12.5 ng/mL; range, 8.82‐15.67 ng/mL), there was no apparent clinical or subclinical disease. Conclusions and Clinical Importance Any reduced sensitivity to HGA intoxication in sheep seems unrelated to ruminal degradation. Serum HGA concentrations in sheep were similar to those of subclinically affected atypical myopathy horses. Any reduced sensitivity of sheep to HGA might be related to greater metabolic resistance rather than selective grazing habits or lower bioavailability. Hypoglycin A was found in nursing lambs, suggesting that HGA is excreted in milk.

ABSTRACT: Monensin is an ionophore antibiotic (IA) widely used for growth promotion and weight gain in the production of ruminants. However, it has caused intoxication in several species, including buffaloes, mainly because of the ignorance or disrespect of the recommendations for use in each animal species. The objective of this study was to describe, for the first time, clinical-epidemiological and anatomopathological data of an outbreak of accidental poisoning by monensin in buffalos and rediscuss the recommendation of the use of IA in the production of this species. The outbreak affected 21 adult buffaloes after consumption of remains from a feed formulated on the farm and whose constituents were mixed by hand. Clinical and first death signs were observed 24 hours after ingestion of this food. In general, the clinical picture was characterized by muscle weakness, tremors, difficulty in locomotion, and decubitus. Fifteen buffaloes presented clinical signs of poisoning (71.5% morbidity), followed by death (100% lethality), after acute to subacute evolution (

Chloroquine (CQ) and hydroxychloroquine (HCQ) have been associated with muscle toxicity, mostly described as a proximal myopathy with evidence of lysosomal dysfunction on muscle biopsy. In this retrospective study, we aimed to define the clinical phenotype, laboratory features, and treatment outcomes of CQ/HCQ myopathy, as well as the safety profile of these drugs. We identified 13 patients seen between 2000 and 2019, with a median age at presentation of 66 years (range 53–89); 11 were females. At onset of symptoms, patients were on CQ or HCQ for a minimum of 6 months and up to 21 years. Diagnosis was often delayed by a median of 6 months (range 3–48). At presentation, 13 patients reported limb weakness, with five requiring assistance in walking. Ten reported dysphagia, often severe, resulting in marked weight loss or aspiration pneumonia. Nine reported respiratory symptoms, which were multifactorial in four, and four reported severe neck weakness. Myopathy clinical phenotype showed predominant involvement of one or more of the following: proximal limb muscle weakness (12 patients), dysphagia (9), axial weakness (4), and respiratory failure (5). Eleven patients had a cardiac evaluation showing prolonged QT interval in 10 and CQ/HCQ cardiomyopathy (CMP) in four. Ten out of 12 patients markedly improved after discontinuing the medication, but most were left with some residual weakness. Eleven patients had a muscle biopsy showing a myopathy with rimmed vacuoles and marked acid phosphatase reactivity. Nine had elevated creatine kinase level up to 1,199 U/L. Twelve patients had an electromyography (EMG), which showed myopathic motor unit potentials with fibrillation potentials in 11 and myotonic discharges in 3. Higher cumulative dose and longer exposure duration were associated with more severe disability and more common cardiac and swallow involvement, indicating a cumulative dose effect. Herein, we demonstrate that long-term exposure to CQ and HCQ may result in a myopathy with a wide spectrum of clinical presentation and predilection for swallowing, respiratory, and cardiac muscles, often with marked associated morbidity. Once accurately diagnosed and the drug is discontinued, patients usually improve but often fail to return to baseline.

Background: Hypoglycin A (HGA) intoxication after ingestion of Acer spp. tree material has never been confirmed in domesticated ruminants despite their similar grazing habitats. Objectives: To investigate whether sheep have low HGA bioavailability caused by rumen HGA breakdown. Animals Stomach and rumen fluid samples from 5 adult horses and 5 adult sheep respectively. Residual serum samples from 30 ewes and lambs. Methods: Experimental and retrospective cohort study. Hypoglycin A concentration was quantified in horse gastric and sheep ruminal samples after in vitro incubation with Acer pseudoplatanus seeds. Serum samples from grazing sheep (n = 20) and nursing lambs (n = 10) obtained before and after their release onto pastures with and without Sycamore seedlings were analyzed for HGA and methylenecyclopropyl‐acetic acid carnitine, and serum biochemistry. Results: Neither ovine rumen nor equine gastric fluid affected HGA content in samples incubated for up to 2 hours. Despite HGA's detection in serum from sheep (n = 13/15; median, 23.71 ng/mL; range, 5.62‐126.4 ng/mL) grazing contaminated pastures and in their nursing lambs (n = 2/5; median, 12.5 ng/mL; range, 8.82‐15.67 ng/mL), there was no apparent clinical or subclinical disease. Conclusions and Clinical Importance: Any reduced sensitivity to HGA intoxication in sheep seems unrelated to ruminal degradation. Serum HGA concentrations in sheep were similar to those of subclinically affected atypical myopathy horses. Any reduced sensitivity of sheep to HGA might be related to greater metabolic resistance rather than selective grazing habits or lower bioavailability. Hypoglycin A was found in nursing lambs, suggesting that HGA is excreted in milk. [ABSTRACT FROM AUTHOR]

Introduction: This Perspective reassesses the consensus opinion that statin-associated muscle symptoms (SAMS) occur in <1% of users and associated myopathic proximal muscle weakness is even more rare. Areas covered: Of the over 180,000 participants in clinical trials and large registries of statin users, only a few studies have included a standard manual muscle test (MMT), dynamometry or a focused questionnaire to assess for proximal weakness and related disability in daily and recreational activities. Formal strength testing suggests, however, that weakness can be demonstrated in at least 10% of users. Expert opinion: Reporting inaccuracies about SAMS, confirmation bias among experts and physicians, absence of a standard questionnaire regarding the potential consequences of weakness on physical capacity, and the failure to routinely perform an objective assessment of strength may have led to under-diagnosis of statin-induced myopathy. A brief MMT before cholesterol-lowering agents are started and at follow-up visits, a 12-week withdrawal of the statin in the presence of new paresis without an alternative cause, and the exam finding that strength recovers off the statin are necessary to assess the incidence of drug-induced proximal weakness and inform alternative therapeutic strategies. [ABSTRACT FROM AUTHOR]

Chloroquine (CQ) and hydroxychloroquine (HCQ) have been associated with muscle toxicity, mostly described as a proximal myopathy with evidence of lysosomal dysfunction on muscle biopsy. In this retrospective study, we aimed to define the clinical phenotype, laboratory features, and treatment outcomes of CQ/HCQ myopathy, as well as the safety profile of these drugs. We identified 13 patients seen between 2000 and 2019, with a median age at presentation of 66 years (range 53–89); 11 were females. At onset of symptoms, patients were on CQ or HCQ for a minimum of 6 months and up to 21 years. Diagnosis was often delayed by a median of 6 months (range 3–48). At presentation, 13 patients reported limb weakness, with five requiring assistance in walking. Ten reported dysphagia, often severe, resulting in marked weight loss or aspiration pneumonia. Nine reported respiratory symptoms, which were multifactorial in four, and four reported severe neck weakness. Myopathy clinical phenotype showed predominant involvement of one or more of the following: proximal limb muscle weakness (12 patients), dysphagia (9), axial weakness (4), and respiratory failure (5). Eleven patients had a cardiac evaluation showing prolonged QT interval in 10 and CQ/HCQ cardiomyopathy (CMP) in four. Ten out of 12 patients markedly improved after discontinuing the medication, but most were left with some residual weakness. Eleven patients had a muscle biopsy showing a myopathy with rimmed vacuoles and marked acid phosphatase reactivity. Nine had elevated creatine kinase level up to 1,199 U/L. Twelve patients had an electromyography (EMG), which showed myopathic motor unit potentials with fibrillation potentials in 11 and myotonic discharges in 3. Higher cumulative dose and longer exposure duration were associated with more severe disability and more common cardiac and swallow involvement, indicating a cumulative dose effect. Herein, we demonstrate that long-term exposure to CQ and HCQ may result in a myopathy with a wide spectrum of clinical presentation and predilection for swallowing, respiratory, and cardiac muscles, often with marked associated morbidity. Once accurately diagnosed and the drug is discontinued, patients usually improve but often fail to return to baseline. [ABSTRACT FROM AUTHOR]

Hydroxychloroquine is being used for COVID‐19 symptoms and in clinical trials, but can cause a toxic myopathy that leads to muscle weakness. A review of skeletal muscle biopsies from patients with hydroxychloroquine myopathy gives pointers of steps that can be taken to diagnose this toxic myopathy early and help differentiate it from COVID‐19‐related muscle weakness. [ABSTRACT FROM AUTHOR]

Boxelder and sycamore maple contain hypoglycin A (HGA), the toxic metabolite of which, MCPA-CoA, inhibits fatty acid β-oxidation, causing seasonal pasture myopathy (SPM) or atypical myopathy (AM), respectively. White snakeroot and rayless goldenrod contain multiple benzofuran ketones (BFKs). The identity/toxicity of BFKs appear variable, possibly involving interactions between toxins/toxic metabolites, but ultimately inhibit cellular energy metabolism. Unthrifty horses grazing sparse pastures during the fall appear predisposed to these plant-associated, frequently fatal, toxic myopathies. Toxidromes are characterized by varying degrees of rhabdomyolysis and cardiac myonecrosis, with plant toxins remaining toxic in hay and being excreted in milk., Competing Interests: Disclosures The authors have no disclosures., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Summary: Background: Several pasture management strategies have been proposed to avoid hypoglycin A (HGA) intoxication in horses, but their efficacy has never been investigated. Objectives: To evaluate the effect of mowing and herbicidal spraying on HGA content of sycamore seedlings and the presence of HGA in seeds and seedlings processed within haylage and silage. Study design: Experimental study. Methods: Groups of seedlings were mowed (n = 6), sprayed with a dimethylamine‐based (n = 2) or a picolinic acid‐based herbicide (n = 1). Seedlings were collected before intervention, and at 48 h, 1 and 2 weeks after. Cut grass in the vicinity of mowed seedlings was collected pre‐cutting and after 1 week. Seeds and seedling (n = 6) samples processed within haylage and silage were collected. HGA concentration in samples was measured using a validated LC‐MS‐based method. Results: There was no significant decline in HGA content in either mowed or sprayed seedlings; indeed, mowing induced a temporary significant rise in HGA content of seedlings. HGA concentration increased significantly (albeit to low levels) in grass cut with the seedlings by 1 week. HGA was still present in sycamore material after 6–8 months storage within either hay or silage. Main limitations: Restricted number of herbicide compounds tested. Conclusions: Neither mowing nor herbicidal spraying reduces HGA concentration in sycamore seedlings up to 2 weeks after intervention. Cross contamination is possible between grass and sycamore seedlings when mowed together. Mowing followed by collection of sycamore seedlings seems the current best option to avoid HGA toxicity in horses grazing contaminated pasture. Pastures contaminated with sycamore material should not be used to produce processed hay or silage as both seedlings and seeds present in the bales still pose a risk of intoxication. [ABSTRACT FROM AUTHOR]

Ionophore antibiotics (IA) are drugs used in animals, particularly as coccidiostats and growth promoters. They can cause acute or chronic poisoning, inducing skeletal and / or heart muscle injuries. This paper describes the epidemiological, clinical and pathological aspects of an IA poisoning outbreak in sheep and cattle fed with leftovers from a animal ration factory. Four hours after the access to the contaminated feed, some sheep were found dead and several others were sick. The cattle manifested clinical signs one day after ingestion of the feed, with death 4 to 20 days after clinical onset. The signs consisted of inappetence, weakness, reluctance to move, incoordination, dyspnea, lateral decubitus and death. Of the sheep herd 61 (42.36%), and eight young cattle (24.24% of the lot) died. Two sick sheep were sent to the Veterinary Pathology Sector, Department of Veterinary Medicine of the Federal University of Lavras (SPV/DMV/UFLA). Due to the severity of the clinical condition, both were euthanized. At necropsy were observed pale areas in the muscles, characterized histologically by varying degrees of necrosis and regeneration in skeletal and cardiac muscles. It was performed a chromatographic analysis (HPLC) of a sample of feed, which showed 97.14 mg monensin/kg of feed. The diagnosis was based on epidemiological, clinical, gross and histological findings, and toxicological analysis of the feed used. Although the use of "scan feed mill" seems an economically attractive option for producers it presents risks and is not recommended.

Clinically identified myopathies can occur with administration of medications such as statins, glucocorticoids, antibiotics, antirheumatics, and retinoids. While the frequency of drug-induced myopathies is unclear, they are an important group of disorders in anyone presenting with muscular symptoms and should be considered in patients with symptoms ranging from mild myalgia or muscle cramping to profound muscle weakness without a known etiology. Certain medications are commonly associated with myopathy and frequently prescribed (glucocorticoids, statins); a few are more likely to occur with exercise, whereas others have myopathy as a rare side effect. Developing a greater understanding of underlying mechanisms and symptoms of drug-induced myopathy can promote enhanced awareness, early recognition, and improved patient care because many drug-induced myopathies are potentially reversible at early stages. [ABSTRACT FROM AUTHOR]

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Corticosteroid-induced myopathy is the most common drug-induced myopathy and could appear during the treatment of diseases where corticosteroids are the mainstay of treatment. We present a clinical case of a patient treated with corticosteroids who presented with proximal muscle weakness, myalgias, marked elevation of muscle enzymes, and acute kidney injury due to rhabdomyolysis. The definitive diagnosis was only possible through a muscle biopsy., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Coutinho et al.)

An outbreak of salinomycin poisoning in rabbits is described. At least 27 out of 2,000 rabbits reared on a farm died after the coccidiostatic drug sulfaquinoxaline was substituted by salinomycin in the feed. An average of 26.9ppm salinomycin was detected in the ration given to the rabbits. Clinical signs included anorexia, apathy and bradykinesia, which progressed to incoordination and recumbency. Gross lesions consisted of pale areas in the skeletal muscles. The histopathological findings showed severe necrotic degenerative myopathy in association with infiltration of neutrophils and macrophages. One rabbit exhibited similar alterations in the myocardium. Mineralization was observed in the affected skeletal muscles in some cases. In order to verify if the poisoning was due to salinomycin, 20 rabbits were divided into five groups and a ration containing the drug at doses of 10, 25, 50, 75 and 100ppm was given. The administration of doses higher than 50ppm resulted in manifestation of the clinical signs seen in the outbreak of poisoning. It was concluded, that probably an error related to the mixture of salinomycin in the feed was the cause of deaths in the spontaneous outbreak of poisoning on the rabbit farm.Relata-se, pela primeira vez, um surto de intoxicação por salinomicina em coelhos. De 2000 animais, no mínimo 27 morreram após troca do coccidiostático sulfaquinoxalina pela salinomicina. A análise de parte da ração detectou 26,9ppm de salinomicina. Os sinais clínicos observados foram anorexia, apatia e lentidão com evolução para incoordenação dos movimentos e decúbito. As lesões macroscópicas consistiram de áreas pálidas na musculatura esquelética. O exame histopatológico evidenciou miopatia degenerativo-necrótica. Adicionalmente, verificou-se reação inflamatória constituída por neutrófilos e macrófagos. Um coelho apresentou lesões similares no miocárdio. Em alguns casos, mineralização estava presente nos músculos esqueléticos afetados. Vinte coelhos experimentais foram divididos em 5 grupos que receberam 10, 25, 50, 75 e 100ppm de salinomicina por via oral, com a finalidade de reproduzir a intoxicação. Os animais que receberam a partir de 50ppm de salinomicina apresentaram sinais clínicos semelhantes aos observados no surto espontâneo. Nossos resultados indicam que, provavelmente, erro na mistura da substância à ração causou a morte dos coelhos.

The rosuvastatin inducing rhabdomyolysis in McArdle disease (MD) has not been reported to date. A 35-years-old man had exercise intolerance, muscular fatigue and cramps during physical activity since infancy. He presented severe rhabdomyolysis episode with seizure and coma after use of rosuvastatin. The investigation showed increased serum creatinekinase levels and the forearm ischemic exercise did not increased venous lactate. The muscle biopsy showed subsarcolemmal and central acummulation of glycogen and absence of the myophosphorylase enzyme. The statin induced myopathy is discussed and the danger of its use in MD is emphasized.Rosuvastatina induzindo rabdomiólise na doença de McArdle (MD) não foi relatada até o momento. Descrevemos o caso de um homem de 35 anos que desde a infância apresentava sintomas de intolerância aos exercícios, fadiga muscular e cãibras durante o esforço físico, porém após o uso de rosuvastatina apresentou episódio de rabdomiólise com crises convulsivas e coma. A investigação mostrou creatinoquinase sérica elevada e teste do esforço isquêmico sem aumento no lactato venoso. A biópsia muscular revelou acúmulo central e subsarcolemal de glicogênio nas fibras e ausência da enzima miofosforilase. Discutimos as estatinas induzindo miopatia, enfatizando o risco do seu uso na MD.

Several drugs and toxic substances can cause muscular abnormalities and are frequent causes of acquired myopathies. We present a series of 32 patients, predominance of young adult patients, diagnosed with toxic myopathy. The most common substances inducing myopathy were corticosteroids (56.2%) followed by the propoxyphene, neuroleptics, zidovudine and drug-induced hypokalemia. The investigation showed normal serum creatine kinase levels in 65.4%, myopathic pattern of the needle electromyography in 40% and the more frequent histological diagnosis of the muscle biopsy was type 2 fiber atrophy (59.3%). Clinical features, etiology, course of the disease, serum levels of muscular enzymes, electromyographic features and, especially, muscle biopsy features are discussed.Diversos medicamentos e substâncias tóxicas podem causar alterações musculares e são causas freqüentes de miopatia adquirida. Apresentamos uma série de 32 pacientes, predomínio de pacientes adulto jovens, com miopatia tóxica. As substâncias mais relacionadas com a miopatia foram os corticosteróides (56,2%) seguidos pelo propoxifeno, neurolépticos, zidovudina e drogas indutoras de hipocalemia. A investigação mostrou níveis normais de creatino quinase sérica em 65,4%, eletromiografia de agulha com padrão miopático em 40% e o mais freqüente diagnóstico histológico da biópsia muscular foi atrofia de fibras do tipo 2 (59,3%). As manifestações clínicas, etiologia, tempo de evolução, nível sérico das enzimas musculares, alterações da eletroneuromiografia e, especialmente, da biópsia muscular são discutidos.

Um surto de intoxicação espontânea por antibióticos ionóforos em ovinos da região Central do Rio Grande do Sul é descrito. Os 16 ovinos afetados estavam em campo nativo e ingeriram acidentalmente um aditivo alimentar para frangos contendo 250g/kg de narasina. Os sinais clínicos consistiam de fraqueza, incoordenação, dispnéia, secreção nasal, decúbito e morte em poucas horas. Um ovino apresentou urina escura. Macroscopicamente havia ascite, hidrotórax, edema pulmonar e palidez hepática. Discreto grau de degeneração muscular na musculatura esquelética dos membros pélvicos e torácicos foi observado histologicamente. O diagnóstico de intoxicação por narasina foi realizado com base no histórico (ingestão de aditivo alimentar contendo narasina) e nos achados clinico-patológicos.An outbreak of spontaneous ionophore toxicity in sheep grazing in native pasture in Rio Grande do Sul state, Brazil is described. Sixteen sheep which had accidental access to a chicken feed additive containing 250g/kg of narasin were affected. Clinical signs consisted of weakness, incoordination, dyspnea, nasal discharge, recumbency, and death in a few hours. One sheep showed dark red urine. Grossly there were ascites, hydrothorax, pulmonary edema, and hepatic paleness. Discrete skeletal muscle degeneration was observed histologically in the muscles of the pelvic and thoracic limbs. The diagnostic of narasin toxicosis was based on history (ingestion of feed additive containing narasin), clinical, and pathological findings.

Résumé: La définition de myopathie nécrosante (MN) est histologique montrant des lésions de nécrose-régénération associées à peu ou pas d’infiltrat inflammatoire. Les causes de MN sont variées, pouvant se rencontrer aussi bien dans des affections musculaires acquises que dans certaines dystrophies musculaires de formule histologique inhabituelle. Parmi les formes acquises, les myopathies nécrosantes auto-immunes (MNAI) constituent une entité récemment individualisée au sein des myopathies dites inflammatoires (MI). Elles présentent une grande hétérogénéité sur le plan clinique, sérologique et évolutif. Initialement, elles étaient considérées comme des myopathies sévères, de début subaigu, associées à une hyperCKémie supérieure à 10 fois la normale. Cependant, des formes plus insidieuses ont été rapportées. Plusieurs tableaux clinico-sérologiques de MNAI sont distingués : les MNAI associées aux auto-anticorps anti-SRP, les MNAI associées aux anticorps anti-HMG-CoA réductase, les MNAI associées à des maladies de système et les MNAI paranéoplasiques. Pour porter le diagnostic de MNAI, il est nécessaire d’exclure les diagnostics différentiels que sont les MN toxiques, certaines affections musculaires héréditaires et les autres myopathies inflammatoires pour lesquelles l’histologie peut être trompeuse. Actuellement, les MNAI sont rares mais probablement sous-diagnostiquées. L’enjeu d’un diagnostic précoce est majeur. Bien que ces formes soient fréquemment cortico-résistantes, le recours à plusieurs thérapeutiques peut permettre une bonne réponse thérapeutique. Le développement de nouvelles classifications des MI prenant en compte à la fois les critères clinico-sérologiques et anatomopathologiques devrait permettre d’améliorer leur diagnostic. Nous proposons à la fin de cette revue un arbre décisionnel diagnostique des MNAI en fonction du mode évolutif. [Copyright &y& Elsevier]

Although muscle diseases are relatively rare, several treatable myopathies must be recognized by the clinician to maximize the possibility of restoring strength in affected patients. The inflammatory myopathies, including polymyositis, dermatomyositis, inflammatory necrotizing myopathy, and myositis in association with mixed connective tissue disease, typically respond well to immunosuppressive treatment. Inclusion body myositis, a myopathy that has features of both inflammation and primary degeneration, may not be treatable at this time, but treatments are actively being sought. Muscle dysfunction caused by toxins must also be recognized because removal of the offending toxin usually results in restoration of normal muscle function. Important muscle toxins include cholesterol-lowering medications, colchicine, zidovudine, corticosteroids, emetine, and ethanol. [ABSTRACT FROM AUTHOR]

Abstract: Capecitabine plus oxaliplatin combination (XELOX) is the first-line treatment in metastatic colorectal cancer. Here we report a case of acute, severe but substantially reversible, neuromuscular and cardiac toxicity following XELOX chemotherapy. Muscle biopsy findings were consistent with a toxic myopathy with necrotizing features and vacuolar changes; COX-negative fibers were also present. The time course could support a main role for capecitabine, which may have some neurotoxic effects (more frequently central), but a detrimental interaction between the two drugs cannot be ruled out and further studies are needed. [Copyright &y& Elsevier]

Many drugs used for therapeutic interventions can cause unanticipated toxicity in muscle tissue, often leading to considerable morbidity. A drug-induced, or toxic, myopathy is defined as the acute or subacute manifestation of myopathic symptoms such as muscle weakness, myalgia, creatine kinase elevation, or myoglobinuria that can occur in patients without muscle disease when they are exposed to certain drugs. A brief review of agents with a known association with myotoxicity and the proposed mechanisms linked to that toxicity is outlined; however, the purpose of this review is to highlight recent discoveries and advances in the field of toxic myopathies that have practical implications for practicing physicians. Because many drug-related myopathies are potentially reversible at early stages, it is important for clinicians to recognize toxic myopathies early in their course to determine when to discontinue therapy and potentially prevent irreversible muscle damage. [ABSTRACT FROM AUTHOR]

The article offers information on a study which described an outbreak of salinomycin poisoning in rabbits.

Copyright of Arquivos de Neuro-Psiquiatria is the property of Thieme Medical Publishing Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Arquivos de Neuro-Psiquiatria is the property of Thieme Medical Publishing Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Der Internist is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ranolazine is a medication indicated for treatment of chronic angina and is a partial inhibitor of the fatty acid β-oxidation. We present an adult patient who developed subacute progressive muscle weakness and exercise-induced myalgia, soon after increasing the daily dose of ranolazine, in the setting of therapy with simvastatin. CK persisted normal throughout the duration of the weakness and muscle biopsy showed a lipid storage myopathy for which no underlying genetic defect was identified. Discontinuation of both drugs resulted in clinical improvement. Although simvastatin may have contributed to the myopathy, the temporal relation between the increase in ranolazine dose and the onset of the weakness would favor ranolazine as major culprit for the weakness. [ABSTRACT FROM AUTHOR]

Healthy muscle relies on a complex and interdependent network that includes, but is not limited to, proteins, ion channels, and the production and utilization of ATP. Disruptions to the system can occur for a number of reasons (genetic mutations, toxins, systemic disease, inflammation), yet they clinically present with symptoms that are nonspecific and common to myopathies: weakness, muscle pain, cramping, hypotonia. This article uses a case-based format to review the clinical reasoning and diagnostic tools that guide the accurate diagnosis of myopathies. We specifically focus on toxic, metabolic, mitochondrial, and late-onset congenital myopathies., Competing Interests: Disclosure The authors have nothing to disclose., (Copyright © 2020 Elsevier Inc. All rights reserved.)