Chloroquine myopathy

Chloroquine: Rapidly withdrawing from first-line treatment of COVID-19

The COVID-19 outbreak has garnered significant global attention due to its impact on human health. Despite its relatively low fatality rate, the virus affects multiple organ systems, resulting in various symptoms such as palpitations, headaches, muscle pain, and hearing loss among COVID-19 patients and those recovering from the disease. These symptoms impose a substantial physical, psychological, and social burden on affected individuals. On February 15, 2020, the Chinese government advised incorporating antimalarial drugs into the guidelines issued by the National Health Commission of China for preventing, diagnosing, and treating COVID-19 pneumonia. We examine the adverse effects of Chloroquine (CQ) in treating COVID-19 complications to understand why it is no longer the primary treatment for the disease.

Skeletal Muscle Manifestations and Creatine Kinase in COVID-19

Background and Purpose

Skeletal muscle symptoms and elevated creatine kinase (CK) levels have been consistently reported as part of the COVID-19 disease process. Previous studies have yet to show a consistent relationship between CK levels and skeletal muscle symptoms, disease severity, and death from COVID-19. The purpose of this study is to determine whether elevated CK is associated with a COVID-19 course requiring intubation, intensive care, and/or causing death. Secondary objectives: To determine if there is a relationship between elevated CK and (1) skeletal muscle symptoms/signs (2) complications of COVID-19 and (3) other diagnostic laboratory values.

Methods

This is a retrospective, single center cohort study. Data were collected from March 13, 2020, to May 13, 2020. This study included 289 hospitalized patients with laboratory-confirmed SARS-CoV-2 and measured CK levels during admission.

Results

Of 289 patients (mean age 68.5 [SD 13.8] years, 145 [50.2%] were men, 262 [90.7%] were African American) with COVID-19, 52 (18.0%) reported myalgia, 92 (31.8%) reported subjective weakness, and 132 (45.7%) had elevated CK levels (defined as greater than 220 U/L). Elevated CK was found to be associated with severity of disease, even when adjusting for inflammatory marker C-reactive protein (initial CK: OR 1.006 [95% CI: 1.002-1.011]; peak CK: OR 1.006 [95% CI: 1.002-1.01]; last CK: 1.009 [95% CI: 1.002-1.016]; q = .04). Creatine kinase was not found to be associated with skeletal muscle symptoms/signs or with other laboratory markers.

Conclusions

Creatine kinase is of possible clinical significance and may be used as an additional data point in predicting the trajectory of the COVID-19 disease process.

Chloroquine- and Hydroxychloroquine-Induced Cardiomyopathy: A Case Report and Brief Literature Review

OBJECTIVES

To present an index case and review the histologic and electron microscopic findings in chloroquine (CQ) and hydroxychloroquine (HCQ) myopathy, focusing primarily on cardiomyopathy. CQ and HCQ are antimalarial drugs with disease-modifying activity in rheumatic diseases (DMARD) and now are among the most widely used DMARDs. Although they are rare, severe adverse effects caused mainly by deposition of intracellular metabolites in both cardiac and skeletal muscle have been described. Currently, both CQ and HCQ have been proposed to have efficacy for patients with coronavirus disease 2019, and several large centers in the United States and other countries have started clinical trials.

METHODS

A case of HCQ cardiotoxicity diagnosed on an endomyocardial biopsy is presented. A review of the pathology archives was performed to identify additional cases of CQ or HCQ myopathy, and histologic changes were recorded. A brief literature review with an emphasis on pathologic findings in myopathies was performed.

RESULTS

Including the index case, 4 cases of CQ or HCQ myopathy were identified. Light microscopic findings included vacuolated myopathy, and electron microscopic findings included myeloid bodies and curvilinear inclusion bodies.

CONCLUSION

CQ and HCQ myopathy can present following long-term administration of the drug. The pathologic findings are nonspecific and overlap with other vacuolated myopathies, necessitating careful correlation of the histologic changes with the patient's medical history.

Side Effects of Chloroquine and Hydroxychloroquine on Skeletal Muscle: a Narrative Review

Purpose of Review

Concerning adverse neuromuscular effects, there are quite a few reports about the incidence and prevalence of chloroquine (CQ) and hydroxychloroquine (HCQ) myopathy. Given the above, I decided to explore the relationships of these drugs with skeletal muscle in an attempt to clarify how they affect the muscle now and in the future, as millions of people are using CQ and HCQ.

Recent Findings

The literature review identified 28 publications about CQ/HCQ myopathy, totaling 56 patients, from 1963 to 2020. A compilation of all patients was carried out by computing demographic features, clinical aspects, laboratory exams, and clinical evolution. All articles but two represented a large series about incidence and prevalence of the myopathy. Fifty-nine percent used QC, mean daily dose was 393 mg per day, and mean duration of treatment was 37 months. The predominant underlying diseases were rheumatoid arthritis (42.8%) and lupus erythematosus (26.8%). Respiratory distress was present in 12.5% in patients with proximal muscle weakness (87.2%). Dysphagia and cervical and axial weakness were observed in a smaller percentage. Creatine kinase was elevated in 60.7%, and EMG showed a myopathic pattern in 54%. Muscle biopsy showed a vacuolar pattern in 53.7%, and curvilinear bodies (CB) were the predominant ultrastructural finding (86.8%). After drug withdrawal, 85.4% of patients improved, and 12.7% died from other causes than myopathy.

Summary

CQ and HCQ myopathy has been known for a long time, but the incidence is low, being described only with long-term use. The use of these drugs for a short period has not been reported, although a prolonged elimination half-life of these drugs actually exists.

COVID-19 and neuromuscular disorders

The coronavirus 2019 (COVID-19) pandemic has potential to disproportionately and severely affect patients with neuromuscular disorders. In a short period of time, it has already caused reorganization of neuromuscular clinical care delivery and education, which will likely have lasting effects on the field. This article reviews (1) potential neuromuscular complications of COVID-19, (2) assessment and mitigation of COVID-19-related risk for patients with preexisting neuromuscular disease, (3) guidance for management of immunosuppressive and immunomodulatory therapies, (4) practical guidance regarding neuromuscular care delivery, telemedicine, and education, and (5) effect on neuromuscular research. We outline key unanswered clinical questions and highlight the need for team-based and interspecialty collaboration. Primary goals of clinical research during this time are to develop evidence-based best practices and to minimize morbidity and mortality related to COVID-19 for patients with neuromuscular disorders.

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.

Pros and cons of different ways to address dysfunctional autophagy in Pompe disease

Autophagy is a major intracellular self-digestion process that brings cytoplasmic materials to the lysosome for degradation. Defective autophagy has been linked to a broad range of human disorders, including cancer, diabetes, neurodegeneration, autoimmunity, cardiovascular diseases, and myopathies. In Pompe disease, a severe neuromuscular disorder, disturbances in autophagic process manifest themselves as progressive accumulation of undegraded cellular debris in the diseased muscle cells. A growing body of evidence has connected this defect to the decline in muscle function and muscle resistance to the currently available treatment-enzyme replacement therapy (ERT). Both induction and inhibition of autophagy have been tested in pre-clinical studies in a mouse model of the disease. Here, we discuss strengths and weaknesses of different approaches to address autophagic dysfunction in the context of Pompe disease.

Hydroxychloroquine-induced autophagic vacuolar myopathy with mitochondrial abnormalities

Hydroxychloroquine (HCQ) and chloroquine are used worldwide for malaria as well as connective and rheumatological disorders. They have been reported to be linked to myopathy in patients. We report four patients who were receiving HCQ as part of treatment for connective tissue disorder and who presented with myopathy. The muscle biopsy in these patients was consistent with findings of HCQ toxicity. HCQ muscle toxicity is usually self-limiting after discontinuation of the drug. It also usually tends to be under-reported due to presence of various confounding factors. This warrants close monitoring and consideration of muscle biopsy as part of initial work up of patients who present with myopathy while receiving HCQ.

Role of autophagy in glycogen breakdown and its relevance to chloroquine myopathy

Several myopathies are associated with defects in autophagic and lysosomal degradation of glycogen, but it remains unclear how glycogen is targeted to the lysosome and what significance this process has for muscle cells. We have established a Drosophila melanogaster model to study glycogen autophagy in skeletal muscles, using chloroquine (CQ) to simulate a vacuolar myopathy that is completely dependent on the core autophagy genes. We show that autophagy is required for the most efficient degradation of glycogen in response to starvation. Furthermore, we show that CQ-induced myopathy can be improved by reduction of either autophagy or glycogen synthesis, the latter possibly due to a direct role of Glycogen Synthase in regulating autophagy through its interaction with Atg8.

A case of chloroquine-induced cardiomyopathy that presented as sick sinus syndrome

A 52-year-old woman with rheumatoid arthritis who had been treated with prednisone and hydroxychloroquine for >12 years presented with chest discomfort and a seizure. She was diagnosed with restrictive cardiomyopathy combined with sick sinus syndrome. A myocardial muscle biopsy was performed to identify the underlying cardiomyopathy, which showed marked muscle fiber hypertrophy, fiber dropout, slightly increased interstitial fibrous connective tissue, and extensive cytoplasmic vacuolization of the myocytes under light microscopy. Electron microscopy of the myocytes demonstrated dense, myeloid, and curvilinear bodies. The diagnosis of hydroxychloroquine-induced cardiomyopathy was made based on the clinical, hemodynamic, and pathologic findings. This is the first case report describing chloroquine-induced cardiomyopathy involving the heart conduction system.

Cardiomyopathy after chloroquine treatment

A case of cardiomyopathy combined with vacuolar myopathy in the extremity muscles and irreversible retinopathy produced by chloroquine is described.

Toxic Myopathies

Muscle tissue is highly sensitive to drugs and toxins because ot its high metabolic activity and potential sites for disruption of energy-producing pathways. Early recognition of toxic myopathies is important, as they potentially are reversible on removal of the offending toxin, with greater likelihood of complete resolution the sooner this is achieved. Clinical features range from mild muscle pain and cramps to severe weakness with rhabdomyolysis, renal failure, and even death. The pathogenic bases can be multifactorial. This article reviews drugs responsible for common types of toxic myopathy and their clinical and histopathologic features and illustrates possible underlying cellular mechanisms.

Localization of anti-clathrin antibody in the sarcomere and sensitivity of myofibril structure to chloroquine suggest a role for clathrin in myofibril assembly

Immunofluorescence microscopy has been used to demonstrate that X22, a monoclonal antibody specific for clathrin heavy chain, localizes in repetitive bands that appear soon after the fusion of skeletal myoblasts into multinucleate fibers. This organization has been found in cultures containing myotubes that develop in vitro from explants of newborn rat hindlimb cells and in myotubes derived from the L8E63 myogenic line. Bands were also prominent in skinned fibers prepared from adult rat soleus muscle and in cardiac myocytes grown in vitro from 4-day heart ventricles. Immunofluorescence banding was localized in the sarcomere as a doublet, with one element on either side of the Z line. Evidence that supports the conclusion that the reaction with X22 antibody is specific and indicative of the localization of clathrin in the sarcomere includes: (1) Identical titration of X22 antibody reactivity with the determinant in coated vesicles and in the sarcomere. (2) Conditions (eg., pH and Tris) that disrupt clathrin baskets or prevent its assembly likewise disrupt the localization of X22 in bands. (3) Chloroquine inhibits both the normal trafficking of clathrin in the cell and X22 banding in the sarcomere. (4) Immunoblot analysis of myotube lysates reveals a single band with an electrophoretic mobility identical to the 180,000-Da clathrin heavy chain. (5) The assembly of clathrin into sarcomeric bands occurs early in the development of the myofibrillar apparatus. Quantitation of the appearance of X22 banding in primary cultures of myotubes indicates that it precedes that of other myofibrillar proteins and that assembly takes place in the following order: X22, titin, myosin heavy chain, actin, and desmin. The assembly of myosin, titin, and actin into sarcomeric bands, as well as X22, is inhibited by chloroquine. Upon prolonged exposure to chloroquine previously assembled proteins are drastically reduced or no longer evident in the sarcomere. On the basis of these results and considering the role of clathrin in intracellular transport and its capacity to interact with actin and alpha-actinin, we suggest that clathrin may have diverse roles in the assembly, integrity, and functioning of the sarcomere and its integration with the sarcolemma. The early organization of X22 into bands further suggests that clathrin may also function early in the assembly of the contractile system.

Therapeutic exercise for rheumatoid arthritis and osteoarthritis

Therapeutic exercise in rheumatoid arthritis and osteoarthritis may be useful in improving aerobic capacity, strengthening muscles, improving endurance and increasing flexibility. This article reviews the major studies of exercise in these conditions and summarizes the authors recommendations regarding the use of therapeutic exercise in the treatment of rheumatoid arthritis osteoarthritis.

Chloroquine neuromyotoxicity. Clinical and pathologic perspective

Six cases of toxic myopathy and/or neuropathy with chloroquine and/or hydroxychloroquine therapy are described. Two patients had unique clinical and pathologic evidence of cardiomyopathy secondary to chloroquine or hydroxychloroquine therapy. One patient had polyneuropathy secondary to chloroquine toxicity. This may be the first documentation of several features of chloroquine/hydroxychloroquine toxicity: morphologic changes in human peripheral nerve in chloroquine toxicity; chloroquine/hydroxychloroquine cardiomyopathy diagnosed by endomyocardial biopsy; and hydroxychloroquine myotoxicity. Chloroquine is a neuromyotoxin that affects nerves and cardiac and skeletal muscles. Discontinuation of chloroquine and hydroxychloroquine resulted in marked improvement in most cases. The reversibility of the symptoms emphasizes the importance of recognizing potential signs of nerve, muscle, and cardiac toxicity in patients being treated with chloroquine or hydroxychloroquine.

Ultrastructural alterations in skeletal muscle of pigs with acute monensin myotoxicosis

Large doses of monensin, a Na+-selective carboxylic ionophore, produce polyfocal, monophasic necrosis of skeletal muscle, with Type I fiber selectivity, in swine. For a study of the sequential ultrastructural alterations in affected skeletal muscles, 14 weanling pigs were given 40 mg monensin/kg body weight and were euthanatized 1, 2, 4, 8, and 16 days later. Myotoxicosis and myoglobinuria were apparent clinically. At necropsy, white, dry areas of necrosis were present in the muscle masses of the anterior and posterior thigh, shoulder, and loin. Two patterns of skeletal muscle necrosis were observed on Day 1, especially in Type I fibers. In fibers exhibiting the first of these patterns, the contractile material was disrupted, forming dense amorphous and filamentous clumps scattered within the persistent sheaths of external lamina (sarcolemmal tubes); the mitochondria were swollen and contained flocculent matrix densities, and the nuclei were pyknotic. Fibers showing the second pattern were uniformly dense, but their sarcoplasm was not disrupted. Sublethally injured fibers were also observed and showed focal myofibrillar lysis. On Days 2 and 4, the necrotic muscle had marked infiltration of macrophages in the interstitium and within sarcolemmal tubes. Rapid resolution of the fiber necrosis occurred by phagocytosis of the sarcoplasmic debris. Regeneration of affected muscles developed early following injury and progressed rapidly to complete restoration of the necrotic muscles without residual fibrosis. Regeneration was initiated on Day 1 by activation of satellite cells to form presumptive myoblasts; on Days 4 and 8 these cells showed evidence of fusion, forming myotubes to restore the necrotic fibers.

Adverse effects of drugs on muscle

A variety of drugs used in clinical practice may cause myopathy or interfere with neuromuscular transmission. The precise incidence of such disorders is not known, but it is almost certainly higher than is generally suspected. An important aspect of drug-induced muscular disorders is their reversibility if the offending agent is withdrawn, whereas failure to do so may lead to unnecessary morbidity. The study of drug effects on muscle provides a means of investigating the pathological reactions of muscle, and of producing experimental models of naturally occurring myopathies. Drug-induced myopathies may result from a direct toxic effect, which may be local when the drug is injected into a muscle or more diffuse when the drug is taken systemically, or may be secondary to electrolyte disturbances, muscle compression, ischaemia, neural activation or to the development of an immunological reaction directed against muscle. Repeated injections of antibiotics or drugs of addiction may lead to severe muscle fibrosis and contractures. A variety of drugs may cause an acute or subacute painful necrotising myopathy which may be associated with myoglobinuria, at times leading to acute renal failure. Clofibrate and epsilon aminocaproic acid are the drugs most frequently implicated, but a similar syndrome may occur in alcoholics and heroin addicts. Certain hypocholesterolaemic agents may induce myotonia by altering the sterol composition of the muscle cell membrane, while certain drugs including beta-adrenergic blockers and agonists, succinylcholine and diuretics may exacerbate or unmask pre-existing myotonia. In the syndrome of malignant hyperpyrexia, halothane, succinylcholine and various other agents may induce a potentially fatal state of muscular rigidity and hypermetabolism in susceptible individuals as a result of a defect in the calcium transport function of the sarcoplasmic reticulum and possibly of other cellular membranes. In corticosteroid myopathy, which is the most common form of drug-induced myopathy, there is selective atrophy of type 2 muscle fibres and the primary metabolic effect is an inhibition of RNA and protein synthesis, although protein degradation is also increased. Chloroquine and a number of related drugs with amphiphilic cationic properties may induce lysosomal storage myopathy, which may be associated with cardiomyopathy and with a more widespread form of lipidosis.

Antimalarials

The antimalarials, chloroquine, hydroxychloroquine, and quinacrine, are used primarily for malaria; but they can be beneficial for cutaneous lupus erythematosus (LE), polymorphous light eruption, solar urticaria, and porphyria cutanea tarda. Antimalarials bind to deoxyribonucleic acid (DNA) which prevents DNA and ribonucleic acid (RNA) polymerase reactions and DNA heat inactivation; and they inhibit the LE cell phenomenon, antinuclear antibody reactions, and suppress lymphocyte transformation. By competing with calcium ion, they stabilize membranes and have an anesthetic effect. Their anti-inflammatory potential is due to their inhibition of hydrolytic enzymes, stabilization of lysosomes, interference with prostaglandin synthesis, blocking of chemotaxis, and antagonism of histamine responses. The antimalarials have no sunscreening properties. The most common toxic effects are cutaneous pigmentation, nausea, vomiting, diarrhea, mild ileus, and cycloplegia. There has been a reluctance to use chloroquine and hydroxychloroquine because of the possibility of retinopathy. However, if the "safe" daily dose limit of chloroquine, 2 mg per pound of body weight, and of hydroxychloroquine, 3.5 mg per pound of body weight, is followed, the chance of retinopathy is slight. Quinacrine does not cause retinopathy, but it has more cutaneous side effects than the other two agents.

Chloroquine-induced accumulation of gangliosides and phospholipids in skeletal muscles. Quantitative determination and characterization of stored lipids

High doses of the lysosomotropic drug chloroquine result in lipid storage in many organs in animals. We used miniature pigs, type Göttingen, to study the lipid accumulation in skeletal muscle after chloroquine intoxication for more than 200 days. The lipids of the quadriceps muscle in intoxicated and in age-matched control pigs were characterized and determined. The lipid storage was larger in skeletal muscle than in any other organ of the intoxicated pigs. The concentration of phospholipids was increased threefold, acidic phospholipids relatively more than neutral ones. The lysosome-specific acidic phospholipid bis(monoacylglyceryl)phosphate content was almost 50-fold larger in the intoxicated pigs than in the controls. Cholesterol was increased slightly more than the phospholipids, but there was no particular accumulation of cholesteryl esters, which has been shown to occur in the liver. For the first time a storage of gangliosides, relatively more pronounced than of other lipids, was demonstrated in skeletal muscle in the drug-induced lipidosis. The concentration of total gangliosides was increased 10--15-fold, and the pattern of gangliosides showed some distinct changes resulting in at least a 100-fold increase in the concentration of ganglioside GM2 (II3NeuAc-GgOse4Cer).

Vacuolar myopathy associated with chloroquine, lupus erythematosus and thymoma. Report of a case with unusual mitochondrial changes and lipid accumulation in muscle

Pathological and biochemical observations are presented in a 55-year-old woman with lupus erythematosus and thymoma who developed a vacuolar myopathy while being treated with chloroquine. Electromyography showed prominent spontaneous muscle activity including myotonic discharges. Vacuoles were present in all fibre types but, in contrast to previous cases of chloroquine myopathy, were most prominent in intermediate fibres. Electron microscopy showed cytoplasmic sequestration by membranes in proximity to the t-system, many autophagic vacuoles, tubular networks, and a variety of membranous bodies, some identical to those found in certain forms of cerebral lipidosis. Other features not previously described in chloroquine myopathy included prominent mitochondrial vacuolation and sequestration of glycogen within mitochondria. Thin-layer chromatography of muscle homogenates showed an increase in all major neutral and phospholipid fractions.

Muscular dystrophy in mice after chronic subcutaneous treatment with cannabinoids

Swiss male albino mice were treated subcutaneously with the main cannabinoids (CBN, CBD, delta9-THC) at the dosage of 1 mg/kg per day for 30 days, and with the crude resin. At the end of the treatment, after supramaximal stimulation of the sciatic nerve, a significant decrease of both maximal twitch and tetanus tensions was observed in delta9-THC-treated animals; CBD and resin treatment produced some decrease in active tension, while CBN treatment induced an enhancement of the contractile strength. Histology showed lesions interpretable as due to muscular dystrophy. Analysis of protein and hydroxyproline muscular content showed a marked reduction in protein in all treated animals, with a corresponding high increase in hydroxyproline content.

Chloroquine, quinine, procaine, quinidine, tricyclic antidepressants, and methylxanthines as prostaglandin agonists and antagonists

Chloroquine, quanine, procaine, quinidine, clomipramine, theophylline, and caffeine have been shown to be strong prostaglandin antagonists and weak agonists. The antagonist effect is clearly demonstrable at concentrations reached in human plasma when the drugs are used therapeutically. This suggests that prostaglandins are important in several situations in which their role has hitherto been unsuspected. New approaches to the development of prostaglandin antagonists and new uses for established drugs are indicated. In a preliminary study chloroquine has been successfully used to close patent ductus arteriosus in three infants.

Study of chloroquine toxicity and a drug-induced cerebrospinal lipodystrophy in swine

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