Incidence of myopathy in patients treated with antimalarials. A report of three cases and a review of the literature

Safety monitoring of drug-induced muscle injury and rhabdomyolysis: a biomarker-guided approach for clinical practice and drug trials

Skeletal muscle tissue (SKM) may be damaged due to mechanical, metabolic, and exertional causes. However, drug-induced myopathy is among the most frequent causes of muscle disease. The clinical picture of drug-induced myopathies may be highly variable. It may present as asymptomatic or mild myalgias, with or without muscle weakness, which are likely underreported. However, it may also appear as chronic myopathy with severe weakness and, rarely, even as massive rhabdomyolysis with acute kidney injury (AKI). Unfortunately, the available biomarkers for SKM injury do not fully meet the needs for satisfactory detection of drug-induced damage, both in clinical and research settings, mainly due to their low sensitivity and specificity. Therefore, the present study proposes a strategy for drug safety monitoring using the available biomarkers of SKM injury. Moreover, we will discuss mechanisms of drug-induced SKM injury, traditional laboratory testing for SKM injury, and novel skeletal myocyte biomarkers under investigation. This can be incredibly useful in both clinical practice and for de-challenge/re-challenge investigational trials where the risk of drug-induced SKM injury is present.

Hydroxychloroquine and Fabry Disease: Three Case Reports Examining an Unexpected Pathologic Link and a Review of the Literature

Background

Hydroxychloroquine is an effective and widely used treatment in multiple autoimmune connective tissue diseases that gained a lot of publicity in the coronavirus disease 2019 (COVID-19) pandemic. Our case reports are unique in that they explore the rare and sometimes overlooked effects of this drug on multiple organ systems, specifically the kidney, cardiac muscle, and skeletal muscle. We include key histologic features in images which aid in identifying and distinguishing hydroxychloroquine toxicity from mimickers. Lastly, we report the very interesting similarity in the intracellular action of hydroxychloroquine to the pathology of Fabry disease (and its associated lysosomal enzyme, α-galactosidase A). Case Presentation. We will examine the case presentations of three female Caucasian patients: a 22-year-old with lupus nephritis class V, a 72-year-old with long-standing systemic lupus erythematosus, and a 74-year-old with undifferentiated connective tissue disease. All three patients were on hydroxychloroquine therapy for varying amounts of time with histologic evidence of hydroxychloroquine toxicity that is three is present in histological samples of the kidney, the heart, and the skeletal muscle.

Conclusions

Hydroxychloroquine is a very important and beneficial medication used for various autoimmune connective tissue diseases. Clinicians should be aware of the rare but sometimes serious side effects that can result from the medication, which at times can mimic manifestations of the connective tissue disease itself or Fabry disease. A thorough investigation should be performed in these cases to properly elucidate the cause followed by the appropriate targeted therapy.

Nanocarriers in the Delivery of Hydroxychloroquine to the Respiratory System: An Alternative to COVID-19

In response to the global outbreak caused by SARS-CoV-2, this article aims to propose the development of nanosystems for the delivery of hydroxychloroquine in the respiratory system to the treatment of COVID-19. A descriptive literature review was conducted, using the descriptors "COVID-19", "Nanotechnology", "Respiratory Syndrome" and "Hydroxychloroquine", in the PubMed, ScienceDirect and SciElo databases. After analyzing the articles according to the inclusion and exclusion criteria, they were divided into 3 sessions: Coronavirus: definitions, classifications and epidemiology, pharmacological aspects of hydroxychloroquine and pharmaceutical nanotechnology in targeting of drugs. We used 131 articles published until July 18, 2020. Hydroxychloroquine seems to promote a reduction in viral load, in vivo studies, preventing the entry of SARS-CoV-2 into lung cells, and the safety of its administration is questioned due to the toxic effects that it can develop, such as retinopathy, hypoglycemia and even cardiotoxicity. Nanosystems for the delivery of drugs in the respiratory system may be a viable alternative for the administration of hydroxychloroquine, which may enhance the therapeutic effect of the drug with a consequent decrease in its toxicity, providing greater safety for implementation in the clinic in the treatment of COVID-19.

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

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

Systemic toxicity of chloroquine and hydroxychloroquine: prevalence, mechanisms, risk factors, prognostic and screening possibilities

Chloroquine (CQ) and its hydroxylated analog, hydroxychloroquine (HCQ), are 4-aminoquinoline initially used as an antimalarial treatment. CQ and HCQ (4-aminoquinoline, 4-AQ) are today used in rheumatology, especially to treat rheumatoid arthritis and systemic lupus erythematosus. Their mechanism of action revolves around a singular triptych: 4-AQ acts as alkalizing agents, ionized amphiphilic molecules, and by binding to numerous targets. 4-AQ have so pleiotropic and original mechanisms of action, providing them an effect at the heart of the regulation of several physiological functions. However, this broad spectrum of action is also at the origin of various and original side effects, notably a remarkable chronic systemic toxicity. We describe here the 4-AQ-induced lesions on the eye, the heart, muscle, the nerves, the inner ear, and the kidney. We also describe their prevalence, their pathophysiological mechanisms, their risk factors, their potential severity, and the means to detect them early. Most of these side effects are reversible if treatment is stopped promptly. This 4-AQ-induced toxicity must be known to prescribing physicians, to closely monitor its appearance and stop treatment in time if necessary.

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.

Malaria-induced ptosis

Purpose

This study reports two cases of malaria-induced ptosis with surgical resolution.

Observations

Case 1 is a 27-year-old female with a past medical history of bilateral ptosis following childhood malaria. Case 2 is a 63-year-old male with left-side ptosis following adult-onset malaria. Both patients required revision surgery but ultimately did well after surgical correction.

Conclusions and importance

Malaria-induced ptosis is a rare entity that should be suspected in patients presenting with ptosis following infection and treatment of malaria. It is unknown if the patients’ malaria results from malarial infection, antimalarial treatment, or a combination of both. Surgical correction is the mainstay of treatment.

Chloroquine and Hydroxychloroquine Myopathy: Clinical Spectrum and Treatment Outcomes

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.

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.

The role of neutrophil extracellular traps and TLR signaling in skeletal muscle ischemia reperfusion injury

Ischemia reperfusion (IR) injury results in devastating skeletal muscle fibrosis. Here, we recapitulate this injury with a mouse model of hindlimb IR injury which leads to skeletal muscle fibrosis. Injury resulted in extensive immune infiltration with robust neutrophil extracellular trap (NET) formation in the skeletal muscle, however, direct targeting of NETs via the peptidylarginine deiminase 4 (PAD4) mechanism was insufficient to reduce muscle fibrosis. Circulating levels of IL-10 and TNFα were significantly elevated post injury, indicating toll-like receptor (TLR) signaling may be involved in muscle injury. Administration of hydroxychloroquine (HCQ), a small molecule inhibitor of TLR7/8/9, following injury reduced NET formation, IL-10, and TNFα levels and ultimately mitigated muscle fibrosis and improved myofiber regeneration following IR injury. HCQ treatment decreased fibroadipogenic progenitor cell proliferation and partially inhibited ERK1/2 phosphorylation in the injured tissue, suggesting it may act through a combination of TLR7/8/9 and ERK signaling mechanisms. We demonstrate that treatment with FDA-approved HCQ leads to decreased muscle fibrosis and increased myofiber regeneration following IR injury, suggesting short-term HCQ treatment may be a viable treatment to prevent muscle fibrosis in ischemia reperfusion and traumatic extremity injury.

Expanding horizons for clinical applications of chloroquine, hydroxychloroquine, and related structural analogues

Several experimental and clinical studies have transformed the traditional antimalarial role of chloroquine (CHQ) and related structural analogues to potent therapeutic agents for a host of nonmalarial indications. The expanding clinical applicability for these drugs includes rheumatological and cardiovascular disorders (CVD), chronic kidney disease (CKD), oncology, and a variety of nonmalarial infections. These clinical advancements are primarily related to pleiotropic pharmacological actions of these drugs, including immunomodulation, anti-inflammatory properties, and capabilities of inducing autophagy and apoptosis at a cellular level. Historically, many clinical benefits in nonmalarial indications were first recognized through serendipitous observations; however, with numerous ongoing systematic clinical studies, the clinical horizons of these drugs have a promising future.

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.

Autophagy Defects in Skeletal Myopathies

Autophagy is an evolutionarily conserved catabolic process that targets different types of cytoplasmic cargo (such as bulk cytoplasm, damaged cellular organelles, and misfolded protein aggregates) for lysosomal degradation. Autophagy is activated in response to biological stress and also plays a critical role in the maintenance of normal cellular homeostasis; the latter function is particularly important for the integrity of postmitotic, metabolically active tissues, such as skeletal muscle. Through impairment of muscle homeostasis, autophagy dysfunction contributes to the pathogenesis of many different skeletal myopathies; the observed autophagy defects differ from disease to disease but have been shown to involve all steps of the autophagic cascade (from induction to lysosomal cargo degradation) and to impair both bulk and selective autophagy. To highlight the molecular and cellular mechanisms that are shared among different myopathies with deficient autophagy, these disorders are discussed based on the nature of the underlying autophagic defect rather than etiology or clinical presentation.

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.

Beyond the joints: neurological involvement in rheumatoid arthritis

Although arthritis is the most notable component, rheumatoid arthritis (RA) is a systemic inflammatory disorder where extra-articular manifestations are common; among them, central and peripheral nervous system involvement is frequent and associated with significant morbidity and, in some cases, reduced life span. It may produce a myriad of symptoms and signs ranging from subtle numbness in a hand, to quadriparesis and sudden death. Central and peripheral neurologic manifestations may arise from structural damage produced by RA in diarthroidal joints, by the systemic inflammatory process of the disease itself or by the drugs used to treat it. Neurologic syndromes may appear suddenly or developed slowly through months, and emerge early or after years of having RA. Neurologic manifestations may be easily overlooked or incorrectly assigned to peripheral arthritis unless the attending physician is aware of these complications. In this article, we review neurologic involvement in RA patients with emphasis on clinical approach for early detection.

Third cranial nerve palsy or pseudo 3rd nerve palsy of myasthenia gravis? A challenging diagnosis in systemic lupus erythematosus

Diplopia is frequently encountered in neurological practice and may occur as part of the clinical spectrum of 3rd cranial nerve palsy. Correct localization of the underlying problem is the first step in making an accurate diagnosis. Pathologies affecting the supranuclear structures, cranial nerves and nuclei, extraocular muscles and the neuromuscular junction may cause or simulate 3rd nerve palsy. We report a case of a patient with longstanding quiescent SLE who presented with sudden onset of diplopia and discuss possible aetiologies including ischemia, demyelination, neuromuscular conditions and medication-induced.

Assessment of safety of the major antimalarial drugs

Antimalarial drugs remain the major intervention tool for the global malaria control efforts that save millions of lives. Nonetheless, emergence and spread of Plasmodium parasites resistant against chloroquine and other major antimalarial drugs has brought the urgency to develop a new generation of safe and effective drugs against malaria. In this article, the safety data for major antimalarial drugs is reviewed. Although an ample amount of clinical data regarding the safety and tolerability of several of these drugs in older children and adults is available, more critical safety and tolerability studies in pregnant women and young children is desirable. To offset the partial loss in efficacy due to drug resistance in malaria parasites acquired against specific drugs, treatment regimens often rely upon the combination of two or more drugs. However, combination therapy requires additional safety, toxicity and tolerability studies in all population groups where these drugs are administered. A uniform standard in assessing the safety and tolerability of antimalarial drugs will be useful in the formulation and implementation of malaria treatment policies that are based on the drug effectiveness, safety and tolerability.

Drug-Induced Musculoskeletal Disorders

Drug-induced musculoskeletal disorders represent a broad clinical spectrum, from asymptomatic biological abnormalities to severe and even life-threatening diseases. Since an increasing number of drugs have been implicated in inducing rheumatic symptoms and/or syndromes, this review is not meant to be exhaustive, bearing in mind that the development of any musculoskeletal disorder should be considered as possibly related to a medication. The purpose of this article is to provide an overview of the more frequent drug-induced musculoskeletal disorders. These include: (i) arthralgias and arthropathies, including chondropathies and inflammatory arthritis; (ii) connective tissue diseases, especially lupus-like syndromes; (iii) periarticular disorders, including tendinopathies, enthesopathies and frozen shoulder; (iii) bone diseases, such as osteoporosis, osteomalacia and osteonecrosis; and (iv) myopathies. Although virtually all drug classes may induce musculoskeletal disorders, a significant part of them are related to corticosteroids, vaccines, antibacterials and lipid-lowering agents. Knowledge of drug-induced musculoskeletal disorders avoids carrying out unnecessary investigations, and allows optimal management of the patients, i.e. early discontinuation of the offending agent, adequate treatment monitoring and/or intervention with appropriate preventive actions.

[Occurrence of chloroquine-induced myopathy after low-dose treatment of rheumatoid arthritis for seven years]

The myotoxicity of chloroquine and hydroxychloroquine has been known for decades. Limb-girdle weakness due to a vacuolar myopathy may occur occasionally in a dose-dependent manner during the first 24 months on chloroquine. However, we report on a case in which muscular weakness developed after a daily intake of 250 chloroquine phosphate (= 155 mg chloroquine base) for a period of 7 years. Even after long-term and apparently well-tolerated chloroquine treatment, the occurrence of severe side-effects is possible.

Antimalarial myopathy: an underdiagnosed complication? Prospective longitudinal study of 119 patients

OBJECTIVES

To evaluate the prevalence and incidence of antimalarial myopathy in patients with rheumatic diseases treated with antimalarial drugs.

METHODS

Over a three year period, all patients with rheumatic diseases who were taking antimalarial drugs were studied. Serum muscle enzymes were assessed at the time of inclusion and every six months thereafter. Muscle strength, electromyography (EMG), and muscle biopsy were assessed in patients with a persistent muscle enzyme disturbances.

RESULTS

119 patients were included (111 chloroquine, eight hydroxychloroquine). Of these, 22 (18.5%) had a persistent muscle enzyme disturbance: lactate dehydrogenase 19/22 (86%); creatine kinase 7/22 (32%), and aldolase 3/22 (14%). Findings of antimalarial myopathy were detected in 3/15 biopsied patients (20%) by light microscopy and in all 15 by electron microscopy. Eleven patients had myopathy at the time of inclusion (prevalence 9.2%) and four patients developed muscle injury during follow up (annual incidence 1.2%). Muscle weakness was observed in 8 of 15 patients with biopsy proven myopathy, giving a prevalence of clinical antimalarial myopathy of 6.7%. All these patients also had a myopathic pattern on electromyography.

CONCLUSIONS

The prevalence of antimalarial myopathy is higher than previously recognised when muscle enzyme determination is used as a screening method. When a persistent muscle enzyme disturbance is observed, clinical and electromyographic studies should be undertaken periodically to detect the development of clinical myopathy. In cases of clinical myopathy, an anatomical-pathological tissue study, including an ultrastructural study, is mandatory to confirm the diagnosis.

Hydroxychloroquine cardiotoxicity in systemic lupus erythematosus: a report of 2 cases and review of the literature

BACKGROUND

Hydroxychloroquine (HCQ) is extensively used in the long-term treatment of systemic lupus erythematosus (SLE). Although considered by clinicians to be relatively safe, serious side effects have been documented in the literature. Retinotoxicity has received the most attention, whereas neuromyotoxicity and cardiotoxicity have been described in isolated case reports. We present 2 cases of potential cardiotoxicity occurring in patients with SLE while receiving long-term HCQ therapy.

OBJECTIVE

To review the incidence, presentation, and mechanism of serious antimalarial toxicity, and to discuss the impact of HCQ on cardiac health in SLE.

METHODS

The authors reviewed the English-language literature from 1948 to December 2002 using Medline databases.

RESULTS

In addition to our patients, there are 2 published cases of biopsy-proven HCQ cardiotoxicity in the English-language literature. Both occurred in patients with SLE. The literature indicates that antimalarial cardiotoxicity may be of particular importance in patients with SLE given their already increased cardiac risk due to primary heart disease and accelerated atherosclerosis. Endomyocardial biopsy reveals a constellation of findings including vacuolar myopathy, myeloid bodies, and curvilinear bodies.

CONCLUSIONS

As HCQ use among SLE patients increases, clinicians should be alert to the possibility of antimalarial cardiotoxicity. The potential severity and reversibility of this complication underscore the importance of timely diagnosis. The cases presented here, one with biopsy and one without, illustrate the utility of endomyocardial biopsy in HCQ-treated SLE patients with cardiac complaints to ensure accurate diagnosis and appropriate management.

Antimalarial Drug Toxicity

Malaria, caused mostly by Plasmodium falciparum and P. vivax, remains one of the most important infectious diseases in the world. Antimalarial drug toxicity is one side of the risk-benefit equation and is viewed differently depending upon whether the clinical indication for drug administration is malaria treatment or prophylaxis. Drug toxicity must be acceptable to patients and cause less harm than the disease itself. Research that leads to drug registration tends to omit two important groups who are particularly vulnerable to malaria--very young children and pregnant women. Prescribing in pregnancy is a particular problem for clinicians because the risk-benefit ratio is often very unclear. The number of antimalarial drugs in use is very small. Despite its decreasing efficacy against P. falciparum, chloroquine continues to be used widely because of its low cost and good tolerability. It remains the drug of first choice for treating P. vivax malaria. Pruritus is a common adverse effect in African patients. As prophylaxis, chloroquine is usually combined with proguanil. This combination has good overall tolerability but mouth ulcers and gastrointestinal upset are more common than with other prophylactic regimens. Sulfadoxine/pyrimethamine is well tolerated as treatment and when used as intermittent preventive treatment in pregnant African women. Sulfadoxine/pyrimethamine is no longer used as prophylaxis because it may cause toxic epidermal necrolysis and Stevens Johnson syndrome. Mefloquine remains a valuable drug for prophylaxis and treatment. Tolerability is acceptable to most patients and travellers despite the impression given by the lay press. Dose-related serious neuropsychiatric toxicity can occur; mefloquine is contraindicated in individuals with a history of epilepsy or psychiatric disease. Quinine is the mainstay for treating severe malaria in many countries. Cardiovascular or CNS toxicity is rare, but hypoglycaemia may be problematic and blood glucose levels should be monitored. Halofantrine is unsuitable for widespread use because of its potential for cardiotoxicity. There is renewed interest in two old drugs, primaquine and amodiaquine. Primaquine is being developed as prophylaxis, and amodiaquine, which was withdrawn from prophylactic use because of neutropenia and hepatitis, is a potentially good partner drug for artesunate against falciparum malaria. Atovaquone/proguanil is a new antimalarial combination with good efficacy and tolerability as prophylaxis and treatment. The most important class of drugs that could have a major impact on malaria control is the artemisinin derivatives. They have remarkable efficacy and an excellent safety record. They have no identifiable dose-related adverse effects in humans and only very rarely produce allergic reactions. Combining an artemisinin derivative with another efficacious antimalarial drug is increasingly being viewed as the optimal therapeutic strategy for malaria.

Chloroquine-induced phospholipidosis of the kidney mimicking Fabry's disease: case report and review of the literature

A 46-year-old female patient with Sjögren's syndrome, hypertension, and stable chronic renal insufficiency (creatinine [CR], 1.9 to 2.1 mg/dL) had a progressive worsening of renal function (CR, 5.0 mg/dL) after 11 months of chloroquine therapy (155 mg/day; cumulative dose of approximately 51 g). Light microscopy revealed nonspecific angionephrosclerosis. Electron microscopy showed accumulations of lamellated myelinoid material and occasionally also of curvilinear bodies, especially in the glomerular podocytes and to a lesser extent in vascular myothelial and endothelial cells. In the tubular system, mainly protein droplets were stored. Activity of alpha-galactosidase A was normal in isolated leukocytes (56 nmol/mg; range, 33.2 to 109 nmol/mg), ruling out Fabry's disease. Clinical, morphological, and biochemical findings were consistent with chloroquine-associated deterioration of renal function that improved considerably after discontinuation of chloroquine treatment. Adverse effects of chloroquine may aggravate preexisting renal disease. Electron microscopy is a worthwhile tool for establishing the correct diagnosis.

Muscle diseases in elders: a 10-year retrospective study

BACKGROUND

Muscle complaints are frequent among older adults, but histological data in this setting are scarce. Our objective was to detect the major categories of muscle diseases in the elderly population based on histological study.

METHODS

We reviewed all muscle biopsies performed in our hospital on patients older than the age of 65 during a 10-year period (1988-1997). As a control group, we included the next patient younger than 65 who underwent muscle biopsy after each elderly patient. We recorded demographic, clinical, and histological data of the patients, as well as the final diagnosis. Concordance between pre- and postbiopsy diagnosis was also analyzed.

RESULTS

We included 239 muscle biopsies corresponding to elderly patients and 239 to controls. Compared with the control group, elderly patients more frequently exhibited type II fiber atrophy and were diagnosed with a specific myopathy. The latter was achieved in 86 cases (36%), idiopathic inflammatory myopathies and vasculitis being the most frequent diagnoses. Interestingly, in about one quarter of the elderly patients in whom a definite diagnosis of muscle disease was achieved, this diagnosis had not been clinically suspected prior to muscle biopsy. Overall, in 60 out of 239 elderly patients (25%), a specific therapeutic regimen could be instituted on the basis of the muscle biopsy results.

CONCLUSIONS

Muscle diseases are not rare in elderly patients. Therefore, muscle biopsy constitutes a safe and useful tool for diagnosis because, if not performed, some potentially treatable diseases may be undiagnosed or misdiagnosed.

Metabolic myopathies. A diagnostic evaluation

This article briefly reviews the initial approach to the patient suspected of having metabolic myopathy. Diagnostic highlights include relevant points of history, physical examination, blood work-up, forearm ischemic exercise test, electrophysiologic testings and muscle biopsy. The diagnostic evaluation is discussed in detail in separate articles.

Long-term effectiveness of antimalarial drugs in rheumatic diseases

OBJECTIVE

The purpose of this study was to compare the long-term effectiveness between chloroquine (CQ) and hydroxychloroquine (HCQ).

METHODS

Medical charts of all patients seen by eight rheumatologists practising in two tertiary care centres and starting antimalarial treatment between January 1985 and December 1993 were reviewed. Patient characteristics, disease, and treatment information were collected. The main outcome measures were the cause of and the time to the discontinuation of antimalarial drugs resulting from all causes, principally toxicity or inefficacy, or both. Bivariate analysis including t tests and chi 2 tests were used to assess differences between means and proportions respectively. Survival curves were evaluated using the Kaplan-Meier method. Multivariate analysis (Cox regression) was used to adjust for potential confounders.

RESULTS

After all medical records were reviewed, 1042 eligible cases were identified. From these, 940 (90%) had usable information and they represent the cohort. Five hundred and fifty eight had rheumatoid arthritis, 178 had systemic lupus erythematosus, 127 had palindromic arthritis, and 77 had other diagnoses. Fifty seven per cent of the patients received CQ and 43% HCQ. The proportion of patients with side effects taking HCQ and CQ was 15% and 28% respectively (p = 0.001). Using Cox regression model to adjust for age at the onset of antimalarial treatment, physician differences, sex, disease type, disease duration before treatment, and rank selection, there were no differences in the hazard ratio (HR) for overall discontinuations between CQ and HCQ. While the HR for discontinuations because of toxicity was lower for HCQ (HR = 0.6, 95% CI 0.4, 0.9), the HR for discontinuations because of inefficacy was significantly higher for HCQ (HR = 1.4, 95% CI 1.1, 1.9).

CONCLUSIONS

After adjusting for time and several confounders HCQ was less toxic but less effective than CQ. Only one case of probable/possible retinopathy was found. Therefore, we propose a careful baseline ophthalmological evaluation by an expert and then one or every two years if proper doses are used.

Muscle involvement in rheumatoid arthritis: clinicopathological study of 21 symptomatic cases

The aim of the current study was to analyze the frequency and characteristics of symptomatic myopathies occurring in rheumatoid arthritis (RA) patients, to correlate these findings with clinical data, and to evaluate their therapeutic implications. All RA patients from a cohort of 350 RA patients from a single institution who developed muscular symptomatology during an 8-year period were included in the study (n = 21). Clinical and laboratory data and electromyographic results were recorded in all cases, and an open muscle biopsy was performed. Weakness and muscle atrophy were the most common symptoms. Serum creatine kinase was increased in 8 cases (38%). Histopathologic study showed type 2 atrophy in 12 cases. In 13 cases, a treatable disease was diagnosed: dermatomyositis (n = 2), d-penicillamine-related dermatomyositis (n = 2), polymyositis (n = 1), muscular mononuclear cell infiltration (n = 3), polyarteritis nodosa (n = 1), glucocorticoid myopathy (n = 3), and toxic chloroquine myopathy (n = 1). In all but 1 patient, muscular clinical response to new therapy and/or drug withdrawal was satisfactory. Although symptomatic muscular involvement in RA is low (6% in the current series), we have found that nearly two thirds of cases were caused by potentially treatable conditions, mainly myositis or toxic myopathies.