Congenital myopathies are a heterogeneous group of rare, inherited muscle diseases that typically announce themselves in infancy or childhood through progressive muscle weakness. The genetic defects behind these conditions disrupt the fundamental machinery of the muscle fiber, affecting structures such as the contractile apparatus itself, the systems that handle calcium within muscle cells, and the mitochondria that supply the energy muscle contraction demands. The resulting weakness can compromise the ability to walk, to rise from the floor, and to use the arms and hands for everyday tasks, and in the most severe cases it extends to the respiratory muscles, threatening breathing itself. Because the underlying genetic faults cannot currently be repaired, clinical care has been confined to symptom management: physical therapy, orthopedic interventions, respiratory support, and vigilance against complications. There has been no drug that meaningfully changes what these children can do with their bodies day to day.

The new study, led by researchers at the University of Gothenburg together with clinicians at the Queen Silvia Children’s Hospital, set out to test whether salbutamol, known in some countries as albuterol, could change that picture. Salbutamol is a beta-2 adrenergic agonist, a molecule that stimulates beta-2 receptors and has been inhaled by asthma patients for decades because it rapidly relaxes the smooth muscle of the airways. But when the same compound is taken orally rather than inhaled, it reaches the bloodstream in concentrations that allow it to act on skeletal muscle as well. Beta-2 receptors on muscle fibers participate in signaling pathways that influence protein turnover, and experimental work has shown that beta-2 agonists can stimulate the synthesis of muscle protein, tilting the balance between muscle building and muscle breakdown toward growth. This anabolic side effect is precisely why the drug attracted the attention of neuromuscular researchers interested in conditions defined by weakness rather than by airway disease.

The trial, known as COMPIS, enrolled 18 individuals aged 6 to 16, every one of whom had a congenital myopathy confirmed by genetic testing. The design was a randomized, open-label, blinded-endpoint crossover study, a format well suited to rare diseases where patient numbers are inevitably small. Half the participants began with 24 weeks of oral salbutamol added to their usual care, while the other half continued with usual care alone; after that period, the groups switched. Because each child served as their own control, the comparison between treatment and no treatment could be made within the same individual, reducing the noise that genetic heterogeneity and differing disease severity would otherwise introduce. Assessors scoring the outcomes remained blinded to which treatment period the measurements came from, protecting the results from observer bias even though participants and clinicians necessarily knew what drug was being taken.

The primary outcome was motor function measured with the MFM-32, a standardized rating scale developed specifically for neuromuscular diseases that evaluates what patients can actually do, from standing and transferring to handling objects. After the salbutamol periods, motor function scores were on average 3.61 points higher than after the standard-care periods. In the world of neuromuscular medicine, where meaningful change on such scales is often measured in single digits over years, a difference of that magnitude achieved in half a year is regarded as a clear and clinically relevant improvement. Muscle strength told the same story. Grip strength in the dominant hand increased by the equivalent of roughly 1.5 kilograms during salbutamol treatment compared with standard care alone, and although increases in other tested muscle groups did not reach statistical significance, the direction of change was consistently favorable.

Perhaps the most striking results came from the functional tests performed by the eleven participants who were able to walk. In the six-minute walk test, a standard measure of endurance and mobility in neuromuscular research, the children covered an average of 435 meters before the trial. During salbutamol treatment, that distance rose to 473 meters, an additional 38 meters of walking that represents real, visible gains in stamina for children whose energy reserves are severely limited. For context, children of similar age with typical muscle function walk about 600 meters in six minutes, so the drug moved these patients meaningfully closer to normal performance. The researchers also timed how quickly the ambulatory children could rise from the floor to a standing position, a classic test of proximal muscle power. Before treatment, the task took an average of 8.29 seconds; with salbutamol, it took 6.39 seconds. A child with normal strength completes the same movement in one to two seconds, which illustrates both how impaired these children were and how much ground the medication helped them recover.

The benefits extended beyond the limbs. Forced vital capacity, the volume of air a person can exhale after taking the deepest possible breath, was on average approximately 0.2 liters higher during salbutamol treatment than during standard care. In congenital myopathies, weakening of the respiratory muscles is one of the most feared aspects of the disease, driving recurrent chest infections, sleep-disordered breathing, and eventually the need for ventilatory support. A measurable improvement in respiratory muscle performance, even a modest one, therefore carries potential importance well beyond the numbers themselves. The treatment was well tolerated throughout the study, and no serious side effects were reported, an encouraging safety profile for a drug whose tolerability in children is already extensively characterized from decades of asthma use.

For the families involved, the significance of the trial is captured less by rating scales than by daily life. Eva Michael, a doctoral student in pediatric neurology at the University of Gothenburg and a specialist physician at the Queen Silvia Children’s Hospital, described the change she observed in the children’s everyday functioning. Simply the fact that they had more energy, she noted, that they could manage a full day at school followed by activities and homework without becoming completely exhausted and bursting into tears, is very important for these children. That framing underscores a point that clinical trials in rare diseases often struggle to convey: for a child who cannot sustain a normal day, an incremental gain in endurance can translate into participation in school, friendships, and family life that would otherwise be out of reach.

The researchers themselves are careful about what the study can and cannot establish. With 18 participants at a single center in Sweden, the trial is small, and congenital myopathies encompass many distinct genetic subtypes that may respond differently to a beta-2 agonist. The open-label design, with blinded endpoint assessment, cannot fully exclude expectation effects on the part of participants and families. Michael and her colleagues emphasize that the findings need to be confirmed in larger international studies involving longer treatment periods and follow-up before any change to clinical practice. Even so, the results suggest that oral salbutamol could potentially become a symptom-relieving treatment option for children and adolescents with congenital myopathies in the future, pending the development of other drugs that might address the diseases more fundamentally.

If those larger trials succeed, the implications would extend well beyond this single rare disease community. Salbutamol is cheap, globally available, and already approved for pediatric use, meaning that a positive confirmation could translate into treatment access far faster than a newly developed molecule ever could. The trial also adds to a growing body of evidence that repurposing established drugs can open doors in neuromuscular medicine, where the small patient populations of individual genetic disorders rarely justify the cost of developing therapies from scratch. For now, the COMPIS results stand as a carefully controlled demonstration that a familiar asthma inhaler medication, taken by mouth, can give children with congenital myopathies something they have never had before: a medicine that measurably strengthens the muscles they rely on to stand, to walk, and simply to get through their day.

Subject of Research: Oral salbutamol treatment for motor function and muscle strength in children with congenital myopathies

Article Title: Asthma medication improved motor skills and strength in children with muscle disease

Article References: Asthma medication improved motor skills and strength in children with muscle disease. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: salbutamol, congenital myopathies, neuromuscular disease, randomized crossover trial, muscle strength, motor function, pediatric neurology, six-minute walk test, forced vital capacity, drug repurposing, University of Gothenburg, EClinicalMedicine

The research team, led by Ioannis Liampas of the University of Thessaly and University of Patras in Greece, systematically searched MEDLINE, Embase, CENTRAL, and Google Scholar from their inception through May 2026. Their goal was to answer a deceptively simple question: does the age at which myasthenia gravis begins change how severe it is at the start, and does it change where patients end up years later? Observational studies of adults with myasthenia gravis that compared age-at-onset groups were eligible for inclusion. After screening, ten studies made it into the review, and four of them, encompassing 647 patients with very late-onset disease and 1,620 patients with earlier-onset disease, provided enough data for the primary quantitative synthesis.

The headline result concerns what the authors defined as severe early presentation: patients classified as Myasthenia Gravis Foundation of America class IV or V at onset, at diagnosis, or at the earliest pretreatment assessment. These classes correspond to disease that has spread beyond the eye muscles to affect swallowing, speech, breathing, or the muscles of the trunk and limbs, with class V requiring intubation or mechanical ventilation. The meta-analysis found that severe early presentation occurred in 10.2 percent of patients with very late-onset disease compared with just 3.8 percent of those with earlier onset. That translates to an odds ratio of 2.19, with a 95 percent confidence interval of 1.49 to 3.24 and a p-value below 0.001, meaning the association was both statistically robust and unlikely to be a chance finding. Strikingly, the statistical heterogeneity across studies was zero, indicating remarkable consistency in the direction and magnitude of the effect.

Perhaps the most intellectually interesting part of the analysis is what happened when the researchers widened the lens. Myasthenia gravis has traditionally been split into early-onset disease, beginning before age 50, and late-onset disease, beginning at 50 or later. When the team compared the broader late-onset group against the early-onset group, the difference in severe early presentation all but vanished: 5.6 percent versus 4.2 percent, an odds ratio of 1.12 with a confidence interval spanning 0.74 to 1.71 and a p-value of 0.60. In other words, the excess risk is concentrated in the very oldest patients, and lumping everyone over 50 together masks it. This suggests that the conventional early-versus-late dichotomy is too coarse a tool for prognosis, and that the 65-year threshold captures a biologically and clinically distinct subgroup.

Beyond the numbers, the qualitative synthesis of the included studies painted a coherent picture of the very late-onset phenotype. Patients in this group more frequently showed early bulbar involvement, meaning weakness of the muscles that control chewing, swallowing, and speech, as well as early respiratory involvement, and they more often required intubation during myasthenic crises. Bulbar and respiratory weakness are the most feared manifestations of myasthenia gravis because they can rapidly compromise the airway, turning a manageable chronic condition into a medical emergency within hours. For clinicians, the message is that an older patient presenting with new-onset weakness deserves particularly close monitoring for these danger signs, even if the initial examination looks reassuring.

Yet the review’s second major conclusion cuts against therapeutic pessimism. Long-term disease-control outcomes were heterogeneous across studies, reflecting differences in how remission, minimal manifestation status, and treatment response were defined, but they were often comparable between age-at-onset groups, particularly when immunotherapy was used. In plain terms, older patients may start sicker, but with appropriate immune-directed treatment their disease can often be brought under control to a degree similar to that achieved in younger patients. The authors explicitly warn against what they call therapeutic nihilism, the mistaken assumption that aggressive treatment is futile or too risky in the elderly simply because of age.

This finding lands at a moment when the treatment landscape for myasthenia gravis is expanding rapidly. Beyond the traditional pillars of acetylcholinesterase inhibitors, corticosteroids, and conventional immunosuppressants, targeted biological therapies such as complement inhibitors and neonatal Fc receptor blockers, including efgartigimod, have entered clinical practice, and real-world studies cited in the review have examined their effectiveness specifically in very late-onset generalized disease. The availability of fast-acting agents that can rapidly reduce the levels of pathogenic autoantibodies is particularly relevant for older patients, who may be more vulnerable to the cumulative toxicities of long-term steroid use and who face higher stakes when a crisis begins.

The biology behind the age-related shift remains an open question, and the review situates its clinical findings within a growing body of immunological work. Genomic studies have identified distinct immunological mechanisms separating early and late-onset disease, and research into cellular immune endophenotypes is beginning to delineate how the immune systems of older and younger patients differ in ways that could shape both disease course and treatment response. The thymus, which plays a central role in the autoimmunity of early-onset disease and shrinks with age, is one obvious point of divergence, and the same research group has separately published a companion meta-analysis on sex distribution, thymic pathology, and autoantibody profiles in very late-onset disease. Inflammatory cytokine networks, which have been shown to be altered in myasthenia gravis, may also interact with the immunosenescence that accompanies aging.

The authors are candid about the limitations of the evidence base and about what future research must fix. Outcome definitions and follow-up durations varied widely across the included studies, which is why the longitudinal findings were summarized qualitatively rather than pooled. They call for future studies to standardize age strata, follow-up periods, treatment exposure, and confounder adjustment, and, crucially, to incorporate geriatric variables that conventional neurology studies have ignored: frailty, multimorbidity, functional outcomes, and polypharmacy. A 70-year-old with myasthenia gravis who is otherwise robust faces very different risks from one who is frail with multiple comorbidities, and the review argues that the field cannot refine prognosis without capturing that distinction.

For now, the practical takeaways are clear. Age of onset matters more than the traditional classification suggests: patients whose disease begins at 65 or older face more than double the odds of presenting with severe, potentially life-threatening generalized weakness, with early swallowing and breathing involvement demanding vigilance in emergency departments and neurology wards alike. But the same evidence shows that a frightening first act does not doom the rest of the story, because long-term disease control in older patients can match that of younger ones when modern immunotherapy is deployed decisively. As the population ages and myasthenia gravis becomes increasingly a disease of the elderly, distinguishing the very late-onset subgroup, monitoring its characteristic early dangers, and treating it with the same therapeutic ambition applied to younger patients may be one of the simplest ways to improve outcomes in an already vulnerable population.

Subject of Research: Clinical severity and long-term outcomes of very late-onset myasthenia gravis

Article Title: Very late-onset myasthenia gravis: a systematic review and meta-analysis of clinical severity and long-term outcomes

Article References: Liampas, I., Demiri, S., Polyviou, A., D’Orsi, A., Siokas, V., Veltsista, D., Dardiotis, E., & Chroni, E. (2026). Very late-onset myasthenia gravis: a systematic review and meta-analysis of clinical severity and long-term outcomes. European Geriatric Medicine. https://doi.org/10.1007/s41999-026-01621-9

Image Credits: AI Generated

DOI: 10.1007/s41999-026-01621-9

Keywords: myasthenia gravis, very late-onset, meta-analysis, systematic review, autoimmune disease, bulbar weakness, myasthenic crisis, immunotherapy, geriatric medicine, prognosis, neuromuscular disease, odds ratio

The disease itself is a malfunction of the neuromuscular junction, the microscopic relay where nerves hand signals to muscles. In myasthenia gravis, IgG antibodies attack proteins on the postsynaptic muscle membrane, most commonly the acetylcholine receptor, and in other patients the muscle-specific kinase MuSK or lipoprotein receptor-related protein 4, known as LRP4. The result is skeletal muscle weakness that fluctuates with use, classically producing drooping eyelids and double vision, but in generalized cases extending to limb, swallowing, and breathing muscles. Roughly 10 percent of cases are paraneoplastic, driven by a thymoma, and autoimmune comorbidity plus heightened vulnerability to infections add further layers of medical complexity. The hallmark worsening of weakness after repetitive exertion, together with the constant anticipation of an exacerbation, contributes a psychological burden that patients consistently rank among the most disabling features of the condition.

Estimating the cost of such a disease is a formidable methodological challenge, and the review is candid about why. Direct costs, meaning hospital care, outpatient visits, drug treatment, and travel related to diagnosis and management, are relatively straightforward to measure from registries and insurance claims. Indirect costs, including lost productivity, welfare payments, patient time spent in medical care, and reduced earnings, require assumptions that vary widely between studies. Intangible costs, the monetary value of lost life-years and diminished quality of life, are rarely calculated at all, even though validated algorithms exist to convert mortality and quality-of-life data into economic terms. Because disease severity ranges from purely ocular symptoms to life-threatening myasthenic crisis, averages conceal enormous individual variation, and because healthcare systems differ so much between countries, the authors deliberately synthesized findings narratively rather than forcing them into a single meta-analysis.

The numbers that emerge are strikingly consistent in their order of magnitude. In the Nordic countries, direct healthcare costs were estimated at roughly €3,500 to €12,000 per patient per year, with similar figures across other European nations and substantially higher values in the United States. Norwegian registry data for 2020 put direct costs at €3,592 per patient, of which hospital care accounted for 87 percent, while prescription drugs added €335. Neighboring countries with comparable health systems reported higher totals: €12,185 in Denmark, €9,036 in Finland, and €5,997 in Sweden, differences the authors attribute partly to methodological choices about what counts as a direct cost. In Norway, direct costs represented only 15 percent of total societal costs, whereas in the other Nordic studies they made up 55 to 70 percent, a discrepancy that illustrates how sensitive these estimates are to accounting frameworks.

Timing matters as much as geography. Across nearly every dataset, costs spike in the first year after diagnosis, when patients typically undergo hospitalization, diagnostic workup, sometimes thymectomy, and aggressive initial therapy with intravenous immunoglobulin or plasma exchange. A Swedish nationwide registry study found healthcare utilization costs were €7,302 higher in the first year after diagnosis than the year before, with 84 percent of that increase directly attributable to the disease, and costs falling markedly in the second year. Italian data showed mean direct costs of €3,771 in year one, €2,827 in year two, and just €255 in year three. German claims data revealed a dramatic treatment gradient, with average inpatient costs of €2,980 for patients on standard therapy but €38,669 for those needing intensified treatment. Refractory disease multiplies the burden: in England, the 5.6 percent of patients classified as treatment-refractory used at least twice the hospitalizations and outpatient visits of non-refractory patients.

The United States sets the global ceiling. A recent analysis of commercially insured patients between 2017 and 2023 found mean annual total healthcare costs of $65,000 for generalized myasthenia gravis, compared with $15,600 for matched controls, with inpatient care the largest component. Hospital discharges for the disease rose more than sixfold between 2003 and 2013 while claims per discharge climbed from $48,024 to $98,795. The most extreme figures attach to acute deterioration: total costs during exacerbations reached $17,113 per patient per month, myasthenic crisis cost $18,640 per month, and each crisis episode carried an estimated price of $47,027. By contrast, a Chinese patient survey reported median annual direct costs of $2,219 against a median household income of $8,759, and a small Indian cohort recorded median direct costs of $720, figures that still represent a heavy burden relative to local incomes.

Indirect costs, the review argues, are chronically undercounted despite being enormous. Norwegian data for 2020 estimated total productivity loss at €9.89 million, or €8,666 per patient, comprising 35 percent of societal costs, with an additional €1,199 per patient lost in reduced income taxation and €1,258 in patient time costs. Danish, Finnish, and Swedish registry studies found indirect costs of €5,463, €2,676, and €2,679 respectively, dominated by early retirement in the first two countries and sick leave in the third. The human dimension behind these figures is sobering. In Germany, 42 percent of non-retired patients reported employment restrictions, averaging 67 absence days in the first year after diagnosis, and among 1,660 members of the German Myasthenia Association, 73 percent of those working at symptom onset reported job limitations, with nearly half unable to work. A Danish cohort found 41 percent of patients took nine or more weeks of sickness absence in their first year, against 3 percent of references. Surveys from Australia, Brazil, Japan, Taiwan, and China consistently show reduced employment, income loss, and activity impairment, and a pooled analysis put overall employment among patients at just 50 percent.

Perhaps the most provocative element of the review is its treatment of intangible costs, which the authors estimate may account for half of all societal costs of the disease. Using Norwegian registry data and national valuation guidelines, they calculated that myasthenia-related deaths caused 73.5 lost quality-adjusted life-years in 2020, 89 percent of that loss concentrated in patients over 60. The average annual loss of health-related quality of life attributable to the disease was 0.22 QALYs versus 0.19 in the general population, translating into €8,428 per patient per year for lost life-years and €4,056 for reduced quality of life, a combined intangible cost of €12,484 annually. These losses rest on well-documented epidemiology: Danish data show a matched mortality ratio of 1.8 for patients, with excess mortality across age groups and especially in the first year after diagnosis, while reduced quality of life is confirmed in cohorts worldwide, greater in women, and normalized only in long-term remission.

The review arrives at a pivotal moment. Complement inhibitors such as eculizumab, approved for myasthenia gravis in 2017, and FcRn blockers such as efgartigimod, approved in 2021, carry listed prices of up to $500,000 per year in some countries, and targeted B and T cell therapies including CAR-T constructs and bispecific antibodies are showing promise in early-phase trials. Most published cost studies predate these drugs, meaning current averages likely understate the coming expense curve. Yet the authors argue the calculus can still favor innovation: a minority of patients with frequent hospitalizations and intensive care needs drives most costs, so expensive new treatments aimed at this group may prove cost-effective if they reduce crises, mortality, and productivity loss. The critical caveat is access, since present pricing means most patients worldwide cannot obtain optimal therapy. Precise, updated, country-specific cost data, the review concludes, are not bureaucratic luxuries but the essential foundation for reimbursement decisions, treatment guidelines, and the start-and-stop criteria that will determine which patients benefit from medicine’s newest and most expensive tools.

Subject of Research: Healthcare costs and societal burden of myasthenia gravis

Article Title: Healthcare costs and burden of myasthenia gravis for patients and society: a systematic review

Article References: Gilhus, N. E., Melsom, S. C., & Bugge, C. (2026). Healthcare costs and burden of myasthenia gravis for patients and society: a systematic review. Journal of Neurology, 273(10), Article 648. https://doi.org/10.1007/s00415-026-14111-6

Image Credits: AI Generated

DOI: 10.1007/s00415-026-14111-6

Keywords: myasthenia gravis, healthcare costs, health economics, neuromuscular disease, autoimmune disease, systematic review, direct costs, indirect costs, quality of life, productivity loss, biologics, health policy

The research, led by Vanessa Campes Dannenberg and Maria L. Castro-Codesal of the University of Alberta, together with colleagues at the Hospital for Sick Children in Toronto and the Alberta Children’s Hospital in Calgary, examined the medical records of 115 children and young people with neuromuscular disorders who were recommended for home non-invasive ventilation, or NIV, between 2010 and 2023. Most of the participants were male, with a median age of 11.8 years at the time of ventilation initiation. The most common diagnoses were Duchenne muscular dystrophy, accounting for 39 percent of the cohort, congenital muscular dystrophies at 19 percent, and spinal muscular atrophy at 14 percent. Nearly every child in the study carried at least one additional chronic condition, with a median of four comorbidities per patient, underscoring how medically complex this population is.

The central question was deceptively simple: when three different sets of polysomnography-based criteria are applied to the same overnight sleep study, do they identify the same children as needing breathing support? The team compared the 2023 guidelines from the American College of Chest Physicians, known as CHEST, against the traditional American Academy of Sleep Medicine, or AASM, definitions of moderate-to-severe obstructive sleep apnea and nocturnal hypoventilation, and against a new set of REM-related criteria proposed by the authors themselves. The CHEST criteria, drawn from a European Respiratory Society statement on pediatric long-term ventilation, flag children whose end-tidal or transcutaneous carbon dioxide exceeds 50 mmHg for at least 2 percent of total sleep time, or rises by 10 mmHg above their waking baseline, or whose oxygen saturation drops below 90 percent for at least 2 percent of sleep time or five continuous minutes.

Those thresholds matter because they are far more sensitive than the older AASM definitions, which require carbon dioxide to exceed 50 mmHg for a full 25 percent of total sleep time before labeling a child as hypoventilating. The results were striking. Only 9 percent of the children met the AASM-based hypoventilation criterion, while the CHEST guidelines identified 25 percent, and the REM-related criteria caught 12 percent. For nocturnal hypoxemia, for which the AASM framework offers no initiation criterion at all, the CHEST guidelines identified 22 percent of the cohort and the REM-related criteria 15 percent. In total, 71 percent of the children met at least one NIV initiation criterion across the three criteria sets, but a meaningful minority were visible only through the newer lenses.

Agreement between the criteria sets, measured with kappa statistics, told a nuanced story. Overall agreement between the CHEST and REM-related criteria was moderate, with a kappa of 0.71, and agreement on nocturnal hypoxemia between those two sets was similarly moderate at 0.69. The strongest agreement, a kappa of 0.86, emerged between the CHEST and AASM criteria on the apnea-hypopnea index, which is unsurprising given that both frameworks use similar thresholds of five or more respiratory events per hour. The divergence, in other words, was not about counting apneas and hypopneas. It was about the slow, silent buildup of carbon dioxide and the dips in oxygen that occur without any discrete respiratory event, particularly during the muscle atonia of REM sleep.

That physiology is the heart of the study’s argument. In children with neuromuscular weakness, breathing during REM sleep depends heavily on the diaphragm, because the intercostal and upper airway muscles lose their tone in that stage. When the diaphragm is also weak, carbon dioxide accumulates and oxygen levels fall, often without producing a single scored apnea. As the disease progresses, these abnormalities spread into non-REM sleep and eventually into wakefulness, culminating in chronic respiratory failure. The authors’ proposed REM-related criteria were designed to capture this earliest phase, and the analysis showed that an additional 11 percent of children met REM-related indications that the AASM-based criteria missed entirely. Thirteen percent of the cohort, twelve children, met no AASM-based criteria at all but satisfied at least one CHEST and one REM-related criterion.

The study also looked at what happened after ventilation began. Ninety-six percent of the children, 111 in total, successfully started NIV, and 73 percent of them sustained the therapy for six to twelve months, the window the researchers chose to avoid the acclimatization period when adherence is typically unstable. Adherence was respectable: children used the machine for a median of six hours per night, and on a median of 60 percent of nights they managed more than four hours of use. Clinician-documented reports from routine visits described improvements in general health in 34 percent of children, better sleep quality in 36 percent, and improved breathing during sleep in 25 percent. Most children avoided emergency department visits, ward admissions, and intensive care during the follow-up period.

Notably, the study found no significant differences in lung function before and after NIV initiation in any of the criteria groups, and no differences in adherence or clinical outcomes between groups. The authors attribute this largely to the substantial overlap among the three groups, since most children met the apnea-hypopnea thresholds common to all criteria sets. They also caution that NIV does not reverse the decline in lung function driven by the underlying disease; at best, it slows the trajectory, and changes are influenced by disease-modifying therapies and the natural history of each disorder. Only about half of the cohort could perform lung function testing that met American Thoracic Society technical standards, further limiting those comparisons.

The findings carry real weight for clinical practice. Earlier work in children with Duchenne muscular dystrophy had already suggested that disease-specific criteria could prompt ventilation for an additional 22 percent of children compared with standard AASM definitions. This study extends that insight to a broader neuromuscular population and adds a physiological rationale: many children show REM-related hypoventilation or hypoxemia with a normal apnea-hypopnea index, and the CHEST guidelines, by lowering the carbon dioxide threshold and adding an explicit hypoxemia criterion, are built to detect exactly that pattern. This matters especially for conditions such as myotonic dystrophy, in which discrete respiratory events are less common but carbon dioxide retention can still be dangerous.

The researchers acknowledge the limits of their retrospective design, their reliance on chart documentation, and the overlap that prevented subgroup comparisons. They also note that future studies may be difficult to conduct, because withholding ventilation until advanced hypoventilation develops would now be ethically questionable. Still, their conclusion is clear and forward-looking: guidelines for children with neuromuscular disease should integrate disease-specific and sleep-stage-specific polysomnographic criteria, watching REM sleep closely for the first signs of failure. Caught early, supported by a mask and a machine at home, these children may avoid the steepest part of the respiratory decline that has long defined their prognosis.

Subject of Research: Polysomnographic criteria for initiating non-invasive ventilation in children with neuromuscular diseases

Article Title: Establishing polysomnographic criteria for initiation of non-invasive ventilation in children with neuromuscular diseases

Article References: Dannenberg, V. C., Amin, R., Anagnostopoulos, G., Adeleye, A., Bendiak, G. N., Kolski, H., & Castro-Codesal, M. L. (2026). Establishing polysomnographic criteria for initiation of non-invasive ventilation in children with neuromuscular diseases. Journal of Clinical Sleep Medicine, 22(1), Article 117. https://doi.org/10.1007/s44470-026-00102-x

Image Credits: AI Generated

DOI: 10.1007/s44470-026-00102-x

Keywords: neuromuscular disease, non-invasive ventilation, polysomnography, REM sleep, sleep-disordered breathing, nocturnal hypoventilation, Duchenne muscular dystrophy, spinal muscular atrophy, pediatric sleep medicine, CHEST guidelines, AASM criteria, nocturnal hypoxemia

Monoclonal gammopathy of clinical significance, abbreviated MGCS, describes a situation in which a clone of plasma cells in the bone marrow produces an abnormal, monoclonal immunoglobulin. Unlike monoclonal gammopathy of undetermined significance, or MGUS, in which the abnormal protein is a harmless laboratory finding, MGCS means the monoclonal protein is actively damaging tissue. Depending on the properties of the antibody, that damage can take many forms: nerve injury, kidney disease, skin changes, amyloid deposition or, as in the cases examined here, muscle disease. The concept, formalized in a landmark 2018 position paper in the journal Blood, implies something clinically crucial: treating the plasma cell clone itself, rather than only the damaged organ, can halt or reverse the disease.

The first of the two conditions, scleromyxedema-associated myopathy, arises in patients with scleromyxedema, a rare sclerosing skin disease characterized by widespread papular and waxy thickened lesions caused by mucin deposits in the dermis. Scleromyxedema is itself almost always linked to an IgG monoclonal gammopathy, and its systemic complications can include neurological and muscular involvement. Muscle weakness in these patients has been reported sporadically since the 1960s and 1970s, but the pathological picture has remained fragmentary. The second condition, VAMMGAS, was only recently characterized in the European Journal of Neurology by a team including several of the same French investigators. It combines progressive muscle weakness, muscle stiffness, vacuolar changes visible on muscle biopsy and a monoclonal gammopathy, but without the characteristic skin disease of scleromyxedema.

To test whether these entities belong to a single disease family, the researchers performed a detailed side-by-side comparison of three patients: two with SAM and one with VAMMGAS. They examined the clinical course, electrophysiological findings, light-microscopic histopathology and, critically, ultrastructural features seen under the electron microscope. They then placed their observations against the backdrop of the published literature on both disorders and on related monoclonal gammopathy-associated myopathies, including sporadic late-onset nemaline myopathy, amyloid myopathy and newly described glycogen storage myopathies linked to plasma cell clones.

The comparison revealed striking common ground. All three patients showed progressive weakness predominantly affecting the proximal muscles, those closest to the trunk, such as the hip and shoulder girdles. Electromyography, the technique that records the electrical activity of muscle fibers through a needle electrode, showed prominent pathological spontaneous activity in all cases. This finding, which reflects irritable, unstable muscle membranes, indicates that the muscle fibers themselves are being injured, and it helps distinguish these myopathic processes from pure nerve disorders. In both conditions, the muscle biopsy showed a myopathy with features suggesting that autophagy, the cellular housekeeping system that digests and recycles damaged components, was not working properly. Autophagy is essential for muscle health; when it falters, fibers accumulate abnormal vacuoles and material that they cannot clear, a pattern familiar to neuromuscular specialists from genetic disorders such as X-linked myopathy with excessive autophagy and from drug toxicities such as colchicine myopathy.

Alongside the autophagy signature, the biopsies carried clear fingerprints of immune activation. The muscle fibers abnormally expressed HLA class I molecules, the same antigen-presenting machinery that flags cells to the immune system, and deposits of C5b-9, the membrane attack complex of the complement cascade, were found on the sarcolemmal membranes of the fibers. These are the kind of findings typically seen in immune-mediated myopathies, where antibodies and complement attack muscle directly or mark it for destruction. In other words, the muscle in both diseases shows simultaneous evidence of a failed intracellular waste-disposal system and an active immune assault on the fiber surface, a combination that is unusual and diagnostically provocative.

There were differences, too, and they may prove just as informative as the similarities. By definition, SAM occurs in the context of scleromyxedema, and the researchers note that the skin disease may occasionally appear only after the muscle symptoms have begun, a sequencing that can delay diagnosis. VAMMGAS, by contrast, is defined by prominent muscle stiffness. The monoclonal protein also differs in a subtle but potentially meaningful way: in SAM the underlying gammopathy is most commonly IgG of the kappa light-chain type, whereas IgG lambda appears to be more frequent in VAMMGAS. On histology, inflammatory infiltrates, actual clusters of immune cells within the muscle tissue, seem to be more characteristic of SAM, while VAMMGAS leans more heavily toward the vacuolar, autophagy-impaired picture. The authors propose that the two diseases occupy different positions on a spectrum running between autophagy dysfunction at one pole and inflammation at the other, with individual patients landing somewhere in between depending on the biology of their particular monoclonal protein.

Why would a single abnormal antibody cause such a strange mixture of cellular pathology? The study does not deliver a definitive mechanism, but the framework it suggests is biologically plausible. Monoclonal immunoglobulins or their light chains are known to interfere with lysosomal function and autophagic flux in other MGCS-related diseases; in amyloid light-chain cardiotoxicity, for example, lysosomal dysfunction and impaired autophagy are established drivers of tissue damage. At the same time, immune complexes formed by monoclonal antibodies can activate complement, explaining the C5b-9 deposits on muscle membranes. Fibroblast growth factor 2 and transforming growth factor beta signaling have been invoked in the skin fibrosis of scleromyxedema, and TGF-beta is also known to epigenetically regulate autophagy, hinting at possible molecular bridges between the fibrosing, inflammatory and autophagic components of the syndrome.

The therapeutic implications may be the most consequential part of the work. Because both conditions appear to sit within the MGCS framework, they seem to respond to two complementary treatment strategies: immunomodulatory approaches, including intravenous immunoglobulin and plasma exchange, and clone-directed therapies that target the plasma cells producing the offending monoclonal protein. Intravenous immunoglobulin has long been a mainstay for the skin disease of scleromyxedema, and plasma exchange has been used successfully in refractory cases, while plasma cell-directed regimens have shown benefit in monoclonal gammopathy-associated scleromyxedema. Recognizing SAM and VAMMGAS as related MGCS manifestations gives clinicians a rationale for combining these approaches and for monitoring the monoclonal protein as a marker of disease activity, rather than treating the muscle in isolation with nonspecific immunosuppression.

For patients, the practical message is one of awareness. Unexplained progressive proximal weakness, especially when accompanied by muscle stiffness, thickened or waxy skin, or an abnormal protein band on serum electrophoresis, should prompt evaluation by a neuromuscular specialist and a hematologist together. The authors emphasize that recognizing the overlapping clinical, neurophysiological and histological features of SAM and VAMMGAS can shorten the diagnostic odyssey and open the door to treatments that address the root cause. With only a handful of cases described worldwide, much remains to be learned, and the researchers themselves frame their conclusions as hypothesis-generating rather than definitive. But the idea that a lone clone of antibody-producing cells can push muscle fibers simultaneously into autophagic failure and immune-mediated injury, and that this process can be caught and treated, marks a genuine step forward in the understanding of rare immune-muscle disease.

Subject of Research: Scleromyxedema-associated myopathy and VAMMGAS as monoclonal gammopathy-associated muscle diseases

Article Title: Scleromyxedema-Associated Myopathy and Vacuolar Myopathy with Monoclonal Gammopathy and Stiffness (VAMMGAS) as manifestations of Monoclonal Gammopathy of Clinical Significance (MGCS): a disease spectrum between autophagy dysfunction and inflammation

Article References: Nicoletti, T., Benveniste, O., Battistella, M., Mahevas, T., Arnulf, B., Stojkovic, T., Staedler, K., Maisonobe, T., Letournel, F., Romero, P., Malfatti, E., Vignon, M., Nadaj-Pakleza, A., Labella, B., Lacene, E., Brochier, G., Evangelista, T., & Leonard-Louis, S. (2026). Scleromyxedema-Associated Myopathy and Vacuolar Myopathy with Monoclonal Gammopathy and Stiffness (VAMMGAS) as manifestations of Monoclonal Gammopathy of Clinical Significance (MGCS): a disease spectrum between autophagy dysfunction and inflammation. Journal of Neurology, 273(10), Article 633. https://doi.org/10.1007/s00415-026-14169-2

Image Credits: AI Generated

DOI: 10.1007/s00415-026-14169-2

Keywords: monoclonal gammopathy, MGCS, scleromyxedema, VAMMGAS, vacuolar myopathy, autophagy, muscle weakness, HLA class I, complement C5b-9, intravenous immunoglobulin, plasma exchange, neuromuscular disease

Centronuclear myopathies are a group of rare inherited disorders defined by progressive muscle wasting and weakness, named for the abnormal positioning of nuclei at the centre of muscle fibres rather than at their periphery. The most common autosomal dominant form is caused by mutations in the DNM2 gene, which encodes dynamin 2, a GTPase enzyme involved in membrane fission, intracellular trafficking and organelle morphology. Roughly 40 different heterozygous DNM2 mutations have been linked to the disease, which accounts for approximately 15 percent of all centronuclear myopathy cases. Severity ranges broadly, from mild late-onset weakness to severe neonatal forms, and no curative therapy currently exists.

In a study published in the Journal of Cachexia, Sarcopenia and Muscle, a research team used the KI-Dnm2 R465W/+ mouse model, which carries a disease-causing mutation analogous to those found in patients, to test whether inhibiting myostatin could counteract the muscle deterioration characteristic of the disease. Myostatin, also known as growth differentiation factor 8, is widely regarded as the master negative regulator of skeletal muscle mass throughout development and adult life. It signals through the activin type IIB receptor, activating the SMAD2/3 pathway, which suppresses the proliferation and differentiation of muscle precursor cells, represses the IGF1-Akt-mTOR anabolic pathway, downregulates muscle-specific genes and promotes E3 ubiquitin ligases involved in protein degradation.

The researchers first mapped the natural course of the disease in these mice using longitudinal magnetic resonance imaging, repeated at 1, 2 and 8 months of age with a high-field 7-Tesla system. Although the knockin mice were viable and grew normally in body size, their leg muscle cross-sectional area lagged dramatically behind healthy littermates. Between 1 and 2 months of age, a critical postnatal growth window, healthy mice expanded their leg muscle cross-sectional area by 1.5-fold, while the mutant mice managed only a 1.2-fold increase. Functional testing revealed that the trouble began even earlier: impaired motor coordination and reduced grip strength were already detectable at 1 month, before measurable muscle growth failure appeared, and histological analysis of the tibialis anterior muscle showed more than 20 percent of fibres displaying the hallmark central NADH-TR staining pattern of the disease at 2 months.

Digging into the molecular roots of this growth failure, the team found a coordinated disruption of multiple homeostatic systems. The number of Pax7-positive satellite cells, the stem-like reservoir that fuses with growing fibres to supply new myonuclei, was significantly reduced, along with MyoD expression, indicating defective myonuclear accretion. At the same time, the translational repressor Eif4ebp1 was upregulated, suggesting suppressed protein synthesis, while FOXO3 and its downstream E3 ligase targets MuRF1, Atrogin-1 and Musa1 were elevated, pointing to accelerated protein breakdown. Autophagy-related transcripts such as Bnip3 and Map1lc3b were paradoxically reduced while P62 and LC3B-I protein accumulated, a signature of impaired autophagic flux. Together, these findings paint centronuclear myopathy not as a single broken pathway but as a global collapse of muscle protein and nuclear homeostasis.

To test whether myostatin was a viable therapeutic target, the researchers crossed the mutant mice with a myostatin knockout line, producing double-mutant animals completely lacking functional myostatin. The results were dramatic. The double-mutant mice gained substantially more body weight, and the mass of the tibialis anterior, quadriceps, extensor digitorum longus and soleus muscles far exceeded even healthy wild-type levels. Critically, grip strength and rotarod performance, which were significantly impaired in the myopathy mice, were fully restored to normal. Because myostatin is absent from embryogenesis onward in these animals, lifelong suppression appears to be integrated into developmental muscle growth programs, including enhanced satellite cell activation and myoblast proliferation, producing stable structural and functional benefits.

Genetic deletion, however, is not a practical option for patients, so the team next turned to pharmacology. They administered a soluble activin type IIB receptor fused to a human IgG1 Fc fragment, a decoy receptor that sequesters both myostatin and activin A in the circulation, by intraperitoneal injection twice weekly at a dose of 5 milligrams per kilogram. Four-week-old mutant mice received the treatment for four consecutive weeks. The intervention produced a marked anabolic effect: tibialis anterior mass was partially restored, quadriceps mass was completely normalized, and gastrocnemius mass actually exceeded wild-type values by the end of treatment. Serum myostatin concentrations rose during therapy, consistent with the decoy receptor prolonging the circulating half-life of the bound hormone and with increased production from newly expanded muscle mass.

But the pharmacological results came with two sobering caveats. First, the muscle gains proved entirely reversible: five weeks after treatment stopped, muscle mass had fallen back to untreated disease levels, indicating that continuous administration would be required to maintain any benefit. Second, and perhaps more importantly, the drug restored size without restoring power. In situ force measurements of the tibialis anterior showed no improvement in maximal absolute or specific force despite the hypertrophy. Molecular analysis explained why: while Akt Ser473 phosphorylation increased, confirming an anabolic signal, the treatment failed to correct the core pathological features of the disease, including elevated E3 ligase expression, impaired autophagic flux, reduced ribosomal and myosin heavy chain transcripts, and dysregulated expression of excitation-contraction coupling genes such as Chrna1, RyR1 and Casq1. Because dynamin 2 is known to organize transverse tubules, the membrane invaginations that transmit electrical signals deep into the fibre, these contractile defects appear intrinsic to the disease and beyond the reach of simply growing bigger fibres.

The contrast between the two strategies carries a clear message for the field. In mice, permanent myostatin inactivation reshapes developmental programs and delivers lasting improvements in both mass and function, whereas transient pharmacological blockade produces short-lived hypertrophy that leaves the underlying contractile and metabolic defects untouched. The authors note that combined myostatin and activin A inhibition may hold particular promise for human medicine, since activin A circulates at higher levels in people than in mice and signals through the same SMAD2/3 axis. Their conclusion is that future therapies for autosomal dominant centronuclear myopathy should be judged not merely by their ability to bulk up muscle, but by whether they durably restore contractile performance, likely in combination with approaches that directly repair the excitation-contraction machinery. The work was supported by AFM-Téléthon through the strategic MyoNeurALP programme.

Subject of Research: Myostatin inhibition therapy for dynamin 2-related centronuclear myopathy

Article Title: Genetic and Pharmacologic Inhibition of Myostatin Restores Muscle Mass in a Dynamin 2‐Related Centronuclear Myopathy Mouse Model

Article References: Anne‐Cécile, D., David, A., Mathias, V., Valentine, A., Chloé, P., Quentin, D., Esra, K., Sidney, C., Emmanuelle, G., Louise, C., Alexandre, G., Josiane, C., Aja, P., Maximilien, B., Baptiste, M., Christophe, H., Schaeffer, L., Olli, R., Marc, B., … Damien, F. (2026). Genetic and Pharmacologic Inhibition of Myostatin Restores Muscle Mass in a Dynamin 2 ‐Related Centronuclear Myopathy Mouse Model. Journal of Cachexia, Sarcopenia and Muscle, 17(5), Article e70338. https://doi.org/10.1002/jcsm.70338

Image Credits: AI Generated

DOI: 10.1002/jcsm.70338

Keywords: centronuclear myopathy, myostatin, dynamin 2, sActRIIB-Fc, muscle mass, muscle force, satellite cells, autophagy, excitation-contraction coupling, mouse model, neuromuscular disease, Akt signalling

High-flow nasal cannula is a deceptively simple piece of technology. Instead of a mask covering the nose and mouth, heated, fully humidified gas is delivered through a wide-bore nasal interface at flow rates of up to 60 liters per minute, with the fraction of inspired oxygen adjusted to the patient’s needs. The therapy provides several physiological advantages: it generates low levels of positive airway pressure, flushes carbon dioxide out of the upper airway’s anatomical dead space, reduces the work of breathing, and improves clearance of secretions. Because it leaves the mouth free, patients can talk, eat, and drink while receiving support, and the open nasal interface dramatically reduces the claustrophobia and skin breakdown that plague mask users. Evidence in other neuromuscular diseases has hinted that patients tolerate it better than conventional ventilation, but data specific to ALS have been scarce, largely confined to small observational studies from high-income tertiary centers at moderate altitudes.

The new study, conducted by a multidisciplinary home respiratory care team, followed 18 ALS patients enrolled between January 2014 and December 2024 in a specialized home care program for neuromuscular disease. All had confirmed ALS, evidence of chronic respiratory failure, and clinician-documented intolerance to non-invasive ventilation attributable to interface problems, claustrophobia, excessive secretions, dysphagia, behavioral intolerance, or anatomical obstacles. The researchers combed electronic medical records for demographic details, comorbidities, arterial blood gas measurements, respiratory muscle strength, functional status, hospitalizations, infections, and mortality, comparing outcomes at the start of high-flow therapy with the last available follow-up.

The cohort tells its own story about how relentlessly ALS advances. The average age at which high-flow nasal cannula was initiated was 65.1 years, roughly eight years after the average age at diagnosis of 57.5. Women made up two-thirds of the group, and the mean body mass index was 23.6 kilograms per square meter. Notably, 61 percent of patients also carried a diagnosis of obstructive sleep apnea, a comorbidity that may compound ventilatory vulnerability. Comorbidities otherwise were sparse: four patients had hypertension, one had diabetes, and none had cancer, thrombotic disease, or autoimmune conditions beyond a single case of rheumatoid arthritis. These are, in other words, patients whose respiratory failure was driven by ALS itself rather than by a burden of other illness.

The pattern of intolerance to masks was revealing. In seven of the 18 cases, intolerance was partial, rooted in difficulty adapting to the interface, claustrophobic sensations, or discomfort with the delivered airflow. Six patients, about a third of the cohort, managed short periods of mask ventilation alternating with high-flow support, using the cannula for an average of about 4.7 hours daily. During the observation period, half of the patients required at least one hospitalization and a third experienced respiratory infections, rates the authors note are comparable to other ALS cohorts. Five patients, 27.8 percent, died during follow-up. The researchers are careful to frame these figures as reflections of advanced disease stage in a population that had already exhausted first-line support, rather than as failures of the high-flow strategy itself.

The physiological findings are the study’s technical core. Before starting therapy, patients showed a mean arterial pH of 7.40, a partial pressure of oxygen of 62.7 millimeters of mercury, a carbon dioxide partial pressure of 36.4 millimeters of mercury, and bicarbonate values ranging from 16 to 29 millimoles per liter. After a period on high-flow cannula, pH ticked up slightly to 7.42, oxygen pressure eased to 59.8 millimeters of mercury, carbon dioxide rose to 42.4 millimeters of mercury, and bicarbonate climbed to 27.8 millimoles per liter. None of these shifts reached statistical significance, and paired analyses confirmed wide confidence intervals spanning zero for every parameter. The authors interpret this stability as clinically meaningful: high-flow nasal cannula does not deliver enough inspiratory pressure support to raise tidal volume or reverse chronic hypercapnia the way mask ventilation can, yet in these carefully selected patients it maintained gas exchange without triggering respiratory acidosis or abrupt deterioration from carbon dioxide retention.

Functional trajectories told a starker story. The Barthel Index, a standard measure of independence in daily activities, fell by an average of 23.3 points, from 35.0 at the start of therapy to 11.7 at the final assessment, a highly significant decline driven chiefly by losses in walking and climbing stairs. The Cruz Roja Functional Classification showed the same slope: at baseline, nearly 78 percent of patients were already at Grades 3 or 4 of physical disability, and by final follow-up more than half had progressed to Grade 5, total dependence, while mild mental impairment rose from 22 percent to 39 percent of the group. Intriguingly, respiratory muscle strength did not follow suit. Maximum inspiratory and expiratory pressures remained essentially unchanged, with p-values of 0.97 and 0.76 respectively. This dissociation, the authors argue, underscores that functional decline in ALS is propelled not only by weakening respiratory muscles but by progressive limb weakness, bulbar dysfunction, and global neurological deterioration.

How do these results sit within the broader literature? The authors point to prior work in neuromuscular disease, including a study by Lionello and colleagues, that likewise documented high patient acceptance of high-flow therapy, with comfort, preserved speech and eating, and reduced claustrophobia cited as decisive advantages. One difference stands out: in that earlier study, three patients receiving continuous 24-hour high-flow support experienced treatment failure, whereas no complications directly attributable to the device were documented in the present cohort. The researchers caution that the descriptive design and small sample make this observation far from definitive, but they suggest it may reflect individualized titration of flow and oxygen and the close multidisciplinary follow-up that a dedicated home care program provides.

The study’s limitations are laid out candidly. A retrospective case series of 18 patients cannot establish causal relationships, and the absence of a comparison group prevents any direct judgment of whether high-flow cannula outperforms persisted mask use or invasive ventilation. Follow-up duration varied by patient because assessments relied on the last recorded clinical evaluation, and treatment discontinuation dates were not systematically documented. Baseline blood gases were drawn during routine care rather than a standardized protocol, so the researchers could not consistently determine whether they were obtained during mask ventilation, how much time elapsed before follow-up measurements, or how long patients had used masks before transitioning. These gaps limit the ability to characterize the longitudinal physiological effects of the therapy or to test whether prior mask exposure shaped tolerance.

Even with those caveats, the report matters for a population with few good options. It provides descriptive, real-world evidence that home-based high-flow nasal cannula is feasible in ALS patients who cannot tolerate masks, that it holds gas exchange steady despite limited ventilatory assistance, and that it may do so without device-attributable complications when embedded in structured multidisciplinary home care. The functional decline observed tracks the natural history of the disease rather than the support modality. The authors call for prospective comparative studies to define more precisely where high-flow therapy belongs in the respiratory management of ALS, but for patients facing the choice between an intolerable mask and an invasive tracheostomy, a comfortable nasal interface that buys stability may represent exactly the middle path the field has been looking for.

Subject of Research: Use of high-flow nasal cannula as home respiratory support in ALS patients intolerant to non-invasive ventilation

Article Title: Use of High‐Flow Nasal Cannula in Amyotrophic Lateral Sclerosis Patients Intolerant to Non‐Invasive Ventilation: A Case Series

Article References: Varon‐Vega, F., Franco Parra, C. E., Adame Ochoa, D. F., Uricoechea, N., Tuta‐Quintero, E., & Martinez Ayala, M. C. (2026). Use of High‐Flow Nasal Cannula in Amyotrophic Lateral Sclerosis Patients Intolerant to Non‐Invasive Ventilation: A Case Series. Respirology Case Reports, 14(9), Article e70744. https://doi.org/10.1002/rcr2.70744

Image Credits: AI Generated

DOI: 10.1002/rcr2.70744

Keywords: amyotrophic lateral sclerosis, high-flow nasal cannula, non-invasive ventilation, chronic respiratory failure, home respiratory care, arterial blood gases, ventilatory support, neuromuscular disease, Barthel Index, case series, respiratory muscle strength, bulbar dysfunction

The case, published in the journal Cancer Reports, documents how progressive proximal muscle weakness and markedly elevated creatine phosphokinase (CPK) preceded any recognizable sign of lymphoma. On examination, the patient demonstrated symmetric weakness of the shoulder and hip girdle muscles, scoring 3 out of 5 on the Medical Research Council strength scale—able to move against gravity but not against resistance. Deep tendon reflexes were reduced, but cranial nerves, sensation, and sphincter function were intact, pointing clinicians toward a primary disease of muscle rather than nerve.

Laboratory workup sharpened the puzzle. Serum CPK, an enzyme released when muscle fibers break down, measured 900 IU/L against a reference ceiling of roughly 195 IU/L. Lactate dehydrogenase and inflammatory markers were also elevated, while a mild anemia hinted at systemic illness. Crucially, the team systematically excluded the usual suspects: antinuclear antibody, myositis-specific antibodies including anti-Jo-1, anti-Mi-2, anti-SRP, and anti-HMGCR were all negative, thyroid function and thyroid autoantibodies were normal, and testing for HIV, hepatitis B, and hepatitis C was negative. Epstein-Barr virus serology showed only evidence of past infection. No autoimmune, endocrine, toxic, or infectious explanation for the muscle injury survived scrutiny.

Electrophysiology added decisive detail. Electromyography recorded short-duration, low-amplitude motor unit potentials with early recruitment in the deltoid, first dorsal interosseous, and tensor fascia lata muscles, accompanied by prominent fibrillation potentials and positive sharp waves—a pattern characteristic of inflammatory or necrotizing myopathy. Nerve conduction studies were essentially normal, with only mild secondary axonal features, confirming that the problem lay in muscle itself rather than in the peripheral nerves supplying it. By this point, the differential diagnosis had narrowed to inflammatory myopathy, paraneoplastic myopathy, and metabolic muscle disease.

The turning point came from imaging. A contrast-enhanced computed tomography scan, obtained during the systemic evaluation, revealed enlarged left axillary lymph nodes measuring 3.5 by 2.4 centimeters along with an enlarged spleen, without focal lesions in the liver or spleen and without mass lesions elsewhere. These findings suggested a systemic lymphoproliferative process and prompted an excisional biopsy of the axillary node in April 2023. Histopathology showed complete effacement of the node’s architecture by a monomorphic population of medium-sized atypical lymphoid cells, studded with mitotic figures and interspersed tingible-body macrophages that produced the classic ‘starry-sky’ pattern—the histological signature of Burkitt lymphoma.

Immunohistochemistry sealed the diagnosis. The malignant cells expressed CD20, CD10, and BCL6, markers of a germinal-center B-cell origin, and the Ki-67 proliferation index approached 100 percent, reflecting the tumor’s hallmark near-maximal division rate. Cytogenetic analysis demonstrated rearrangement of the MYC oncogene, the molecular engine of Burkitt lymphoma. Staging studies—including bone marrow aspiration and biopsy, magnetic resonance imaging of the brain and entire spine, and cerebrospinal fluid cytology—found no marrow or central nervous system involvement, and the patient was classified as having Ann Arbor Stage III disease based on nodal involvement and splenomegaly.

One diagnostic step was deliberately sacrificed to time. Although muscle biopsy is generally considered the gold standard for classifying inflammatory myopathies, the team deferred the procedure because Burkitt lymphoma is among the most rapidly proliferative of all human malignancies, with tumor doubling times measured in days, and any delay in chemotherapy could prove catastrophic. Corticosteroids, notably, had not been given before the onset of weakness or the initial electrodiagnostic studies, ruling out the common confounder of steroid-induced myopathy; they entered the picture only afterward as part of treatment. The diagnosis of probable paraneoplastic myopathy therefore rested on the convergence of clinical findings, electrophysiology, exclusion of alternatives, and—most persuasively—what happened next.

What happened next was a striking, temporally coupled recovery. The patient began intensive therapy with the Hyper-CVAD regimen, alternating courses of cyclophosphamide, vincristine, doxorubicin, and dexamethasone with high-dose methotrexate and cytarabine, combined with rituximab targeting the CD20 antigen and standard central nervous system prophylaxis. After just the first cycle, by May 2023, his muscle strength had improved markedly and serum CPK had fallen from 900 to approximately 400 IU/L. By August 2023, upon completion of the full treatment course, CPK had normalized to 150 IU/L. Follow-up electromyography in September 2023 showed complete resolution of the previously documented myopathic abnormalities—normalized spontaneous activity, motor unit morphology, and recruitment patterns—confirmed by independent review by an experienced neurologist. At his most recent follow-up in March 2026, the patient remained asymptomatic with normal strength and no recurrence of muscle symptoms.

The clinical lesson embedded in this case concerns the phenomenon of paraneoplastic neuromuscular syndromes, in which the immune system’s response to an occult tumor spills over into attack on healthy tissue. Paraneoplastic myopathies are well described alongside solid tumors and certain hematologic malignancies, particularly Hodgkin lymphoma and intravascular large B-cell lymphoma, but their appearance ahead of sporadic Burkitt lymphoma in an immunocompetent adult appears to be exceptionally rare. Proposed mechanisms include cytokine-driven inflammation, molecular mimicry between tumor antigens and skeletal muscle proteins, and broader immune dysregulation orchestrated by the malignancy. These processes can injure muscle before any constitutional symptom, mass effect, or abnormal blood count announces the cancer, making early diagnosis genuinely difficult.

The case also distinguishes itself from prior reports of Burkitt lymphoma touching the nervous system. Earlier publications described paraplegia from spinal epidural disease, Guillain-Barré syndrome, bilateral numb chin syndrome, and oculomotor nerve palsy—all reflecting direct tumor infiltration or cranial and meningeal involvement. This patient, by contrast, had no cranial neuropathy, no sensory deficit, no cerebrospinal fluid malignant cells, and no marrow disease; electromyography pointed squarely at muscle. The neuromuscular symptoms were not a complication of advanced lymphoma but the principal reason he sought care at all. The authors acknowledge the limitations inherent in a single case report without histological confirmation of muscle involvement and with a restricted immunohistochemical panel, but argue that the full constellation of evidence strongly favors an indirect immune-mediated process tied to the lymphoma.

For clinicians, the message is pragmatic: unexplained proximal muscle weakness with elevated CPK should not be reflexively attributed to primary inflammatory myopathy when conventional investigations come back unrevealing. A careful systemic evaluation, including assessment for occult malignancy, may be warranted in atypical cases—and time matters, because Burkitt lymphoma, while ferociously aggressive, is also among the most chemosensitive cancers known. Early recognition of rare paraneoplastic presentations may mean the difference between timely, curative therapy and a fatal delay. In this instance, treating the cancer cured the muscle disease, a sequence that underscores both the diagnostic value of listening carefully to unusual symptoms and the intricate, sometimes treacherous dialogue between tumors and the immune system.

Subject of Research: Paraneoplastic myopathy as the initial presentation of sporadic Burkitt lymphoma in an immunocompetent adult

Article Title: Paraneoplastic Myopathy as a Possible Initial Presentation of Sporadic Burkitt Lymphoma in an Immunocompetent Adult: A Case Report

Article References: Khalafi‐Nezhad, A., Firouzabadi, D., mohammadkarimi, V., & Dehghanian, A. (2026). Paraneoplastic Myopathy as a Possible Initial Presentation of Sporadic Burkitt Lymphoma in an Immunocompetent Adult: A Case Report. Cancer Reports, 9(9), Article e70669. https://doi.org/10.1002/cnr2.70669

Image Credits: AI Generated

DOI: 10.1002/cnr2.70669

Keywords: Burkitt lymphoma, paraneoplastic myopathy, creatine phosphokinase, electromyography, Hyper-CVAD, MYC rearrangement, non-Hodgkin lymphoma, muscle weakness, case report, immune-mediated myopathy, oncology, neuromuscular disease