Generalized myasthenia gravis with acetylcholine receptor antibodies: A guidance for treatment.

BACKGROUND: Generalized myasthenia gravis (MG) with antibodies against the acetylcholine receptor is a chronic disease causing muscle weakness. Access to novel treatments warrants authoritative treatment recommendations. The Nordic countries have similar, comprehensive health systems, mandatory health registers, and extensive MG research. METHODS: MG experts and patient representatives from the five Nordic countries formed a working group to prepare treatment guidance for MG based on a systematic literature search and consensus meetings. RESULTS: Pyridostigmine represents the first-line symptomatic treatment, while ambenonium and beta adrenergic agonists are second-line options. Early thymectomy should be undertaken if a thymoma, and in non-thymoma patients up to the age of 50-65 years if not obtaining remission on symptomatic treatment. Most patients need immunosuppressive drug treatment. Combining corticosteroids at the lowest possible dose with azathioprine is recommended, rituximab being an alternative first-line option. Mycophenolate, methotrexate, and tacrolimus represent second-line immunosuppression. Plasma exchange and intravenous immunoglobulin are used for myasthenic crises and acute exacerbations. Novel complement inhibitors and FcRn blockers are effective and fast-acting treatments with promising safety profiles. Their use depends on local availability, refunding policies, and cost-benefit analyses. Adapted physical training is recommended. Planning of pregnancies with optimal treatment, information, and awareness of neonatal MG is necessary. Social support and adaptation of work and daily life activities are recommended. CONCLUSIONS: Successful treatment of MG rests on timely combination of different interventions. Due to spontaneous disease fluctuations, comorbidities, and changes in life conditions, regular long-term specialized follow-up is needed. Most patients do reasonably well but there is room for further improvement. Novel treatments are promising, though subject to restricted access due to costs.

Prevalence and clinical aspects of immigrants with myasthenia gravis in northern Europe.

INTRODUCTION: Multiethnic studies can provide etiological clues toward the genetic and environmental influence of a disease. The aim of this study was to determine prevalence and clinical features of myasthenia gravis (MG) in immigrants compared with native patients in 2 population-based cohorts. METHODS: This cross-sectional study included 843 MG patients (375 from Norway and 468 from the Netherlands). Ethnic background was defined by questionnaires. RESULTS: Among the participating MG patients, 163 of 843 (19.3%) were first or second generation immigrants, mainly from Europe, Asia, and South America. No marked prevalence differences were found between immigrants and native ethnic groups. MG with muscle specific kinase antibodies and MG with thymoma were more frequent in Asian MG immigrants compared with other ethnic groups (8% vs. 0-4%; P < 0.001 and 21% vs. 6-10%; P < 0.001), respectively. CONCLUSIONS: Our findings indicate that Asian immigrant MG patients carry genetic factors or environmental/lifestyle factors which contribute to their specific phenotype, even after migration. Muscle Nerve 55: 819-827, 2017.

Geographical Distribution of Myasthenia Gravis in Northern Europe--Results from a Population-Based Study from Two Countries.

OBJECTIVES: To compare the prevalence of myasthenia gravis (MG) subgroups based on immunological markers and clinical presentation in two geographically complete MG populations in northern Europe. METHODS: This cross-sectional study included all living MG patients in Norway and a regional cohort from the Netherlands. Patients were identified using their hospital registration codes. Medical charts of subjects >16 years were reviewed. Inclusion criteria were clinical MG, a positive antibody test for acetylcholine receptor (AChR MG) or muscle-specific kinase (MuSK MG), or if seronegative MG, confirmed by an electrophysiological test. RESULTS: 1,205 MG patients (534 Norwegians and 671 Dutch) fulfilled the criteria, giving a higher point prevalence in the Netherlands (167/million, 95% CI 155-180) than in Norway (138/million, 95% CI 126-150). In particular, rates of AChR MG (143 vs. 111/million), MuSK MG (6.5 vs. 0.5/million), and ocular phenotype (62 vs. 24/million) were higher in the Netherlands. CONCLUSION: Novel findings are an AChR MG geographical north-south gradient and a 2.6-fold more ocular MG patients in the Netherlands than in Norway. The MuSK MG latitudinal gradient supports the notion of a north-south gradient in Europe, with a higher prevalence in the south. The variation is probably explained by genetic differences between the populations, in addition to environmental interactions.

Outcome predictors of post-COVID conditions in the European Academy of Neurology COVID-19 registry.

Several neurological manifestations are part of the post-COVID condition. We aimed to: (1) evaluate the 6-month outcome in the cohort of patients with neurological manifestations during the COVID-19 acute phase and surviving the infection, and find outcome predictors; (2) define the prevalence and type of neurological symptoms persistent at six months after the infection. Data source was an international registry of patients with COVID-19 infection and neurological symptoms, signs or diagnoses established by the European Academy of Neurology. Functional status at six-month follow-up was measured with the modified Rankin scale (mRS), and defined as: "stable/improved" if the mRS at six months was equal as or lower than the baseline score; "worse" if it was higher than the baseline score. By October 30, 2022, 1,003 lab-confirmed COVID-19 patients were followed up for a median of 6.5 months. Compared to their pre-morbid status, 522 patients (52%) were stable/improved, whereas 465 (46%) were worse (functional status missing for 16). Age, hospitalization, several pre-COVID-19 comorbidities, and COVID-19 general complications were predictors of a worse status. Amongst neurological manifestations, stroke carried the highest risk for worse outcome (OR 5.96), followed by hyperactive delirium (2.8), and peripheral neuropathies (2.37). On the other hand, hyposmia/hypogeusia (0.38), headache (0.40), myalgia (0.45), and COVID-19 vaccination (0.52) were predictors of a favourable prognosis. Persisting neurological symptoms or signs were reported by 316/1003 patients (31.5%), the commonest being fatigue (n = 133), and impaired memory or concentration (n = 103). Our study identified significant long-term prognostic predictors in patients with COVID-19 and neurological manifestations.

Comparison of interictal vestibular function in vestibular migraine vs migraine without vertigo.

BACKGROUND: Patients with vestibular migraine (VM) suffer attacks of vertigo that often occur in isolation from headache attacks. We aimed to assess and compare vestibular function interictally in patients with VM and patients with migraine without vertigo (M). METHODS: Thirty-eight patients diagnosed with definite VM according to the Neuhauser criteria, and 32 patients diagnosed with M according to the International Headache Society criteria were examined between attacks using a broad battery of bedside vestibular tests, a caloric test, and videonystagmography. RESULTS: Overall, 70% of the VM patients and 34% of the M patients showed abnormalities on one or more of the 14 performed vestibular tests (P = .006). Abnormal findings were more frequent in VM than in M patients on Romberg's test, test for voluntary fixation suppression of the vestibular ocular reflex and test for static positional nystagmus (P = .03, .01 and .04, respectively). There were no differences in the distribution of central and peripheral vestibular signs between VM and M patients. CONCLUSIONS: Vestibular abnormalities were present interictally among both VM and M patients, but were found about twice as frequently among VM patients. This may indicate that subclinical vestibular dysfunction is an integral part of migraine pathology in general, and not solely in VM.

Vestibular sensitivity in vestibular migraine: VEMPs and motion sickness susceptibility.

BACKGROUND: Vestibular migraine (VM) has gained recognition as a distinct clinical entity in recent years. The pathophysiology is unclear. Vestibular evoked myogenic potential (VEMP) is a validated method to test the vestibulocollic reflex and peripheral vestibular hypersensitivity to noise. The aim of our study was to evaluate the vestibular function and sensitivity in a series of VM patients in comparison to ordinary migraine (M) patient and healthy controls. METHODS: Thirty-seven patients diagnosed with VM according to the Neuhauser criteria, 32 migraineurs, and 30 healthy persons underwent VEMP testing (response and sound intensity threshold) and a motion sickness susceptibility questionnaire. RESULTS: We found absence of unilateral or bilateral VEMP response at 90 dB normal hearing level (nHL) in 44% of the VM patients, in 25% of the migraineurs, as compared to in 3% of the healthy controls (p = 0.001). The sound intensity threshold and latencies were similar in all the groups. Migraineurs (VM > M) reported more motion sickness than healthy controls (p = 0.006). CONCLUSION: The results indicate more pathology in the VEMP circuitry in migraineurs than in healthy controls. We did not find support for peripheral vestibular hypersensitivity in terms of lower VEMP threshold among VM patients, but they are more sensitive for motion triggers than other migraineurs.

Long-term follow-up, quality of life, and survival of patients with Lambert-Eaton myasthenic syndrome.

OBJECTIVE: To study survival and to characterize long-term functional impairments and health-related quality of life (HRQOL) of patients with Lambert-Eaton myasthenic syndrome (LEMS). METHODS: In this observational study, survival of patients with LEMS, separately for nontumor (NT) and small cell lung cancer (SCLC), was compared to that of the Dutch general population and patients with SCLC. Disease course in patients with LEMS was recorded retrospectively. Several scales for functional impairments and health-related quality of life were assessed. RESULTS: We included 150 patients with LEMS. Survival was similar to that of the general population in 65 patients with NT-LEMS. Tumor survival was significantly longer in 81 patients with SCLC-LEMS compared to patients with non-LEMS SCLC (overall median survival 17 vs 7.0 months, p < 0.0001). At diagnosis, 39 (62%) of 63 patients with complete follow-up data were independent for activities of daily living, improving to 85% at the 1-year follow-up. The physical HRQOL composite score (55.9) was significantly lower than in the general population (76.3, p < 0.0001) and comparable to that of patients with myasthenia gravis (60.5). The mental HRQOL composite score was 71.8 in patients with LEMS, comparable to that of the general population (77.9, p = 0.19) and patients with myasthenia gravis (70.3). CONCLUSIONS: This study shows that patients with NT-LEMS have normal survival. Patients with SCLC-LEMS have an improved tumor survival, even after correction for tumor stage. A majority of patients with LEMS report a stable disease course and remain or become independent for self-care after treatment.

Increased risk for clinical onset of myasthenia gravis during the postpartum period.

OBJECTIVE: To study the risk of clinical onset of myasthenia gravis (MG) in pregnancy and during the first 6 months postpartum because an association between pregnancy or the postpartum period and the onset of autoimmune MG is widely assumed but not proven. METHODS: The design was a cross-sectional population-based cohort study of 2 MG cohorts (Norway and the Netherlands) with 1,038 healthy controls from Norway. Data were obtained on 246 women with MG (age at onset 15-45 years). Data on pregnancy, hormonal factors, and clinical symptoms were collected by a previously validated environmental MG questionnaire. Relative risk of MG onset before, during, and after pregnancy was calculated by multinomial logistic regression for Norwegian women reaching 45 years of age, adjusted for the observed distribution of person-years in the corresponding control group. RESULTS: Of the included women with MG, 13 (11.5%) of the Dutch and 24 (18.0%) of the Norwegian patients had their first myasthenia symptoms during the pregnancy or postpartum period. The postpartum period was confirmed to be significantly associated with the onset of symptoms of MG in Norwegian women with MG (relative risk 5.5, 95% confidence interval 2.6-11.6). The risk was highest after the first childbirth. CONCLUSIONS: Women have a high-risk period for the onset of clinical symptoms of MG in the postpartum period, in particular after the first childbirth. Future studies should aim at elucidating the role of the hormonal-immunological-genetic interaction in the pathogenesis of MG.