The Impact Of Thymectomy In Thymomatous And Nonthymomatous Myasthenia Gravis - The Experience Of A Tertiary Center

INTRODUCTION

Thymectomy remains a mainstay of treatment in Thymomatous (T) and Nonthymomatous (nT) Myasthenia Gravis (MG), with improved clinical outcomes and reduced need for medical treatment, however, there is little research regarding long-term follow-up. We aim to assess the impact of surgery on the long-term outcome of patients with MG at our center.

METHODS

Retrospective analyses of MG patients submitted to thymectomy between 2007 and 2017 at the thoracic surgery department of CHUC. Clinical assessment was performed according to the MG Foundation of America (MGFA) Clinical Classification (cMGFA). The follow-up was categorized according to the MGFA Post-intervention Status (MGFA-PIS) and cMGFA. Statistical analysis was performed with SPSS, to a significance level of 5%.

RESULTS

Thirty-seven patients underwent extended thymectomy and 67.6% were female. Median age at diagnosis was 46.68±19.2 years. Most patients (83.8%) had anti-acetylcholine receptor antibodies and 81.1% had generalized forms of MG. Many patients (67.6%) had surgery less than 12 months after the clinical diagnosis. TMG was present in 19 (51.4%) patients. Compared to nTMG, these patients were older (54.06±17.9 vs 40.17±19.4 years) and most were men (52.9% vs 16.7%). We obtained a good outcome in most patients in the first (81.1%), second (86.1%), and fifth (84.8%) year of follow-up. There was a shift towards better prognosis categories in the good outcome group: 9.1% CSR, 3.0% PR, and 66,7% MM in the fifth year. Preoperative medical treatment did not influence the long-term follow-up outcome. A shorter time to surgery (< 12 months) correlated with better outcomes at year 5 (p=0.016).

CONCLUSION

Thymectomy led to a sustained clinical improvement in our cohort, allowing for a reduced need for medication. A shorter time to surgery seems to have a positive influence on long-term prognosis. We expect that an extended follow-up would improve our results.

"O meu coração bate saudável" - Results from a pilot project for health education in Portuguese children

INTRODUCTION AND OBJECTIVES

Childhood offers an excellent window of opportunity to start interventions to promote behavioral changes before unhealthy lifestyles become established, leading to cardiovascular diseases. The goal of this pilot educational project for children is the promotion of healthy lifestyles and cardiovascular health.

METHODS

This project was implemented in 4th grade children and included teacher-led classroom activities, a lesson given by a cardiologist and a practical lesson with dietitians. The teacher received a manual containing information on the topics to be discussed in class with the pupils and the children received a book that addresses cardiovascular risk factors and prevention. The components included were diet (D), physical activity (PA) and human body and heart awareness (BH). At the beginning and at the end of the schoolyear, a questionnaire was applied to the children to assess knowledge (K), attitudes (A) and habits (H) on these topics.

RESULTS

A total of 73 children from an urban public school in Lisbon, in a low to medium income area, participated in the project. Following the intervention, there was a 9.5% increase in the overall KAH score, mainly driven by the PA component (14.5%) followed by the BH component (12.3%). No improvement was observed for component D. The benefits were also more significant in children from a lower income area, suggesting that socioeconomic status is a determinant in the response obtained.

CONCLUSIONS

An educational project for cardiovascular health can be implemented successfully in children aged 9 years, but longer and larger studies are necessary.

A 6-month trial of memantine for nystagmus and associated phenomena in oculopalatal tremor

Introduction

Oculopalatal tremor (OPT) is a late manifestation of a Guillain-Mollaret triangle lesion. Memantine has been shown to improve nystagmus in OPT, but its long-term efficacy and putative distinct effects on each plane of nystagmus and on associated phenomena (e.g., gravity perception) are largely unknown.

Methods

We conducted a 6-month open-label study to evaluate the effect of memantine in OPT patients. Baseline (visit 1), 2 (visit 2), and 6 months (visit 3) assessments included video-oculography, best corrected visual acuity (BCVA), visual function questionnaire (VFQ25), palatal tremor frequency, and subjective visual vertical (SVV). Memantine was titrated to 20 mg per day and stopped after 6 months.

Results

We included six patients (5 females; mean age 68.5+/-9.7). At visit 2, nystagmus improved >50% only along the horizontal plane in two patients, while worsening >50% along the vertical and horizontal planes in 4 and 1 patients, respectively. At visit 3, previous improvement of nystagmus along the horizontal plane in two patients was not sustained, and it further worsened >50% along the vertical plane in 4. The mean vertical velocity and amplitude of nystagmus in the left eye significantly worsened from visit 2 to visit 3 (p = 0.028). Throughout the study, nystagmus frequency remained unchanged (p = 0.074), BCVA improved in both eyes (p = 0.047, p = 0.017), SVV progression was unpredictable (p = 0.513), and the mean VFQ-25 score (p = 0.223) and mean palatal frequency remained unchanged.

Conclusion

The long-term use of memantine 20 mg per day in OPT produced a modest and only transient improvement in nystagmus, predominantly along the horizontal plane. Visual acuity improved, albeit without relevant changes in vision-related quality of life.

Laing early-onset distal myopathy with subsarcolemmal hyaline bodies caused by a novel variant in the MYH7 gene

Myopathies caused by MYH7 gene mutations are clinically and pathologically heterogeneous and, until recently, difficult to diagnose. The availability of NGS panels for hereditary neuromuscular diseases changed our insight regarding their frequency and allowed a better perception of the different phenotypes and morphological abnormalities associated.

We present a male Portuguese patient with the classical phenotype of Laing early-onset distal myopathy (MPD1) beginning at 6 years of age, very slowly progressive, and with a mild to moderate impact on daily life by the age of 56. Muscle biopsy showed a myopathic pattern with hyaline bodies and cores. The NGS panel for structural myopathies identified a novel missense heterozygous variant, c.T4652C (p.Leu1551Pro), in the exon 34 of the MYH7 gene.

LAMA2 gene mutation update: Toward a more comprehensive picture of the laminin-α2 variome and its related phenotypes

Congenital muscular dystrophy type 1A (MDC1A) is one of the main subtypes of early-onset muscle disease, caused by disease-associated variants in the laminin-α2 (LAMA2) gene. MDC1A usually presents as a severe neonatal hypotonia and failure to thrive. Muscle weakness compromises normal motor development, leading to the inability to sit unsupported or to walk independently. The phenotype associated with LAMA2 defects has been expanded to include milder and atypical cases, being now collectively known as LAMA2-related muscular dystrophies (LAMA2-MD). Through an international multicenter collaborative effort, 61 new LAMA2 disease-associated variants were identified in 86 patients, representing the largest number of patients and new disease-causing variants in a single report. The collaborative variant collection was supported by the LOVD-powered LAMA2 gene variant database (https://www.LOVD.nl/LAMA2), updated as part of this work. As of December 2017, the database contains 486 unique LAMA2 variants (309 disease-associated), obtained from direct submissions and literature reports. Database content was systematically reviewed and further insights concerning LAMA2-MD are presented. We focus on the impact of missense changes, especially the c.2461A > C (p.Thr821Pro) variant and its association with late-onset LAMA2-MD. Finally, we report diagnostically challenging cases, highlighting the relevance of modern genetic analysis in the characterization of clinically heterogeneous muscle diseases.

Novel mosaic mutation in the dystrophin gene causing distal asymmetric muscle weakness of the upper limbs and dilated cardiomyopathy

A group of heterogeneous muscle diseases are caused by dystrophin gene (DMD) mutations. We hereby present a male patient with a diagnosis of symptomatic dilated cardiomyopathy at 44 years-old who developed, soon after, weakness of distal right upper limb. At the age of 58, neurological examination revealed severe atrophy of right thenar muscles, flexion contractures on the right elbow, wrist and fingers, bilateral calf hypertrophy, myotatic areflexia in the upper limbs and hyporeflexia in the lower limbs. Manual muscle examination showed distal weakness of right upper limb muscles, severe on abductor pollicis brevis and extensor pollicis longus, and milder on interossei, finger extensors and brachioradialis muscles. Further testing revealed CK of 1500 U/L, a myopathic pattern on electromyography, and myopathic changes on right deltoid muscle biopsy, with immunohistochemistry showing focal sub-expression of dystrophin. Cardiac workup revealed a severe reduction in left ventricular ejection fraction, with a left ventricle of increased dimensions and global hypo-contractibility. A next-generation sequencing based panel for muscular diseases was performed and a nonsense mutation (c.C7525T) was identified in exon 51 of DMD gene, present in 70% of the gene readings (consistent with mosaicism).

Epidemiology of myasthenia gravis in Northern Portugal: Frequency estimates and clinical epidemiological distribution of cases

INTRODUCTION

In this study we estimated the prevalence, incidence, and mortality of myasthenia gravis (MG) in northern Portugal and characterized the clinical features of the patients identified.

METHODS

We used 2 data sources: clinical records from the hospitals and pyridostigmine prescription registers.

RESULTS

On December 31, 2013, we estimated a point prevalence of 111.7 patients per million population. The highest prevalence was observed in the group >65 years of age, especially in men (288.1 per million). During 2013, we estimated an incidence rate of 6.3 per million per year. Among women, the incidence rate was highest in the 15-49-year age group; in men, incidence increased with age up to 22.1 per million in those >65 years old. The MG-related mortality rate was 0.5 per million.

CONCLUSIONS

These figures are in keeping with similar studies and emphasize the importance of diagnosis and management of MG in elderly populations. Muscle Nerve 54: 413-421, 2016.

Multicentric Genome-Wide Association Study for Primary Spontaneous Pneumothorax

Despite elevated incidence and recurrence rates for Primary Spontaneous Pneumothorax (PSP), little is known about its etiology, and the genetics of idiopathic PSP remains unexplored. To identify genetic variants contributing to sporadic PSP risk, we conducted the first PSP genome-wide association study. Two replicate pools of 92 Portuguese PSP cases and of 129 age- and sex-matched controls were allelotyped in triplicate on the Affymetrix Human SNP Array 6.0 arrays. Markers passing quality control were ranked by relative allele score difference between cases and controls (|RAS_diff|), by a novel cluster method and by a combined Z-test. 101 single nucleotide polymorphisms (SNPs) were selected using these three approaches for technical validation by individual genotyping in the discovery dataset. 87 out of 94 successfully tested SNPs were nominally associated in the discovery dataset. Replication of the 87 technically validated SNPs was then carried out in an independent replication dataset of 100 Portuguese cases and 425 controls. The intergenic rs4733649 SNP in chromosome 8 (between LINC00824 and LINC00977) was associated with PSP in the discovery (P = 4.07E-03, OR_C[95% CI] = 1.88[1.22–2.89]), replication (P = 1.50E-02, OR_C[95% CI] = 1.50[1.08–2.09]) and combined datasets (P = 8.61E-05, OR_C[95% CI] = 1.65[1.29–2.13]). This study identified for the first time one genetic risk factor for sporadic PSP, but future studies are warranted to further confirm this finding in other populations and uncover its functional role in PSP pathogenesis.

Autosomal recessive axonal neuropathy with neuromyotonia: a rare entity

BACKGROUND

Autosomal recessive axonal neuropathy with neuromyotonia is a recently described entity associated to the HINT1 gene, encoding histidine triad nucleotide-binding protein 1.

PATIENT

The authors report a Portuguese 16-year-old girl of Roma ethnicity, descendant of consanguineous parents, with progressive distal muscular atrophy and weakness, beginning at age 6. After several years of extensive investigation with inconclusive results, clinical myotonia was identified. Electrophysiologic studies revealed neuromyotonia associated with a severe chronic predominantly motor axonal neuropathy and homozygous mutation (c.334 C > A, p.H112 N) in HINT1 was detected.

CONCLUSION

This report emphasizes the late onset of clinical myotonia essential to the diagnosis.

[Emery-Dreifuss muscular dystrophy: case report]

Emery-Dreifuss muscular dystrophy type 1 (EDMD1) is a familial disease with X-Linked recessive transmission, caused by a mutation in a nuclear envelope protein, emerin. Clinical manifestations usually occur in adolescence and include contractures, muscle atrophy and weakness, and cardiac conduction disturbances. We describe the case of a young male, aged 16, with first-degree atrioventricular (AV) block and limited extension of both forearms. He had elevated CK, and cardiac monitoring showed severe conduction tissue disease, with significant sinus pauses, chronotropic incompetence and periods of AV dissociation during exercise. Immunohistochemical staining using an emerin antibody showed absence of the protein in a fragment of muscle tissue and genetic study identified a mutation associated with EDMD1. Study of his brother, aged 21, also established a diagnosis of EDMD1. Both individuals received a permanent pacemaker but musculoskeletal manifestations at that time did not warrant any other intervention: Screening for certain genetic diseases, including muscular dystrophies, is mandatory following identification of conduction abnormalities in young people.

Limb-girdle muscular dystrophy in a Portuguese patient caused by a mutation in the telethonin gene

Limb-girdle muscular dystrophy 2G is caused by mutations in the telethonin (TCAP) gene in chromosome 17q11-12. This rare form of hereditary muscle disease was originally described in Brazilian patients and was recently identified in Chinese and Moldavian patients. We present the first Portuguese patient with a limb-girdle muscular dystrophy caused by a mutation in the TCAP gene. A Caucasian male, 50 years old, presented in his early twenties, slowly progressive weakness in upper and lower limbs. Neurologic examination revealed severe atrophy and weakness in the muscles of the arms, thighs and legs' anterior compartment. Muscle MRI of the thighs and legs revealed severe atrophy of all the muscles of the thighs and legs' anterolateral compartment, in a symmetrical way. Molecular studies identified the homozygous c.157C > T (p.Gln53X) mutation in exon 2 of the TCAP gene, already described in Brazilian patients.

Deposition and passage of transthyretin through the blood-nerve barrier in recipients of familial amyloid polyneuropathy livers

Familial amyloid polyneuropathy (FAP) is characterized by deposition of mutated transthyretin (TTR) in the peripheral nervous system. Prior to amyloid fibrils, nonfibrillar TTR aggregates are deposited inducing oxidative stress with increased nitration (3-NT). As the major source of TTR is the liver, liver transplantation (LT) is used to halt FAP. Given the shortage of liver donors, domino LT (DLT) using FAP livers is performed. The correlation between TTR deposition in the skin and nerve was tested in biopsies from normal individuals, asymptomatic carriers (FAP 0) and FAP patients; in FAP 0, nonfibrillar TTR was observed both in the skin and nerve in the same individuals; in patients, amyloid was detected in both tissues. The occurrence of amyloidosis in recipients of FAP livers was evaluated 1-7 years after DLT: TTR deposition occurred in the skin 3 years after transplantation either as amyloid or aggregates; in one of the recipients, fibrillar TTR was present in the epineurium 6 years after DLT. Deposits were scarce and 3-NT immunostaining was irrelevant. Nerve biopsies from DLT recipients had no FAP-related neuropathy. Our findings suggest that TTR amyloid formation occurs faster than predicted and that TTR of liver origin can cross the blood-nerve barrier. Recipients of FAP livers should be under surveillance for TTR deposition and tissue damage.