Diagnosis Of Myasthenia Gravis Research Articles

Heavy Duty

A 54-year-old woman with myopia, hypothyroidism, and asthma presented with intermittent double vision. Serum was positive for anti-low density lipoprotein receptor-related protein 4 (LRP4) antibodies suggesting the diagnosis of myasthenia gravis. There was no improvement with pyridostigmine, prednisone, or azathioprine. Over time her double vision became constant, and she was noted to have mild limitation of abduction in both eyes with an esotropia, left hypotropia, and excyclotorsion. Magnetic resonance imaging showed nasal displacement of the superior rectus and inferior rectus muscles, inferior displacement of the lateral rectus muscles and superotemporal globe prolapse consistent with heavy eye syndrome (HES). The differential diagnosis, clinical and radiological manifestations of HES are discussed.

A Dual Diagnosis of Myasthenia Gravis and Sjogren’s Syndrome in a Hispanic Patient: A Case-based Discussion of Clinical Findings, Therapeutic Implications, and Culturally Competent Care

The co-occurrence of myasthenia gravis (MG) and Sjogren's syndrome (SS) in a young, Hispanic, female patient underscores the diagnostic and therapeutic complexities inherent in autoimmune disorders. MG, a rare neuromuscular disorder characterized by autoantibodies impairing neuromuscular transmission, leads to variable muscle weakness and fatigue, notably affecting ocular and bulbar muscles. SS, an autoimmune condition with systemic manifestations, primarily affects secretory glands, resulting in symptoms such as xerostomia and xerophthalmia. Both conditions have higher prevalence rates in females, with MG particularly affecting young women under 40. Herein we present a case report and case-based discussion on diagnostic and management challenges of these two autoimmune conditions while highlighting issues specific to the Hispanic and underrepresented populations. Our goal is to highlight the intricate interplay between these two autoimmune pathologies to allow for more rapid recognition and reduce delay in diagnosis.

Fiber endoscopic evaluation of swallowing (FEES) - an important tool for diagnosing myasthenia gravis

A 76-year old man was admitted with a globus sensation and weight loss for further investigations to our geriatric ward. A gastroscopic evaluation executed before had been unremarkable. Physical examination was unremarkable, including a neurological examination. All radiological findings (computer tomography of chest, abdomen and neck) were unremarkable. In a FEES investigation we found retentions and a reduction of frequency of swallowing after a while. During the investigation the patient complained about a muscular weakness in his neck. The assumed diagnosis of a myasthenia gravis was confirmed by antibodies against acetylcholine receptors and a decrement in repetitive irritation of the orbicularis and trapezius muscle. FEES can be a valid diagnosis tool for a pharyngeal type of a myasthenia gravis.

Spontaneous development of myasthenia gravis and myositis following treatment with pembrolizumab: a case report

BackgroundImmune checkpoint inhibitors are a relatively new advancement in the world of cancer therapy. As such, their adverse effects have yet to be fully understood, with only recent literature documenting autoimmune phenomena secondary to their utilization. Specific immune checkpoint inhibitors have recently been linked with the development of myasthenia gravis, which is classically known to manifest spontaneously in patients. Given the relative rarity of this presentation, the risk of misdiagnosis and subsequent mortality and morbidity is concerning.Case presentationWe discuss the case of a 73-year-old male who presented with clinical symptoms of myasthenia gravis and myositis shortly after beginning treatment with Pembrolizumab. The diagnosis of myasthenia gravis was initially missed at an outside hospital, which delayed initiation of proper treatment.ConclusionWhile the incidence of “de-novo” diseases secondary to immune checkpoint inhibitors might be increasing, guidelines regarding best treatment options do not yet exist, leaving many providers at a loss when faced with making clinical decisions surrounding patients with De novo myasthenia gravis. Thus, our goal is to underscore the importance of early recognition of this disease, and emphasize the need for a standard of care as immune checkpoint inhibitors usage becomes more prevalent.

Accuracy of Repetitive Ocular Vestibular-Evoked Myogenic Potentials to Diagnose Myasthenia Gravis in Patients With Ptosis or Diplopia.

We developed repetitive ocular vestibular-evoked myogenic potentials (roVEMP) as an electrophysiologic test that allows us to elicit the characteristic decrement of extraocular muscles in patients with ocular myasthenia gravis (OMG). Case-control studies demonstrated that roVEMP reliably differentiates patients with OMG from healthy controls. We now aimed to evaluate the diagnostic accuracy of roVEMP for OMG diagnosis in patients with ptosis and/or diplopia. In this blinded prospective diagnostic accuracy trial, we compared roVEMP in 89 consecutive patients presenting with ptosis and/or diplopia suspicious of OMG with a multimodal diagnostic approach, including clinical examination, antibodies, edrophonium testing, repetitive nerve stimulation of accessory and facial nerves, and single-fiber EMG (SFEMG). We calculated the roVEMP decrement as the ratio between the mean of the first 2 responses compared with the mean of the sixth-ninth responses in the train and used cutoff of >9% (unilateral decrement) in a 30 Hz stimulation paradigm. Following a complete diagnostic work-up, 39 patients (44%) were diagnosed with ocular MG, while 50 patients (56%) had various other neuro-ophthalmologic conditions, but not MG (non-MG). roVEMP yielded 88.2% sensitivity, 30.2% specificity, 50% positive predictive value (PPV), and 76.5% negative predictive value (NPV). For comparison, SFEMG resulted in 75% sensitivity, 56% specificity, 55.1% PPV, and 75.7% NPV. All other diagnostic tests (except for the ice pack test) also yielded significantly higher positive results in patients with MG compared with non-MG. The study revealed a high sensitivity of 88.2% for roVEMP in OMG, but specificity and PPV were too low to allow for the OMG diagnosis as a single test. Thus, differentiating ocular MG from other neuro-ophthalmologic conditions remains challenging, and the highest diagnostic accuracy is still obtained by a multimodal approach. In this study, roVEMP can complement the diagnostic armamentarium for the diagnosis of MG. This study provides Class I evidence that in patients with diplopia and ptosis, roVEMP alone does not accurately distinguish MG from non-MG disorders. ClinicalTrials.gov: NCT03049956.

Screening for immune-related biomarkers associated with myasthenia gravis and dilated cardiomyopathy based on bioinformatics analysis and machine learning

BackgroundWe aim to investigate genes associated with myasthenia gravis (MG), specifically those potentially implicated in the pathogenesis of dilated cardiomyopathy (DCM). Additionally, we seek to identify potential biomarkers for diagnosing myasthenia gravis co-occurring with DCM. MethodsWe obtained two expression profiling datasets related to DCM and MG from the Gene Expression Omnibus (GEO). Subsequently, we conducted differential gene expression analysis and weighted gene co-expression network analysis (WGCNA) on these datasets. The genes exhibiting differential expression common to both DCM and MG were employed for protein-protein interaction (PPI), Gene Ontology (GO) enrichment analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Additionally, machine learning techniques were employed to identify potential biomarkers and develop a diagnostic nomogram for predicting MG-associated DCM. Subsequently, the machine learning results underwent validation using an external dataset. Finally, gene set enrichment analysis (GSEA) and machine algorithm analysis were conducted on pivotal model genes to further elucidate their potential mechanisms in MG-associated DCM. ResultsIn our analysis of both DCM and MG datasets, we identified 2641 critical module genes and 11 differentially expressed genes shared between the two conditions. Enrichment analysis disclosed that these 11 genes primarily pertain to inflammation and immune regulation. Connectivity map (CMAP) analysis pinpointed SB-216763 as a potential drug for DCM treatment. The results from machine learning indicated the substantial diagnostic value of midline 1 interacting protein1 (MID1IP1) and PI3K-interacting protein 1 (PIK3IP1) in MG-associated DCM. These two hub genes were chosen as candidate biomarkers and employed to formulate a diagnostic nomogram with optimal diagnostic performance through machine learning. Simultaneously, single-gene GSEA results and immune cell infiltration analysis unveiled immune dysregulation in both DCM and MG, with MID1IP1 and PIK3IP1 showing significant associations with invasive immune cells. ConclusionWe have elucidated the inflammatory and immune pathways associated with MG-related DCM and formulated a diagnostic nomogram for DCM utilizing MID1IP1/PIK3IP1. This contribution offers novel insights for prospective diagnostic approaches and therapeutic interventions in the context of MG coexisting with DCM.

Small extracellular vesicle microRNAs in pediatric myasthenia gravis plasma and skeletal muscle.

The diagnosis of myasthenia gravis (MG) in children remains difficult. Circulating small extracellular vesicle (sEV)-derived miRNAs (sEV-miRNAs) have been recognized as biomarkers of various diseases and can be excreted by different cell types. These biomarker candidates also play a vital role in autoimmune diseases via intercellular communication. In the present study, we used sEV isolation and purification methods to extract the plasma-derived sEV-miRNAs from children with MG and healthy controls. A small RNA sequencing analysis confirmed the miRNA expression features in plasma-derived sEVs from MG patients. The miRNA expression analysis in vitro was determined using microarray analysis. The enrichment and network analyses of altered sEV-miRNAs were performed using miRNA databases and Database for Annotation, Visualization, and Integrated Discovery website. Quantitative real-time polymerase chain reaction was performed for validation of sEV-miRNA. The diagnostic power of altered sEV-miRNAs was evaluated using receiver operating characteristic curve analyses. Twenty-four sEV-miRNAs with altered expression level were identified between groups by DESeq2 method. The miRNAs were extracted from the sEVs, which were isolated from human primary skeletal muscle cell culture treated with mAb198. The target genes and enriched pathways of sEV-miRNAs partially overlapped between cell supernatant and plasma samples. The significantly downregulated miR-143-3p was validated in quantitative real-time polymerase chain reaction analysis. For the first time, we report that plasma-derived sEV-miRNAs may act as novel circulating biomarkers and therapeutic targets in pediatric MG.

Accuracy of prostigmin tests in the diagnosis of myasthenia gravis: a meta-analysis.

Myasthenia gravis (MG) is an acquired autoimmune disease diagnosed based on clinical manifestations, muscle fatigue tests, prostigmin tests, serum antibody tests, and neuroelectrophysiological examination. This study conducted a comprehensive search of PubMed, Web of Science, Scopus, Ovid, Embase, Cochrane Library, China National Knowledge Infrastructure, WanFang, Chinese Periodical Database, Chinese Bio-Medicine Database, VIP, and DuXiu Database to identify relevant studies on the accuracy of prostigmin tests for diagnosing MG, covering publications from 1941 to 2021. Ten studies met the inclusion criteria and were included in the meta-analysis. The analysis found no heterogeneity caused by threshold effects but identified heterogeneity due to non-threshold effects. The combined sensitivity was 0.861 (95% CI: 0.831-0.888), and the combined specificity was 0.844 (95% CI: 0.816-0.870). The combined positive likelihood ratio was 5.496 (95% CI: 1.454-20.77), and the combined negative likelihood ratio was 0.237 (95% CI: 0.123-0.455). The area under the curve for diagnostic accuracy was 0.88 (95% CI: 0.84-0.90), with Q* = 0.8520. The combined diagnostic odds ratio was 19.344 (95% CI: 4.327-86.488). In conclusion, the prostigmin test demonstrated good diagnostic value for MG.

Study on the clinical and electrophysiological characteristics of nerve function in myasthenia gravis patients in Vietnam.

In Vietnam, there is limited research on the role of nerve conduction in myasthenia gravis and its association with clinical features. This study aims to describe the electrophysiological features in patients with myasthenia gravis. This descriptive study was conducted from September 2019 to December 2021. The study included 33 myasthenia gravis patients who sought medical consultation or received inpatient treatment during this period. The Myasthenia Gravis Foundation of America classifies myasthenia gravis into five groups: I, IIa, IIb, IIIa, IIIb, IVa, IVb, and V. Notably, Group I involves pure ocular weakness, whereas Group a primarily impacts limb and axial muscles, and Group b mainly affects bulbar and respiratory muscles. The study revealed that motor and sensory nerve conduction in the upper and lower limbs were within normal limits for the patient group under evaluation. Repetitive nerve stimulation testing at a frequency of 3 Hz showed positive results in 66.7% of myasthenia gravis patients. Myasthenia gravis patients displayed distinct clinical symptoms, with ptosis being the most common (87.9%). Myasthenia Gravis Foundation of America classification indicated the highest proportion in subgroup IIa (24.2%), with myasthenia gravis predominating in limb and axial muscles (Group a) observed in 51.5% of cases. Needle electromyography showed no abnormalities in myasthenia gravis patients. There was an association between acetylcholine receptor antibody titers and the results of the 3 Hz repetitive nerve stimulation test in myasthenia gravis patients, with a significance of p = 0.002. Nerve conduction studies should be performed in patients with suspected neuromuscular disorders to aid in differential diagnosis and definitive diagnosis of myasthenia gravis.

Hypotension as a first presentation of myasthenia gravis in an elderly patient scheduled for cervical disc surgery: a case report

Myasthenia gravis presents with progressive skeletal muscle weakness. The disease can affect any group of muscles, along with the proximal limb and neck musculature. Elderly patients, especially those over 60 y of age, frequently face extensive delays in diagnosis, or are misdiagnosed, as the symptoms may be erroneously attributed to different other causes frequently seen in this age group, such as degenerative joint disease, disk herniation, osteoporotic vertebral fractures, or metastases. We present a case of a 61-year-old male patient with significant medical records of hypertension, who presented with neck pain for a few months, posted for cervical disc surgery at C6-7 with cage fixation. Two attempts for general anesthesia induction were complicated by severe hypotension. He was evaluated with low-frequency repetitive stimulation, Acetyl-choline receptor antibody, and P/Q calcium channel antibodies. The low-frequency Repetitive Nerve Stimulation (RNS) showed a severe reduced response that was corrected after rest, which was consistent with the diagnosis of myasthenia gravis.
 Key words: Myasthenia; Pain, Neck; Hypotension; Weakness
 Citation: Seyam SH, Ali MA, Razein H, Elkousy I, Schandran SB. Hypotension as a first presentation of myasthenia gravis in an elderly patient scheduled for cervical disc surgery: a case report. Anaesth. pain intensive care 2023;27(6):763−767; DOI: 10.35975/apic.v27i6.2351
 Received: July 08, 2023; Revised: September 16, 2023; Accepted: October 09, 2023

Myasthenia gravis and the role of the veterinary nurse

Myasthenia is a syndrome of impaired neuromuscular transmission which can affect dogs and cats. There are two common forms, an autoimmune form where antibodies work against the neuromuscular junction – myasthenia gravis – and a rare, congenital form where the patient is born with an impairment at the neuromuscular junction, for example, they are born with too few acetylcholine receptors. This article focuses on myasthenia gravis. Patients with myasthenia gravis often also develop secondary pathologies such as megaoesophagus and aspiration pneumonia, requiring intensive supportive care from the veterinary team while hospitalised, owner counselling and support being paramount. This article describes the causes, diagnosis and treatment alongside nursing considerations for the myasthenia gravis patient and a brief discussion about future developments around the disease to help the veterinary nurse to be able to assist in better patient outcomes following a diagnosis of myasthenia gravis.

A real-life experience of serological diagnosis of myasthenia gravis with testing of more than five thousand sera referred for diagnosis purpose

A real-life experience of serological diagnosis of myasthenia gravis with testing of more than five thousand sera referred for diagnosis purpose

Time to diagnosis of myasthenia gravis: A tertiary care center analysis

Time to diagnosis of myasthenia gravis: A tertiary care center analysis

Diagnostic challenges in myasthenia gravis: a clinical approach

The development of antibody tests and neurophysiological techniques have aided in confirming the diagnosis of myasthenia gravis (MG) over the years. However, there still remains an unmet diagnostic need in the subgroup of MG patients with weakness restricted to ocular muscles (OMG) as routine diagnostic tests are less sensitive in this group: around 50% of these patients have no positive antibody test and around 71% have no significant decrement with repetitive stimulation EMG. Moreover, virtually all disorders that can cause a pupil-sparing ptosis or diplopia have been reported to be confused with OMG. Among the most mentioned mimicks for OMG are (concomitant) Graves ophtalmopathy, cranial nerve palsies, ocular tendinomuscular deficits (such as levator dehiscence), myopathy, demyelinating disease and stroke. Diagnostic delay and confusion of OMG with mimicking disorders might lead to a worse prognosis due to a possible increased risk of generalization of disease and the need of emergency treatments. A careful clinical follow-up of patients with suspected OMG by systematically assessing changes in ocular weakness patterns between visits can aid in confirming the diagnosis. In addition, the ice pack test can be a diagnostic aid in cases of both evident ptosis as ophtalmoparesis. In the foreseeable future, cell-based assays (CBA) might aid in the diagnostic confirmation of OMG. There is a need of studies that investigates the yield of new and not-routinely used diagnostic tests in suspected OMG with negative antibody and inconclusive EMG and SF-EMG, such as the repetitive ocular vestibular evoked myogenic potentials (RoVEMP) test and CBA. Lastly, the effect of early immunosuppressive treatment should be further investigated in OMG.

The change of systemic inflammation response index in the treatment of patients with myasthenia gravis undergoing thymectomy: A retrospective, follow-up study

Background: This study aims to investigate the role of neutrophil-tolymphocyte ratio, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, and systemic inflammation response index in patients with myasthenia gravis, thymomas and thymic hyperplasia and to identify the relationship between the inflammation response and disease activity. Methods: Between January 2010 and December 2018, a total of 97 patients (71 males, 26 females; mean age: 36.7±16.3 years; range, 15 to 76 years) who underwent extended thymectomy with the diagnosis of myasthenia gravis were retrospectively analyzed. The patients were divided into two groups as the patient group (n=42) and the control group (n=55). Neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, monocyteto-lymphocyte ratio, and systemic inflammation response index were measured one day prior to and one month after surgery. Results: The patients with thymoma were older with a higher mean pre-systemic inflammation response index value. Preoperative systemic inflammation response index, neutrophil-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio were significantly higher in patients with thymoma. A preoperative systemic inflammation response index value of less than 0.62 was accepted to indicate thymic hyperplasia and a postoperative systemic inflammation response index value higher than 2.94 was indicative of thymoma. In myasthenic patients whose steroid dose was increased and/or remained the same at the first month after surgery, postoperative monocyte-to-lymphocyte ratio and systemic inflammation response index values were found to be higher compared to preoperative values (p=0.006 and p=0.032, respectively). Patients whose pyridostigmine dose was increased and/or remained the same had significantly higher systemic inflammation response index values postoperatively (p=0.029). Conclusion: The precise cut-off values of systemic inflammation response index may be helpful for the surgeon to predict the surgical outcome and post-systemic inflammation response index may be a predictive marker for estimating postoperative treatment changes.

Serum amino acid profiles in patients with myasthenia gravis

Myasthenia gravis (MG) is an autoimmune disease characterized by weakness and rapid fatigue. Diagnostic methods used for myasthenia gravis are not conclusive and satisfactory, therefore it is necessary to develop reliable tools to help diagnose myasthenia gravis as early as possible. The aim of the study was to use HPLC–MS in conjunction with multivariate statistical analyses to investigate changes in the amino acid metabolic profiles between myasthenia gravis patients compared and controls. In addition, the effect of treatment regimens and myasthenia gravis type, on the observed changes in amino acid metabolic profiles were assessed. Serum levels of 29 amino acids were determined in 2 groups of individuals—28 patients with myasthenia gravis and 53 control subjects (CS). The results of our study indicate that serum levels of several amino acids in patients with myasthenia gravis changed significantly compared to the control group. Statistical analysis revealed differences between amino acids concentration in patients with different therapeutic scheme. In conclusion, amino acids may be involved in mechanisms underlying myasthenia gravis pathogenesis as well as may be potential biomarkers in MG patients diagnosis. However, considering the multifactorial, heterogenous and complex nature of this disease, validation on a larger study sample in further research is required before application into diagnostic practice.

A multicentre, prospective, double-blind study comparing the accuracy of autoantibody diagnostic assays in myasthenia gravis: the SCREAM study

Laboratory determination of autoantibodies against acetylcholine receptor (AChR), muscle-specific kinase (MuSK) and other autoantigens have been integrated into the diagnosis of myasthenia gravis (MG). However, evidence supporting the selection of methodologies is lacking. In this prospective, multicentre cohort study, we recruited patients with suspected MG to evaluate the diagnostic accuracy of cell-based assay (CBA), radioimmunoprecipitation assay (RIPA) and enzyme-linked immunosorbent assay (ELISA) in detecting AChR and MuSK autoantibodies. This study is registered with www.clinicaltrials.gov, number NCT05219097. 2272 eligible participants were recruited, including 2043MG, 229 non-MG subjects. AChR antibodies were detected in 1478, 1310, and 1280 out of a total of 2043MG patients by CBA, RIPA, and ELISA, respectively; sensitivity, 72.3% (95% CI, 70.3-74.3), 64.1% (95% CI, 62.0-66.2), 62.7% (95% CI, 60.5-64.8); specificity, 97.8% (95% CI, 95.0-99.3), 97.8% (95% CI, 95.0-99.3), 94.8% (95% CI, 91.9-97.7). MuSK antibodies were found in 59, 50, and 54 from 2043MG patients by CBA, RIPA and ELISA, respectively; sensitivity, 2.9% (95% CI, 2.2-3.7), 2.4% (95% CI, 1.8-3.2), 2.6% (95% CI, 2.0-3.4); specificity, 100% (95% CI, 98.4-100), 100% (95% CI, 98.4-100), and 99.1% (95% CI, 96.9-99.9). The area under the curve of AChR antibodies tested by CBA was 0.858, and there were statistical differences with RIPA (0.843; p=0.03) and ELISA (0.809; p<0.0001). CBA has a higher diagnostic accuracy compared to RIPA or ELISA in detecting AChR and MuSK autoantibodies for MG diagnosis. New Terrain Biotechnology, Inc., Tianjin, China.

Detection of Antibodies against the Acetylcholine Receptor in Patients with Myasthenia Gravis: A Comparison of Two Enzyme Immunoassays and a Fixed Cell-Based Assay.

The detection of serum anti-acetylcholine receptor (AChR) antibodies is currently an important tool for diagnosing myasthenia gravis (MG) since they are present in about 85% of MG patients. Many serological tests are now available. Nevertheless, results from these tests can be different in some patients. The aim of this study is to compare the sensitivity of a commercially available fixed cell-based assay (F-CBA) to that of enzyme-linked immunosorbent assay (ELISA) kits for anti-AChR detection in patients with a diagnosis of MG. Overall, 143 patients with a confirmed MG diagnosis were included in the study. The detection and measurement of serum anti-AChR antibodies were performed by three analytical methods, namely, a competitive ELISA (cELISA), an indirect ELISA (iELISA), and an F-CBA, according to the manufacturers' instructions. Anti-AChR antibody titers were positive in 94/143 (66%) using the cELISA, in 75/143 (52%) using the iELISA and in 61/143 (43%) using the F-CBA (adult and/or fetal). Method agreement, evaluated by concordant pairs and Cohen's kappa, was as follows: cELISA-iELISA: 110/143 (77%), k = 0.53 (95%CI 0.40-0.66); cELISA-F-CBA: 108/143 (76%), k = 0.53 (95%CI 0.41-0.66); iELISA-F-CBA: 121/143 (85%), k = 0.70 (95%CI 0.57-0.80). Our findings show that the cELISA has better analytical performance than the iELISA and F-CBA. However, the iELISA and F-CBA show the highest concordance.

New diagnosis of myasthenia gravis in the third trimester – A case report

Myasthenia gravis (MG) is an acquired autoimmune disorder of the neuromuscular junction with an annual incidence rate of 2 to 21 per million. A 25-year-old primiparous woman with no significant medical history presented for a routine antenatal appointment at 37weeks of gestation. She reported a two-week history of transient diplopia and a five-month history of fluctuating weakness in her proximal limbs. Pertinent neurological exam findings included right upper limb flaccidity, and bilateral upper and lower limb weakness more pronounced in the upper limbs and in proximal muscle groups. Cranial nerves III, IV and VI showed mild restriction in all directions, with diplopia in horizontal and downwards gaze. Following one week of investigations, including spirometry, magnetic resonance imaging of brain and spine, and needle electromyography, she was diagnosed with MuSK (anti-muscle-specific tyrosine kinase antibodies) associated myasthenia gravis. Potential complications in this context included myasthenic crisis, delivery complications, and transient neonatal myasthenia gravis. She was initially treated with 5days of plasmapheresis and prednisone. She proceeded to have an elective caesarean section for unstable lie at 39weeks of gestation under combined spinal/epidural anaesthesia without complications. The baby boy was born in good health, was monitored over four days and did not display signs of myasthenia gravis. This case outlines the rare occurrence of newly diagnosed myasthenia gravis in pregnancy, the complexities of management, and need for early multidisciplinary care.

Utility of Repetitive Nerve Stimulation in the Diagnosis of Myasthenia Gravis in the Inpatient Setting.

Sensitivity and specificity of Repetitive Nerve Stimulation (RNS) is typically reported from outpatient centers, and we hypothesized that these values might not apply to hospitalized patients with higher grades of weakness. RNS may be helpful in rapidly confirming diagnosis of myasthenia gravis (MG) in the inpatient setting, as results from confirmatory antibody testing are often delayed. We sought to characterize the sensitivity and specificity of RNS in the inpatient setting to assist in the early diagnosis of MG. We performed a retrospective analysis of all adult patients who had inpatient RNS at our center from 2016 to 2021. Inclusion criteria included RNS performed at least at one site and a neurological evaluation which prompted an electrodiagnostic study to evaluate for neuromuscular junction (NMJ) pathology. Descriptive statistics and Fisher exact analysis were performed. Of the 32 identified hospitalized patients, 6 had greater than 10% decrement on slow RNS, confirming NMJ dysfunction. Five were diagnosed with MG, and 1 with Lambert-Eaton myasthenic syndrome. Of the 26 patients with normal RNS, 25 ultimately had alternative causes of weakness. One was later diagnosed as seronegative MG based on clinical improvement with acetylcholinesterase inhibitors. In our inpatient population, the overall sensitivity and specificity of RNS were 83.3% and 96.2% respectively. There was a statistically significant association between a positive RNS and diagnosis of MG (P = .0002). RNS is a highly sensitive and specific test for the diagnosis of MG in an inpatient setting, and these results are likely more rapidly available compared to antibody testing.