Palatal prolapse during nasal expiration in patients with myasthenia gravis.

INTRODUCTION/AIMS: We have encountered patients with myasthenia gravis (MG) who exhibited palatal prolapse (PP) during nasal expiration in the supine position while awake. This may be an overlooked cause of dyspnea in MG patients. This study aimed to examine and describe the characteristics of MG patients with PP. METHODS: We reviewed the medical records of 183 consecutive patients who were diagnosed with MG in our hospital from 2012 to 2021. Thirty-two patients underwent laryngoscopy because of bulbar symptoms. Eight of these patients (25%) exhibited PP on laryngoscopy. Clinical features of these eight patients were retrospectively characterized. RESULTS: Median age of the eight patients with PP was 70 years. Six were men. Median body mass index was 21.6 kg/m2 . All patients exhibited PP in the supine position but not the sitting position. Although no patient had abnormal findings on spirometry nor chest computed tomography, six reported dyspnea or difficulty with nasal expiration only in the supine position. PP improved in all four patients who underwent edrophonium testing. All eight patients eventually improved after immunotherapy. DISCUSSION: PP during nasal expiration may be a cause of dyspnea in MG patients, along with respiratory muscle impairment, lung disease, and vocal cord paralysis. Laryngoscopy in the supine position is required to confirm.

Two-step nationwide epidemiological survey of myasthenia gravis in Japan 2018.

OBJECTIVE: To study the updated prevalence and clinical features of myasthenia gravis (MG) in Japan during 2017. METHODS: We sent survey sheets to the randomly selected medical departments (number = 7,545). First, we asked the number of MG patients who visited medical departments from January 1, 2017, to December 31, 2017. Then, we sent the second survey sheet to the medical departments that answered the first survey to obtain the clinical information of patients who received MG diagnosis between January 1, 2015, and December 31, 2017. RESULTS: The received answer to the first survey were 2,708 (recovery rate: 35.9%). After all, the prevalence of the 100,000 population was estimated as 23.1 (95%CI: 20.5-25.6). As a result of the second survey, we obtained 1,464 case records. After checking the duplications and lacking data, we utilized 1,195 data for further analysis. The median [interquartile range (IQR)] from the onset age of total patients was 59 (43-70) years old. The male-female ratio was 1: 1.15. The onset age [median (IQR)] for female patients was 58 (40-72) years old, and that for male patients was 60 (49-69) years old (Wilcoxon-Mann-Whitney test, p = 0.0299). We divided patients into four categories: 1) anti-acetylcholine receptor antibody (AChRAb) (+) thymoma (Tm) (-), 2) AChRAb(+)Tm(+), 3) anti-muscle-specific kinase antibody (MuSKAb) (+), and AChRAb(-)MuSKAb(-) (double negative; DN). The onset age [median (IQR)] of AChRAb(+)Tm(-) was 64 (48-73) years old, and AChRb(+)Tm(+) was 55 (45-66), MuSKAb(+) was 49 (36-64), DN was 47 (35-60) year old. The multivariate logistic regression analysis using sex, initial symptoms, repetitive nerve stimulation test (RNST), and edrophonium test revealed that sex, ocular symptoms, bulbar symptoms, and RNST were factors to distinguish each category. The myasthenia gravis activities of daily living profile at the severest state were significantly higher in MuSKAb(+). MuSKAb(+) frequently received prednisolone, tacrolimus plasmapheresis, and intravenous immunoglobulin; however, they received less acetylcholine esterase inhibitor. 99.2% of AChRAb(+)Tm(+) and 15.4% of AChRAb(+)Tm(-) received thymectomy. MuSKAb(+) did not receive thymectomy, and only 5.7% of DN received thymectomy. The prognosis was favorable in all categories. CONCLUSION: Our result revealed that the prevalence of Japanese MG doubled from the previous study using the same survey method in 2006. We also found that the onset age shifted to the elderly, and the male-female ratio reached almost even. Classification in four categories; AChRAb(+)Tm(-), AChRAb(+)Tm(+), MuSKAb(+), and DN, well describe the specific clinical features of each category and differences in therapeutic approaches.

[Immune checkpoint inhibitor-induced anti-striational antibodies in myasthenia gravis and myositis: a case report].

A 78-year-old man was treated with ipilimumab and nivolumab for advanced renal cell carcinoma with liver and lymph node metastasis. He developed diplopia, ptosis, dysphagia, and weakness of the limbs and neck, 1 month after treatment. Serum creatine kinase (CK) levels were elevated, and neck MRI revealed inflammation of the deep trunk muscles. Although anti-acetylcholine receptor antibody was negative, the edrophonium test was positive. Anti-striational antibodies such as the anti-titin and the anti-muscular voltage-gated potassium channel (Kv 1.4) antibodies (which serve as biomarkers of immune checkpoint inhibitors associated with myasthenia gravis and myositis) were positive (anti-titin antibody titer 11.51, normal <1 index; anti-Kv 1.4 antibody titer 15.13, normal <1 index). Intravenous methylprednisolone pulse therapy (1,000 mg/day for 3 days), plasmapheresis, and oral prednisolone (PSL) (20 mg/day) administration improved the patient's neurological function and normalized the serum CK levels. The PSL dosage was tapered without any worsening of clinical signs. The antibody titers decreased but remained positive (anti-titin antibody 5.00, anti-Kv 1.4 antibody 3.83) one year after the initial evaluation. Therefore, low-dose PSL (5 mg/day) administration was continued, and the patient was in remission.

The history of acetylcholinesterase inhibitors in the treatment of myasthenia gravis.

The beneficial effects of acetylcholinesterase inhibitors for the treatment of myasthenia gravis (MG) was a major discovery that came about through one young physician putting together a string of previous observations. To understand how this discovery came to light, we must first go back to earlier times when men hunted by bow-and-arrow to capture their prey. The substance used to poison the prey was eventually was identified as curare. Centuries later, a connection was made between the physiological effects of curare and a disease entity with no known pathological mechanism or treatment, myasthenia gravis. In 1935, house officer Dr. Mary Walker was the first physician to try physostigmine in the treatment of MG, which had previously been used to treat curare poisoning. What she saw was a dramatic improvement in the symptoms experienced in patients with MG, and thus became the first documented case of use of physostigmine, an acetylcholinesterase inhibitor, in the treatment of MG. This article is a summary of the history of the use of acetylcholinesterase inhibitors in the treatment of myasthenia gravis. This article is part of the special issue entitled 'Acetylcholinesterase Inhibitors: From Bench to Bedside to Battlefield'.

Idiopathic Orbital Inflammation Appearing on the Affected Side of Preceding Myasthenia Gravis.

The patient was a 70-year-old man with idiopathic orbital inflammation (IOI) that appeared on the severely affected side of preceding myasthenia gravis (MG). The patient was diagnosed with MG 5 years prior to the onset of IOI. When IOI was diagnosed, an edrophonium test was negative. IOI was considered because he complained of left orbital pain, eyelid swelling, and cerebral MRI exhibited the enhanced lesions along the left orbital periosteum. A biopsy specimen revealed pathological findings compatible with IOI. The administration of corticosteroids was effective for improving the ocular symptoms. IOI should be considered when ocular symptoms deteriorated with soft tissue swelling/pain in MG patients.

The mechanism and benefit of human butyrylcholinesterase activation by what would otherwise be inhibitors.

Activation of human butyrylcholinesterase by small quaternary ammonium ions is known. Here, additional ligands in this series are presented: edrophonium and choline, and the reactivator pyridine-2-aldoxime methochloride. Kinetic analysis of the progress curves with these compounds indicates the mechanism of enhanced deacylation by the ligand bound to the catalytic anionic site (Trp82) at the base of the active site. The larger, bis-quaternary ligands examined, as propidium, hexamethonium, decamethonium, and bis-thiocholine, show only competitive inhibition of butyrylcholinesterase, by preventing substrate approach. This hypothesis of enhanced deacylation was tested for reactivation of methanesulfonylfluoride-inactivated butyrylcholinesterase, a complex analogous to organophosphate-aged cholinesterases. The combination of substrate/products and pyridine-2-aldoxime methochloride improved butyrylcholinesterase activity over 2 h of continuous measurements, before which time substrate depletion prevailed. Similar reactivation of Torpedo californica acetylcholinesterase was unsuccessful, but both of these cholinesterases regain some activity if they have been inhibited and aged for days by diisopropylfluorophosphate.

[A case of Miller Fisher syndrome with a false-positive edrophonium test].

A 69-year-old woman presented with acute bilateral ptosis, ophthalmoplegia, ataxia, and hyporeflexia in the extremities following an antecedent upper respiratory infection. We suspected that she had Miller Fisher syndrome (MFS) and performed an edrophonium test (ET) to rule out myasthenia gravis (MG). Edrophonium chloride improved the patient's bilateral ptosis, but not her ophthalmoplegia. Given the absence of the waning phenomenon on electrophysiological examination, the anti-acetylcholine receptor antibody, and a diurnal variation of symptoms, we concluded that the ET result was a false-positive. A diagnosis of MFS was confirmed by the presence of a positive anti-GQ1b antibody. To our knowledge, this is the first case report of MFS with a false-positive ET.

Reversal of mivacurium-induced neuromuscular blockade with a cholinesterase inhibitor: A systematic review.

BACKGROUND: Mivacurium is a short-acting non-depolarizing muscle relaxant, which is hydrolyzed by butyrylcholinesterase. The neuromuscular block (NMB) can be antagonized with cholinesterase inhibitors (CHEI), but the short duration of action of mivacurium questions the need. This systematic review evaluated if the use of CHEIs (neostigmine, pyridostigmine or edrophonium) facilitates reversal of mivacurium-induced NMB. METHOD: Randomized controlled trials and crossover-studies comparing spontaneous recovery with CHEI reversal in patients with mivacurium-induced NMB, assessed with quantitative neuromuscular monitoring, were included. Mean time from injection of the CHEI or allowing of spontaneous recovery to an endpoint representing full recovery was used as outcome. First response to train-of-four nerve stimulation (T1 ) described the level of NMB for administration of the CHEI. Moderate NMB refers to T1  ≥ 5% and deeper NMB refers to T1  < 5%. Systematic critical appraisal was performed using the Scottish Intercollegiate Guidelines Network guidelines. Overall quality assessment was done using the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS: Sixteen studies with data from 546 patients were included. Low quality of evidence was found that neostigmine and edrophonium administered at moderate NMB accelerated recovery with up to approximately 5.5-6.5 and 6.5-9.0 minutes, respectively. At deeper NMB only edrophonium accelerated recovery. The effect of neostigmine was not clarified at deeper mivacurium-induced NMB. No studies with reversal by pyridostigmine were identified. CONCLUSION: Low quality of evidence supports that neostigmine and edrophonium accelerate the recovery of mivacurium-induced NMB with 5-6.5 and 6-9.0 minutes respectively, when administered at moderate NMB. At deeper NMB only edrophonium accelerated the recovery.

Two Cases of Myasthenia Gravis Showing Fatigibility Presenting with Decreased Gain of Smooth Pursuit / 대한평형의학회지

Myasthenia gravis (MG) is an autoimmune disease caused by autoantibodies to the acetylcholine receptors of the neuromuscular junction characterized by weakness and abnormal fatigability of the muscles. Therefore, the diagnosis of MG depends on the recognition of this distinctive pattern of fatigable weakness. Previous studies presented the diagnostic efficacy of saccadic eye movements in patients with ocular MG. We here in report 2 patients of ocular MG showing the fatigue effects during repetitive sustained smooth pursuit, and the effects of the administration of edrophonium on myasthenic smooth pursuit. Changes in smooth pursuits reflecting peripheral and secondary central mechanisms were demonstrated.

Pharmacological Modulation of Right Ventricular Endocardial-Epicardial Gradients in Brugada Syndrome.

Background We explored the hypothesis that increased cholinergic tone exerts its proarrhythmic effects in Brugada syndrome (BrS) through increasing dispersion of transmural repolarization in patients with spontaneous and drug-induced BrS. Methods BrS and supraventricular tachycardia patients were studied after deploying an Ensite Array in the right ventricular outflow tract and a Cardima catheter in the great cardiac vein to record endo and epicardial signals, respectively. S1-S2 restitution curves from the right ventricular apex were conducted at baseline and after edrophonium challenge to promote increased cholinergic tone. The local unipolar electrograms were then analyzed to study transmural conduction and repolarization dynamics. Results The study included 8 BrS patients (5 men:3 women; mean age, 56 years) and 8 controls patients with supraventricular tachycardia (5 men:3 women; mean age, 48 years). Electrophysiological studies in controls demonstrated shorter endocardial than epicardial right ventricular activation times (mean difference: 26 ms; P<0.001). In contrast, patients with BrS showed longer endocardial than epicardial activation time (mean difference: -15 ms; P=0.001). BrS hearts, compared with controls, showed significantly larger transmural gradients in their activation recovery intervals (mean intervals, 20.5 versus 3.5 ms; P<0.01), with longer endocardial than epicardial activation recovery intervals. Edrophonium challenge increased such gradients in both controls (to a mean of 16 ms [ P<0.001]) and BrS (to 29.7 ms; P<0.001). However, these were attributable to epicardial and endocardial activation recovery interval prolongations in control and BrS hearts, respectively. Dynamic changes in repolarization gradients were also observed across the BrS right ventricular wall in BrS. Conclusions Differential contributions of conduction and repolarization were identified in BrS which critically modulated transmural dispersion of repolarization with significant cholinergic effects only identified in the patients with BrS. This has important implications for explaining the proarrhythmic effects of increased vagal tone in BrS, as well as evaluating autonomic modulation and epicardial ablation as therapeutic strategies.

Effects of two levels of partial neuromuscular block with atracurium on the ventilatory response to hypercapnia in anesthetized Beagles.

OBJECTIVE To evaluate effects of 2 levels of partial neuromuscular block on the ventilatory response to a hypercapnic challenge in anesthetized dogs and to evaluate effects of edrophonium for reversing partial neuromuscular block. ANIMALS 6 healthy adult Beagles. PROCEDURES Each dog was anesthetized twice with propofol and dexmedetomidine. End-tidal partial pressure of CO2 (Petco2), tidal volume (Vt), and peak inspiratory flow (PIF) were measured during breathing at rest. Maximal Vt and PIF (VtMAX and PIFMAX, respectively) in response to a hypercapnic challenge consisting of 10% CO2 inhaled for 1 minute were measured. Variables were measured before administration of atracurium (baseline), during moderate (train-of-four [TOF] ratio, 0.3 to 0.5) and mild (TOF ratio, 0.6 to 0.8) atracurium-induced neuromuscular block, and after neuromuscular block recovery (TOF ratio, ≥ 0.9) following administration of edrophonium or saline (0.9% NaCl) solution. Dogs for which any variable returned to < 80% of the baseline value were identified. RESULTS Partial neuromuscular block increased Petco2; it impaired Vt at rest and VtMAX but not PIF at rest and PIFMAX. All variables except Petco2 returned to baseline values when the TOF returned to ≥ 0.9. After recovery from neuromuscular block, significantly more dogs had a VtMAX < 80% of the baseline value when edrophonium was not administered. CONCLUSIONS AND CLINICAL RELEVANCE Partial neuromuscular block in anesthetized Beagles decreased spontaneous ventilation at rest and impaired the response to a hypercapnic challenge. Response to hypercapnic challenge might remain partially impaired after recovery of the TOF ratio to ≥ 0.9.

Reliability and main findings of the flexible endoscopic evaluation of swallowing-Tensilon test in patients with myasthenia gravis and dysphagia.

BACKGROUND AND PURPOSE: Diagnosis of pharyngeal dysphagia caused by myasthenia gravis (MG) based on clinical examination alone is often challenging. Flexible endoscopic evaluation of swallowing (FEES) combined with Tensilon (edrophonium) application, referred to as the FEES-Tensilon test, was developed to improve diagnostic accuracy and to detect the main symptoms of pharyngeal dysphagia in MG. Here we investigated inter- and intra-rater reliability of the FEES-Tensilon test and analyzed the main endoscopic findings. METHODS: Four experienced raters reviewed a total of 20 FEES-Tensilon test videos in randomized order. Residue severity was graded at four different pharyngeal spaces before and after Tensilon administration. All interpretations were performed twice per rater, 4 weeks apart (a total of 160 scorings). Intra-rater test-retest reliability and inter-rater reliability levels were calculated. RESULTS: The most frequent FEES findings in patients with MG before Tensilon application were prominent residues of semi-solids spread all over the hypopharynx in varying locations. The reliability level of the interpretation of the FEES-Tensilon test was excellent regardless of the rater's profession or years of experience with FEES. All four raters showed high inter- and intra-reliability levels in interpreting the FEES-Tensilon test based on residue clearance (kappa = 0.922, 0.981). The degree of residue normalization in the vallecular space after Tensilon application showed the highest inter- and intra-rater reliability level (kappa = 0.863, 0.957) followed by the epiglottis (kappa = 0.813, 0.946) and pyriform sinuses (kappa = 0.836, 0.929). CONCLUSION: Interpretation of the FEES-Tensilon test based on residue severity and degree of Tensilon clearance, especially in the vallecular space, is consistent and reliable.

Combination of human acetylcholinesterase and serum albumin sensing surfaces as highly informative analytical tool for inhibitor screening.

In the continuous research for potential drug lead candidates, the availability of highly informative screening methodologies may constitute a decisive element in the selection of best-in-class compounds. In the present study, a surface plasmon resonance (SPR)-based assay was developed and employed to investigate interactions between human recombinant AChE (hAChE) and four known ligands: galantamine, tacrine, donepezil and edrophonium. To this aim, a sensor chip was functionalized with hAChE using mild immobilization conditions to best preserve enzyme integrity. Binding affinities and, for the first time, kinetic rate constants for all drug-hAChE complexes formation/disruption were determined. Inhibitors were classified in two groups: slow-reversible and fast-reversible binders according to respective target residence time. Combining data obtained on drug-target residence time with data obtained on serum albumin binding levels, a good correlation with potency, plasma protein binding in vivo, and administration regimen was found. The outcomes of this work demonstrated that the developed SPR-based assay is suitable for the screening, the binding affinity ranking and the kinetic evaluation of hAChE inhibitors. The method proposed ensures a simpler and cost-effective assay to quantify kinetic rate constants for inhibitor-hAChE interaction as compared with other proposed and published methods. Eventually, the determination of residence time in combination with preliminary ADME studies might constitute a better tool to predict in vivo behaviour, a key information for the research of new potential drug candidates.

Efficacy of Gaze Photographs in Diagnosing Ocular Myasthenia Gravis

BACKGROUND AND PURPOSE: The various tests that are routinely used to diagnose generalized myasthenia gravis, such as the edrophonium test, serum anti-acetylcholine-receptor antibodies (AChR-Ab), and repetitive nerve stimulation (RNS) tests, have lower diagnostic sensitivity in ocular myasthenia gravis (OMG). Diagnosing OMG becomes even more difficult when the clinical symptoms are subtle. There is no gold-standard diagnostic test available for OMG patients, and so this study compared the diagnostic sensitivity of gaze photographs with conventional tests in OMG. METHODS: Records of gaze photographs were available for 25 of 31 consecutive patients diagnosed with OMG. Each patient underwent a neuro-ophthalmologic examination, serum AChR-Ab, RNS, edrophonium test, ice tests, and the acquisition of gaze photographs. The margin reflex distance 1 (MRD1) was measured on each of the gaze photographs, with MRD1 < 2 mm or an interlid MRD1 difference of ≥2 mm on any of the gaze photographs defined as a positive sign of OMG. The diagnostic sensitivities of the tests were assessed. RESULTS: The mean age at onset was 38.5 years (range, 2–76 years), and 13 patients (52%) were men. The diagnostic sensitivities of the RNS test, AChR-Ab test, gaze photographs, and ice test were 56%, 64%, 80%, and 73%, respectively. CONCLUSIONS: The diagnostic sensitivity was higher for gaze photographs than for the other tests applied to OMG patients.

Effects of neostigmine or edrophonium on force of contraction when administered at a train-of-four ratio of 0.9 in anesthetized dogs.

OBJECTIVE: Anticholinesterase drugs may produce paradoxical neuromuscular block when administered at shallow levels of neuromuscular block. The objective of this study was to evaluate the effects of neostigmine and edrophonium when administered at near-complete reversal from nondepolarizing block in anesthetized dogs. STUDY DESIGN: Incomplete crossover, randomized, blinded experimental study. ANIMALS: A total of 12 Beagle dogs. METHODS: Each dog was anesthetized twice with propofol and maintained with isoflurane and dexmedetomidine. Intravenous (IV) vecuronium (0.1 mg kg-1) was administered. When the mechanographic train-of-four (TOF) ratio had spontaneously recovered to ≥0.9, either neostigmine (0.04 mg kg-1) or edrophonium (0.5 mg kg-1) was administered IV, preceeded by atropine. Changes in twitch height or TOF ratio were measured for the next 10 minutes. Recurarization was considered to be present if values decreased by ≥10%. RESULTS: Data from four dogs in each treatment were excluded from analysis, resulting in data from five dogs administered both treatments, three dogs administered neostigmine and three dogs administered edrophonium. There was no difference between groups for age, weight, T1 and T4 twitch heights or TOF ratio values, before or after anticholinesterase administration. The TOF ratio decreased by 17% and 18% in two of the eight dogs administered neostigmine, resulting from a larger increase in T1 relative to T4. No reductions in individual twitch amplitudes were recorded in those dogs. When edrophonium was used, no cases of recurarization were observed. CONCLUSIONS AND CLINICAL RELEVANCE: The results support use of edrophonium for reversal of shallow neuromuscular block. The decreases in TOF ratio recorded after neostigmine does not necessarily indicate muscular weakness. Although the clinical implications are uncertain, the results suggest that, at these doses, edrophonium may be preferable to neostigmine for reversal of shallow neuromuscular block in dogs.

Evaluation of the Edrophonium Challenge Test for Cervical Dystonia.

Objective To examine whether or not an edrophonium challenge test is useful for diagnosing cervical dystonia. Patients We evaluated 10 patients with cervical dystonia and 10 with hemifacial spasms (disease controls). We administered edrophonium and saline in this double-blinded study. Before and after the injection, we recorded the participants' clinical signs using a video camera to assess the objective symptoms every two minutes. Ten minutes after the saline and edrophonium injections, participants evaluated their subjective clinical signs using a visual analog scale. The objective signs on the video recordings were scored by specialists who were blinded to the treatment. The mean visual analog scale scores were compared using the Wilcoxon rank-sum test for paired continuous variables. Results The clinical signs of participants with cervical dystonia were amplified by edrophonium. In contrast, the clinical signs in participants with hemifacial spasms were not affected by the edrophonium challenge test. Conclusion The edrophonium challenge test may be useful for diagnosing cervical dystonia.

Detectable voice change with the edrophonium test in laryngeal myasthenia gravis.

A case of laryngeal myasthenia gravis in a 65-year-old woman presenting with hoarseness as the sole symptom is reported. Voice spectrography was performed before and after injection of intravenous edrophonium. There was a marked improvement in the patient's voice after the administration of edrophonium, which was confirmed by the changes seen on the sound spectrogram. This was the only objective indication of a diagnosis of myasthenia gravis. No thymoma was seen on chest X-ray and the patient was negative for anti-acetylcholine receptor antibodies. Treatment for laryngeal myasthenia gravis was initiated and the patient's vocal problems resolved. This case emphasizes the need to consider systemic diseases in the differential diagnosis of hoarseness and demonstrates the need for careful follow-up in such patients.

Bites by the Monocled Cobra, Naja kaouthia, in Chittagong Division, Bangladesh: Epidemiology, Clinical Features of Envenoming and Management of 70 Identified Cases.

AbstractWe describe 70 cases of monocled cobra (Naja kaouthia) bite admitted to Chittagong Medical College Hospital, Bangladesh. The biting snakes were identified by examining the dead snake and/or detecting N. kaouthia venom antigens in patients' serum. Bites were most common in the early morning and evening during the monsoon (May-July). Ligatures were routinely applied to the bitten limb before admission. Thirty-seven patients consulted traditional healers, most of whom made incisions around the bite site. Fifty-eight patients experienced severe neurotoxicity and most suffered swelling and pain of the bitten limb. The use of an Indian polyvalent antivenom in patients exhibiting severe neurotoxicity resulted in clinical improvement but most patients experienced moderate-to-severe adverse reactions. Antivenom did not influence local blistering and necrosis appearing in 19 patients; 12 required debridement. Edrophonium significantly improved the ability of patients to open the eyes, endurance of upward gaze, and peak expiratory flow rate suggesting that a longer-acting anticholinesterase drug (neostigmine) could be recommended for first aid. The study suggested that regionally appropriate antivenom should be raised against the venoms of the major envenoming species of Bangladesh and highlighted the need to improve the training of staff of local medical centers and to invest in the basic health infrastructure in rural communities.

Bulbar Myasthenia Gravis Superimposed in a Medullary Infarction Diagnosed by a Fiberoptic Endoscopic Evaluation of Swallowing With Simultaneous Tensilon Application

In the elderly, myasthenia gravis (MG) can present with bulbar symptoms, which can be clinically difficult to diagnose from other neurological comorbid conditions. We describe a case of a 75-year-old man who had been previously diagnosed with dysphagia associated with medullary infarction but exhibited aggravation of the dysphagia later on due to a superimposed development of bulbar MG. After recovering from his initial swallowing difficulties, the patient suddenly developed ptosis, drooling, and generalized weakness with aggravated dysphagia. Two follow-up brain magnetic resonance imaging (MRI) scans displayed no new brain lesions. Antibodies to acetylcholine receptor and muscle-specific kinase were negative. Subsequent electrodiagnosis with repetitive nerve stimulation tests revealed unremarkable findings. A diagnosis of bulbar MG could only be established after fiberoptic endoscopic evaluation of swallowing (FEES) with simultaneous Tensilon application. After application of intravenous pyridostigmine, significant improvement in dysphagia and ptosis were observed both clinically and according to the FEES.