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.
Autoantibodies ; Autoimmune Diseases ; Diagnosis ; Edrophonium ; Fatigue ; Humans ; Muscles ; Myasthenia Gravis ; Neuromuscular Junction ; Pursuit, Smooth ; Receptors, Cholinergic ; Saccades

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.
Age of Onset ; Antibodies ; Diagnosis ; Diagnostic Tests, Routine ; Edrophonium ; Humans ; Ice ; Male ; Myasthenia Gravis* ; Reflex

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.
Acetylcholine ; Aged ; Antibodies ; Brain ; Deglutition Disorders ; Deglutition* ; Diagnosis ; Edrophonium* ; Electrodiagnosis ; Fees and Charges ; Follow-Up Studies ; Humans ; Infarction* ; Magnetic Resonance Imaging ; Myasthenia Gravis* ; Phosphotransferases ; Pyridostigmine Bromide ; Sialorrhea ; Stroke

BACKGROUND: The coexistence of myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) is very rare and remains controversial. CASE REPORT: A 48-year-old woman initially presented with noticeable right ptosis and intermittent diplopia. She then developed fluctuating proximal limb weakness and difficulty in swallowing. The serum titer of anti-acetylcholine-receptor antibody was elevated and the edrophonium (Tensilon) test was positive. However, repetitive nerve stimulation revealed abnormalities typical of LEMS. The patient exhibited a good response to treatment with anticholinesterase inhibitors and steroids, and long-term evaluation disclosed that she presented with the clinical, electrophysiological, and immunological characteristics of both diseases. CONCLUSIONS: The reported clinical and electrophysiological features suggest that this patient was a very rare case of combined MG and LEMS.
Deglutition ; Diplopia ; Edrophonium ; Extremities ; Female ; Humans ; Lambert-Eaton Myasthenic Syndrome ; Middle Aged ; Myasthenia Gravis ; Steroids

Muscle-specific tyrosine-kinase-antibody-positive myasthenia gravis (MuSK-MG) has emerged as a distinct entity since 2001. This disease has been reported worldwide, but with varying rates among patients with generalized acetylcholine-receptor-antibody-negative MG. MuSK-MG was detected in approximately 37% of generalized acetylcholine receptor antibody-negative MG. MuSK-MG patients were predominantly female with more prominent facial and bulbar involvement and more frequent crises. Disease onset tended to be earlier. Patients tended to have a relatively poor edrophonium response but showed prominent decrement in the repetitive nerve stimulation test in the facial muscles. Patients were more likely to display poor tolerance of, or a lack of improvement with, anticholinesterase agents. Somewhat better response was observed with steroids and plasma exchange. Most were managed successfully with aggressive immunomodulatory therapies, although a higher proportion of MuSK-MG patients had a refractory course when compared with other forms of generalized MG. I present here an up-to-date overview on MuSK-MG based on our experience at the University of Alabama at Birmingham and the existing literature.
Acetylcholine ; Alabama ; Cholinesterase Inhibitors ; Edrophonium ; Facial Muscles ; Female ; Humans ; Immunomodulation ; Myasthenia Gravis ; Plasma Exchange ; Protein-Tyrosine Kinases ; Steroids ; Tyrosine

BACKGOUND: Cholinesterase inhibitors and N-methyl-D-aspartate (NMDA) antagonists reduce the mechanical allodynia in neuropathic pain models. In this study our aim was to compare the antiallodynic effects between intrathecal cholinesterase inhibitors and NMDA antagonists on two well-characterized neuropathic pain rat models. METHODS: Male Sprague Dawley rats were anesthetized and either had the left L5 and L6 spinal nerves ligated (SNL group) or Freund complete adjuvant (FCA) administrated to the sciatic nerve (FCA group) in order to cause neuropathic pain. A catheter was implanted into the intrathecal space for drug administration. After obtaining baseline values, edrophonium (3-100microgram), neostigmine (0.3-10microgram), AP-5 (0.3-3microgram) and MK-801 (1-30microgram) were administered intrathecally to each group. The allodynic left hind paw withdrawal thresholds to von Frey hairs were assessed and converted to % MPE. Antiallodynic effects on the two groups were compared by analyzing dose-response curves and ED 50 values. Motor weakness was also checked. RESULTS: Intrathecal edrophonium, neostigmine, AP-5 and MK-801 had a dose-dependent antiallodynic effect on the two neuropathic pain models. Comparing the antiallodynic effect dose response curves, intrathecal cholinesterase inhibitors had lower ED 50 with steep slopes in the SNL model, whereas intrathecal NMDA antagonists had lower ED 50 in the FCA model, but there were no statistically significant differences between the two models. CONCLUSIONS: Intrathecal cholinesterase inhibitors and NMDA antagonists have relatively better antiallodynic effects on the SNL and FCA neuropathic pain rat models, respectively.
Animals ; Catheters ; Cholinesterase Inhibitors* ; Cholinesterases* ; Dizocilpine Maleate ; Edrophonium ; Hair ; Humans ; Hyperalgesia ; Male ; Models, Animal* ; N-Methylaspartate* ; Neostigmine ; Neuralgia* ; Rats* ; Rats, Sprague-Dawley ; Sciatic Nerve ; Spinal Nerves

Myasthenia gravis is an autoimmune disorder affecting the neuromuscular junction. It may considerably affect the course of the pregnancy and cause serious compications in both the mother and the infant. Antibodies to nicotinic acetylcholine receptors are the cause of the disturbant nerve impulse transmission to muscle fibers. The clinical state at the beginning of pregnancy does not predict the occurrence of exacerbations or remissions. Each pregnancy has its effect on myasthenia gravis symptoms and does not predict the course of subsequent pregnancies. We experienced a patient received respiratory support because of poor ventilation after repeat caesarean section, but she recovered without complications soon. Two days later after operation, she complained of dysphasia, dysarthria. Then, Tensilon test and acetylcholine receptor antibody test were done. She was diagnosed as myasthenia gravis and administered pyridostigmine as therapeutic dose. We present this case with brief review of the concerned literatures.
Acetylcholine ; Action Potentials ; Antibodies ; Aphasia ; Cesarean Section ; Dysarthria ; Edrophonium ; Female ; Humans ; Infant ; Mothers ; Myasthenia Gravis* ; Neuromuscular Junction ; Pregnancy ; Pyridostigmine Bromide ; Receptors, Nicotinic ; Ventilation

PURPOSE: To compare the results of the ice test with other diagnostic tests for the diagnosis of myasthenia gravis in patients with ptosis. METHODS: The patients included in this study presented with suspicious myasthenic blepharoptosis and visited the Department of Ophthalmology, Guro Hospital, Korea University between March 2003 and February 2004 for diagnosis. All patients received "myasthenic ptosis workup" including the ice test, edrophonium test, RNS EMG, and anti-acetylcholine receptor antibody (anti-AchR) titer test. The tests were compared for specificity, sensitivity, ease of performance, economic benefits and observed complications. RESULTS: The patients included six men and nine women with an average age of 36.9+/-2.4 yrs. Positive test results were obtained as follows: Ice test 80%, edrophonium test 66.7%, RNS EMG 53.3%, and anti-AchR titer test 86.7%. Adverse effects of edrophonium test were encountered in two patients who had nausea, vomiting, and dizziness. CONCLUSIONS: The authors found that the ice test was simpler, faster, more economic, and safer than the others for diagnosing blepharoptosis caused by myasthenia gravis. Considering its relative high sensitivity and specificity, the ice test should be the first screening test given to patients with suspicious myasthenic ptosis.
Blepharoptosis ; Diagnosis* ; Diagnostic Tests, Routine ; Dizziness ; Edrophonium ; Female ; Humans ; Ice* ; Korea ; Male ; Mass Screening ; Myasthenia Gravis* ; Nausea ; Ophthalmology ; Sensitivity and Specificity ; Vomiting

PURPOSE: To compare the results of the ice test with other diagnostic tests for the diagnosis of myasthenia gravis in patients with ptosis. METHODS: The patients included in this study presented with suspicious myasthenic blepharoptosis and visited the Department of Ophthalmology, Guro Hospital, Korea University between March 2003 and February 2004 for diagnosis. All patients received "myasthenic ptosis workup" including the ice test, edrophonium test, RNS EMG, and anti-acetylcholine receptor antibody (anti-AchR) titer test. The tests were compared for specificity, sensitivity, ease of performance, economic benefits and observed complications. RESULTS: The patients included six men and nine women with an average age of 36.9+/-2.4 yrs. Positive test results were obtained as follows: Ice test 80%, edrophonium test 66.7%, RNS EMG 53.3%, and anti-AchR titer test 86.7%. Adverse effects of edrophonium test were encountered in two patients who had nausea, vomiting, and dizziness. CONCLUSIONS: The authors found that the ice test was simpler, faster, more economic, and safer than the others for diagnosing blepharoptosis caused by myasthenia gravis. Considering its relative high sensitivity and specificity, the ice test should be the first screening test given to patients with suspicious myasthenic ptosis.
Blepharoptosis ; Diagnosis* ; Diagnostic Tests, Routine ; Dizziness ; Edrophonium ; Female ; Humans ; Ice* ; Korea ; Male ; Mass Screening ; Myasthenia Gravis* ; Nausea ; Ophthalmology ; Sensitivity and Specificity ; Vomiting

BACKGROUND: We evaluated the pharmacodynamic and pharmacokinetic properties of rapacuronium, a new non-depolarizing muscle relaxant. METHODS: The EC50 and EC95 values of rapacuronium, vecuronium, and rocuronium were determined on rat hemidiaphragm, and reversal effects were determined using edrophonium or pyridostigmine. In 57 healthy adults, neuromuscular transmission was monitored at the adductor pollicis. Patients received a single dose of succinylcholine (1.0 mg/kg), rapacuronium (1.5 mg/kg), rocuronium (0.6 mg/kg), or mivacurium (0.16 mg/kg). Onset time, clinical duration, recovery index (RI), total duration (TD), train of four (TOF) ratio at over 95% recovery of control first twitch height, cardiovascular effect, and intubation scores were measured. RESULTS: By in vitro study, the EC50 and EC95 of rapacuronium were 4 to 10 fold larger than those of vecuronium and rocuronium, and by clinical study, the onset time of rapacuronium was similar to those of succinylcholine. The clinical duration of rapacuronium was not different from those of succinylcholine and mivacurium. RI and TD of rapacuronium (9.6 +/- 3.5 min and 30.9 +/- 10.7 min) were longer than those of succinylcholine (3.5 +/- 1.1 min and 18.1 +/- 4.4 min) and mivacurium (6.5 +/- 0.9 min and 23.0 +/- 4.4 min) for spontaneous recovery, but not different during reversal by pyridostigmine (5.0microgram/kg). The TOF ratio was increased after pyridostigmine than during spontaneous recovery. Intubation conditions of rapacuronium were similar to those of succinylcholine. Heart rates were significantly increased (15% of control) within 2 min, but not mean arterial pressure after rapacuronium was administration. CONCLUSIONS: Rapacuronium can be considered a valid alternative to succinylcholine and had no observed cardiovascular effect.
Adult ; Animals ; Arterial Pressure ; Edrophonium ; Heart Rate ; Humans ; Intubation ; Neuromuscular Blockade* ; Pyridostigmine Bromide ; Rats ; Succinylcholine ; Vecuronium Bromide