BACKGROUND: Lambert-Eaton myasthenic syndrome (LEMS) is a presynaptic neuromuscular junction disorder that is most frequently associated with small-cell lung cancer (SCLC). The titers of antibodies against voltage-gated calcium channels are frequently increased in LEMS, but only rarely is titer of anti-acetylcholine-receptor-binding antibodies (AChR-abs) increased. CASE REPORT: A 57-year-old male was admitted to our hospital due to dry mouth and eyes and progressive proximal limb weakness of 2 months duration. The results of a repetitive nerve stimulation test disclosed all criteria for the electrophysiological LEMS pattern, and the patient's AChR-abs titer was 0.587 nmol/L. At a follow-up performed 5 years after successful treatment of SCLC and LEMS, his AChR-abs titer had decreased to 0.001 nmol/L. CONCLUSIONS: We suggest that this was a case of transient pseudopositivity of AChR-abs in SCLC with LEMS.
Antibodies ; Calcium Channels ; Extremities ; Eye ; Follow-Up Studies ; Humans ; Lambert-Eaton Myasthenic Syndrome ; Lung ; Lung Neoplasms ; Male ; Mouth ; Myasthenia Gravis ; Neuromuscular Junction Diseases

Repetitive nerve stimulation test (RNS) is an easy and non-invasive test which provides objective for the presence of a myasthenic neuromuscular defect and for monitoring possible improvement through various therapeutic measures, and makes the differentiation of neuromuscular junction disorders. Analysing the RNS test of 45 normal controls and 146 patients with myasthenia gravis quantitatively, the following results obtained. 1. At low rate stimulation, the decremental response upto 2 standard deviation in normal control are 7.1% in orbicularis oculi(~), 7.6% in flexor carpi ulnaris (FCU) and 5.4% in abductor digiti guinti muscle(ADQ). There are two kinds of facilitation noticed: incremental responses at repetitive low stimulation (13.3-14.9%) immediately after tetanic stimulationy and increased mean amplitudes of compound muscle action potentials after exercise(l3-17%). Four minutes after the tetanic stimulation, the decremental responses at low rate stimulation become accentuated slightly even in normal control group. 2. At low rate stimulation. There are singificant decremental decremental responses in patients with myasthenia gravis, but statistically no significant differences are seen in the quantity of decremental responses among 2, 3 and 5/sec rate of stimulation. 3. The pattern and severity of decremental responses at low rate stimulation are depending on the clinical type of generalized myasthenia gravis. There are no decremental responses in FCU or ADQ in ocular type. The decremental responses of oo are greater than that of FCU in mild generalize myasthenia, but the reverse is true in moderate generalized type. 4. Statistically significant post-tetanic facilitation and exhaustion are noticed in patients with generalized myasthenia gravis.
Action Potentials ; Humans ; Myasthenia Gravis* ; Neuromuscular Junction Diseases

Repetitive nerve stimulation test (RNS) is an easy and non-invasive test which provides objective for the presence of a myasthenic neuromuscular defect and for monitoring possible improvement through various therapeutic measures, and makes the differentiation of neuromuscular junction disorders. Analysing the RNS test of 45 normal controls and 146 patients with myasthenia gravis quantitatively, the following results obtained. 1. At low rate stimulation, the decremental response upto 2 standard deviation in normal control are 7.1% in orbicularis oculi(~), 7.6% in flexor carpi ulnaris (FCU) and 5.4% in abductor digiti guinti muscle(ADQ). There are two kinds of facilitation noticed: incremental responses at repetitive low stimulation (13.3-14.9%) immediately after tetanic stimulationy and increased mean amplitudes of compound muscle action potentials after exercise(l3-17%). Four minutes after the tetanic stimulation, the decremental responses at low rate stimulation become accentuated slightly even in normal control group. 2. At low rate stimulation. There are singificant decremental decremental responses in patients with myasthenia gravis, but statistically no significant differences are seen in the quantity of decremental responses among 2, 3 and 5/sec rate of stimulation. 3. The pattern and severity of decremental responses at low rate stimulation are depending on the clinical type of generalized myasthenia gravis. There are no decremental responses in FCU or ADQ in ocular type. The decremental responses of oo are greater than that of FCU in mild generalize myasthenia, but the reverse is true in moderate generalized type. 4. Statistically significant post-tetanic facilitation and exhaustion are noticed in patients with generalized myasthenia gravis.
Action Potentials ; Humans ; Myasthenia Gravis* ; Neuromuscular Junction Diseases

Myasthenia gravis (MG) differs from the Lambert-Eaton syndrome (LES) clinically, electrophysiologically, and therapeutically. However. There had been a few reports documenting the coexistence of MG and LES in the same patient, which is termed as "overlap myasthenic syndrome". We had studied a patient who had showed all the clinical characteristics of MG including positive response to pyridostigmin. Unlike the usual response in MG, there had been an abnormal incremental responses at post-exercise and high rate stimulation with abnormal decremental responses at low-rate stimulation in repetitive nerve stimulation test, which satisfies the diagnostic criteria of both MG as LES.
Humans ; Lambert-Eaton Myasthenic Syndrome ; Myasthenia Gravis

BACKGROUND: The repetitive nerve stimulation (RNS) test is a useful tool in the evaluation of neuromuscular transmission disorders. In our laboratory, we frequently use Oh's method, which tests 5 kinds of muscles (flexor carpi ulnaris (FCU), abductor digiti quinti (ADQ), orbicularis oculi, nasalis and trapezius) with 3 kinds of low rate stimulation (LRS) and high rate stimulation (HRS). This method has the advantage of high sensitivity, but is time consuming and painful to patients. So, we tried to reestablish the stage of RNS to overcome this problem and to create a useful test. METHODS: We analyzed RNS data from 369 patients, retrospectively. The number of patients with myasthenia gravis (MG) was 357 and the number with myasthenic syndrome was 12. We compared the sensitivity of individual muscle as well as individual stimulation rate. And we analyzed the results of MG and myasthenic syndrome to verify the usefulness of HRS. RESULTS: The sensitivity of RNS (LRS) was 69.7% in MG (generalized symptom 86.4%, only ocular symptom 40.3%). The sensitivity was higher with 3 pps and 5 pps than with 2 pps, while the exclusion of 2 pps did not affect the sensitivity. We found only 3 cases (1.0%) with post-tetanic exhaustion (PTE) in MG patients with negative results on LRS. The distributions of resting CMAP and post-exercise CMAP were different between MG and myasthenic syndrome. In most cases of myasthenic syndrome, the resting CMAP of ADQ and FCU was below 4.0 mV and post-exercise CMAP of ADQ and FCU was above 50%. CONCLUSIONS: LRS may be done with only 3 and 5 pps, and HRS of the ulnar nerve was helpful only if there was a suspicion of myasthenic syndrome (resting CMAP<4.0 mV or post-exercise CMAP>50%, in ADQ & FCU) or a borderline decremental response in LRS.
Humans ; Muscles ; Myasthenia Gravis* ; Neuromuscular Junction Diseases ; Retrospective Studies ; Ulnar Nerve

Myasthenia gravis (MG), which is the most common autoimmune neuromuscular junction disorder, is characterized by weakness of musdes and increased fatigability after repetitive use, and recovery after rest. The diagnosis is based on a detailed history, physical examination, and pharmacological, electrophysiological, and immunological testing. Stapedial reflex abnormalities are noted, so the stapedial reflex decay test (SRDT) can be attempted. There are no reports regarding the SRDT in Korea. We report a case of MG presenting hyperacusia and ptosis that was diagnosed by the SRDT. We recommend using the SRDT in the clinical diagnosis of MG.
Hyperacusis ; Immunologic Tests ; Korea ; Myasthenia Gravis ; Neuromuscular Junction Diseases ; Physical Examination ; Reflex

Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction having multigene control. Correlation with human leukocyte antigen (HLA) genotype in MG had been reported in sporadic and familial cases. We investigated HLA genotype of two myasthenic brothers, at ages 13 and 15 years old. There was no family history of myasthenia gravis. Their ages of onset were 10 and 15 years of age, respectively. Identical subtypes in HLA analyses were found, A30, A31, B13, B61, Cw3, Cw6, DRB1*04, DRB1*07, DQA1*02, DQA1*03, DQB1*03, DQB1*02 in both of them. We report two myasthenic siblings with identical HLA type that has not been reported previously.
Adolescent ; Autoimmune Diseases ; Genotype* ; Humans ; Leukocytes ; Myasthenia Gravis* ; Neuromuscular Junction ; Siblings*

Myasthenia gravis (MG) is an autoimmune disease that affects neuromuscular junctions and usually manifests with muscle weakness that exhibits diurnal variability. However, MG can present with atypical symptoms, including very rarely cases presenting with a flaccid type of dysphonia. We report the first case of spasmodic dysphonia with a final diagnosis of generalized MG, which occurred in a 32-year-old female.
Adult ; Autoimmune Diseases ; Diagnosis ; Dysphonia* ; Female ; Humans ; Muscle Weakness ; Myasthenia Gravis* ; Neuromuscular Junction ; Voice Quality

Serious complications and death may occur in patients with neuromuscular disorders after administration of muscle relaxants that include prolonged paralysis, hyperkalemia, muscle rigidy and malignant hyperthermia. Myasthenia gravis, neuromuscular junctional lestion, is a postsynaptic autoimmune disease that reduces the acetylcholine receptor population. Those with myasthenia gravis like patients with other neuromuscular disorders respond abnormally to administration of depolarizing and non-depolarizing neuromuscular blocking agents. Therefore, many anesthesiologists avoid the use of muscle relaxants in general anesthesia for these patients, but the use of volatile anesthetics, premedicants, anticholiesterases and other drugs also have drawbacks. Special precautions should be taken with patients with myasthenia gravis to avoid interaction of muscle relaxants and other drugs at the neuromuscular junction in the anesthetic management during surgery and perioperative serious complications.
Acetylcholine ; Anesthesia, General ; Anesthetics ; Autoimmune Diseases ; Humans ; Hyperkalemia ; Malignant Hyperthermia ; Myasthenia Gravis* ; Neuromuscular Blocking Agents ; Neuromuscular Junction ; Paralysis

Paraneoplastic syndrome is a rare neurologic disorder caused not by the direct invasion or metastasis of cancer, but by the remote effects of cancer. The central- and peripheral-nervous system or neuromuscular junction area were involved in this syndrome. The pathogenesis was thought as the autoimmune disease, the result of an immunologic response to cancer and to cross-react with self-cells of the nervous system or of the neuromuscular junction, causing neuronal dam-age. Specific forms of this syndrome are often associated with specific paraneoplastic autoantibodies and cancer. The onset of neurological symptoms and detection of these antibodies often precede the diagnosis of the cancer; therefore, detection of these antibodies greatly assists the diagnosis of this syndrome and prompts investigations for the underly-ing cancer. Some paraneoplastic central neurological syndromes, such as cerebellar degeneration, limbic encephalitis, and necrotizing myelitis, were not improved by putative pathogenic autoantibodies, or by immunosuppresant or tumor removal, inspite of improvement in other peripheral neurologic syndrome, Lambert-Eaton myasthenic syndrome, neu-romyotonia, and Stiff-man syndrome. A more detailed understanding of the relationship between the cancer and the neural involvement from the molecular biological standpoint may lead to rational tumor therapy and elucidation of the mechanism of neural death. Here, major clinical forms with well-known antineuronal antibodies and specific cancers are reviewed.
Antibodies ; Autoantibodies ; Autoimmune Diseases ; Diagnosis ; Lambert-Eaton Myasthenic Syndrome ; Limbic Encephalitis ; Myelitis, Transverse ; Neoplasm Metastasis ; Nervous System ; Nervous System Diseases ; Neuromuscular Junction ; Neurons ; Paraneoplastic Syndromes* ; Small Cell Lung Carcinoma ; Stiff-Person Syndrome