MG and LEMS overlap syndrome: case report with electrophysiological and immunological evidence
Introduction
Several cases showing the combined features of myasthenia gravis (MG) and Lambert-Eaton myasthenic syndrome (LEMS) have been reported (Matsumoto et al., 1999, Oh et al., 1987). These cases were characterized by the following: (1) common oculo-bulbar symptoms, (2) a good response to edrophonium, (3) areflexia, (4) the ‘LEMS triad’ in the repetitive nerve stimulation (RNS) test, and (5) absence of small-cell lung cancer (SCLC). However, the actual existence of an MG and LEMS overlap syndrome has been questioned. In 1987, we reported one case of combined MG and LEMS (Oh et al., 1987). This is a follow-up report of the same case, describing the new finding of positive voltage-gated calcium-channel antibody (VGCC-ab), the persistent LEMS pattern in the subsequent RNS tests, and additional SFEMG and acetylcholine receptor antibody (AChR-ab) findings.
Section snippets
Clinical features
A 26-year-old woman with pernicious anemia presented with ptosis, diplopia, proximal leg weakness, a positive edrophonium test, the classic MG pattern in the RNS test (normal CMAP amplitude and decremental response at the low rate of stimulation [LRS]), and a positive AChR-ab titer at the initial evaluations in July and September 1980 (Table 1). A thymectomy was performed. When symptoms returned 6 months after a brief remission, the patient had diplopia, ptosis, hip flexor weakness, and
Discussion
At the initial evaluation our patient demonstrated all the clinical, electrophysiological, and immunological criteria of MG. The only atypical finding was areflexia, which was thought to be due to pernicious anemia. Later studies showed that this patient had the clinical, electrophysiological, and immunological criteria of LEMS. Atypical features for LEMS were oculo-bulbar palsy, a good response to edrophonium and frequent low positive AChR-ab titers.
Twenty one cases showing combined MG and
References (13)
- et al.
Incidence of serum anti-P/O-type and anti-N type calcium channel autoantibodies in the Lambert-Eaton myasthenic syndrome
Journal of the Neurological Sciences
(1997) - et al.
Specificity of calcium channel autoantibodies in Lambert-Eaton myasthenic syndrome
Lancet
(1989) - et al.
Lambert-Eaton myasthenic syndrome with ophthalmoparesis and pseudoblepharospasm
Muscle & Nerve
(1999) - et al.
Acetylcholine receptor antibodies in the Lambert-Eaton myasthenic syndrome
Neurology
(1998) Serologic profile of myasthenia gravis and distinction from the Lambert-Eaton syndrome
Neurology
(1997)- et al.
Calcium-channel antibodies in Lambert-Eaton myasthenic syndrome and other paraneoplastic syndromes
N Engl J Med
(1995)
Cited by (36)
3,4-Diaminopyridine for the treatment of myasthenia gravis with electrophysiological patterns of Lambert-Eaton myasthenic syndrome
2018, Journal of Clinical NeuroscienceStimulated single-fiber electromyography (sSFEMG) in Lambert-Eaton syndrome
2018, Clinical Neurophysiology PracticeCitation Excerpt :The Lambert-Eaton myasthenic syndrome (LEMS) is a rare autoimmune disease of the neuromuscular transmission involving the presynaptic voltage-gated calcium channels (VGCCs) (Schoser et al., 2017). In most cases (60%), LEMS represents a paraneoplastic syndrome associated with small cell lung cancer, in the remaining an idiopathic, autoimmune disease, with frequent overlap with other dysimmune syndromes, including myasthenia gravis (MG) (Oh and Sher, 2005). The typical clinical triad in LEMS consists of weakness (predominantly affecting proximal muscles), autonomic dysfunctions (including xerostomia, pupillomotor dysfunction, constipation, impaired sweating) and hypo/areflexia (Kesner et al., 2018).
Myasthenia gravis with presynaptic neurophysiological signs: Two case reports and literature review
2015, Neuromuscular DisordersElectrophysiologic Study of Disorders of Neuromuscular Transmission
2012, Aminoff's Electrodiagnosis in Clinical NeurologyDermatomyositis and concomitant overlap myasthenic syndrome: A rare presentation
2011, Journal of the American Academy of DermatologyParaneoplastic syndromes: An approach to diagnosis and treatment
2010, Mayo Clinic ProceedingsCitation Excerpt :Overrepresented cancers tend to produce neuroendocrine proteins (eg, small cell lung cancer and neuroblastoma), contain neuronal components (eg, teratomas), involve immunoregulatory organs (eg, thymomas), or affect immunoglobulin production (eg, lymphoma and myeloma).30 The clinical features, associated malignancies, diagnostic studies, and treatment options of PNS are listed in Table 2.27–79 Depending on the affected nervous system compartment, PNS symptoms may include cognitive and personality changes, ataxia, cranial nerve deficits, weakness, or numbness.