098 A case of myasthenia gravis lambert eaton overlap syndrome (MLOS) in seronegative myasthenia gravis

2018 ◽  
Vol 89 (6) ◽  
pp. A39.1-A39
Author(s):  
Sameer Saleem ◽  
Ronak Patel ◽  
Yash Gawarikar
Keyword(s):  
Myasthenia Gravis ◽  
Calcium Channel ◽  
Overlap Syndrome ◽  
Initial Examination ◽  
Blurred Vision ◽  
Voltage Dependent Calcium Channel ◽  
Seronegative Myasthenia Gravis ◽  
Voltage Dependent ◽  
Myasthenic Syndrome ◽  
Seronegative Mg

IntroductionMyasthenia gravis (MG) is an antibody-mediated autoimmune disease of neuromuscular transmission. 6 to 12 percent of MG are negative for acetyl choline receptor (AChR) and MuSK antibodies and are defined as seronegative MG. Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune condition with antibodies to presynaptic voltage-dependent calcium channelCaseA 39 year old male presented with blurred vision and right-sided ptosis. Initial examination showed a pupil-sparing left complete third nerve palsy. Demyelination and intracranial aneurysms were ruled out with gadolinium-enhanced MRI/MRA. Outpatient follow-up 2 weeks later showed new onset proximal muscle weakness of the upper limbs with fatigability and a complex ophthalmoplegia with almost complete paralysis of gaze. A repeat MRI with gadolinium and CSF analysis were normal. His AChR and MuSK antibodies were negative; however, voltage-dependent calcium channel antibodies, ANA, dsDNA, and SSA were positive. Initial nerve conduction tests were normal, but repeat NCS on two separate occasions showed decrement on repetitive stimulation in the right trapezius with no evidence of facilitation post exercise. CT chest, abdomen and pelvis was normal. He improved with pulsed steroids and was discharged on a tapering dose of oral steroids, pyridostigmine and regular IVIG infusions as a steroid-sparing agent.ConclusionLambert-Eaton myasthenic syndrome shares the same pathologic site and similar pathophysiology with MG but has a markedly different clinical and electro-physiological picture. There are reports of MG and LEMS overlap syndrome, however, they exhibit phenotypic characteristics of both LEMS and MG. Voltage-dependent calcium channel antibodies have not been described in patients with seronegative MG. Ours is potentially the first reported case of seronegative myasthenia with voltage-dependent calcium channel antibodies and only clinical and neurophysiological features of MG.

scholarly journals Clinical features of neuromuscular disorders in patients with N-type voltage-gated calcium channel antibodies

2016 ◽  
Vol 26 (4) ◽  
Author(s):  
Andreas Totzeck ◽  
Petra Mummel ◽  
Oliver Kastrup ◽  
Tim Hagenacker
Keyword(s):  
Myasthenia Gravis ◽  
Calcium Channel ◽  
Muscle Weakness ◽  
Neuromuscular Disorders ◽  
Intravenous Immunoglobulins ◽  
Voltage Gated ◽  
Dropped Head Syndrome ◽  
Seronegative Myasthenia Gravis ◽  
Myasthenic Syndrome ◽  
Voltage Gated Calcium Channel

Neuromuscular junction disorders affect the pre- or postsynaptic nerve to muscle transmission due to autoimmune antibodies. Members of the group like myasthenia gravis and Lambert-Eaton syndrome have pathophysiologically distinct characteristics. However, in practice, distinction may be difficult. We present a series of three patients with a myasthenic syndrome, dropped-head syndrome, bulbar and respiratory muscle weakness and positive testing for anti-N-type voltage-gated calcium channel antibodies. In two cases anti-acetylcholin receptor antibodies were elevated, anti-P/Q-type voltage-gated calcium channel antibodies were negative. All patients initially responded to pyridostigmine with a non-response in the course of the disease. While one patient recovered well after treatment with intravenous immunoglobulins, 3,4-diaminopyridine, steroids and later on immunosuppression with mycophenolate mofetil, a second died after restriction of treatment due to unfavorable cancer diagnosis, the third patient declined treatment. Although new antibodies causing neuromuscular disorders were discovered, clinical distinction has not yet been made. Our patients showed features of pre- and postsynaptic myasthenic syndrome as well as severe dropped-head syndrome and bulbar and axial muscle weakness, but only anti-N-type voltage-gated calcium channel antibodies were positive. When administered, one patient benefited from 3,4-diaminopyridine. We suggest that this overlap-syndrome should be considered especially in patients with assumed seronegative myasthenia gravis and lack of improvement under standard therapy.

Distribution of neurons expressing α1G subunit mRNA of T-type voltage-dependent calcium channel in adult rat central nervous system

1999 ◽  
Vol 268 (2) ◽  
pp. 77-80 ◽  
Author(s):  
Masahiko Kase ◽  
Shingo Kakimoto ◽  
Satoru Sakuma ◽  
Takeshi Houtani ◽  
Hitoshi Ohishi ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Calcium Channel ◽  
Adult Rat ◽  
Subunit Mrna ◽  
Voltage Dependent Calcium Channel ◽  
Voltage Dependent

scholarly journals Voltage-Dependent Calcium Channel CaV1.3 Subunits Regulate the Light Peak of the Electroretinogram

2007 ◽  
Vol 97 (5) ◽  
pp. 3731-3735 ◽  
Author(s):  
Jiang Wu ◽  
Alan D. Marmorstein ◽  
Jörg Striessnig ◽  
Neal S. Peachey
Keyword(s):  
Calcium Channel ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Rod Photoreceptor ◽  
Wild Type ◽  
Fast Oscillation ◽  
Light Peak ◽  
Voltage Dependent Calcium Channel ◽  
Voltage Dependent ◽  
Voltage Dependent Calcium Channels

In response to light, the mouse retinal pigment epithelium (RPE) generates a series of slow changes in potential that are referred to as the c-wave, fast oscillation (FO), and light peak (LP) of the electroretinogram (ERG). The LP is generated by a depolarization of the basolateral RPE plasma membrane by the activation of a calcium-sensitive chloride conductance. We have previously shown that the LP is reduced in both mice and rats by nimodipine, which blocks voltage-dependent calcium channels (VDCCs) and is abnormal in lethargic mice, carrying a null mutation in the calcium channel β4 subunit. To define the α1 subunit involved in this process, we examined mice lacking CaV1.3. In comparison with wild-type (WT) control littermates, LPs were reduced in CaV1.3−/− mice. This pattern matched closely with that previously noted in lethargic mice, confirming a role for VDCCs in regulating the signaling pathway that culminates in LP generation. These abnormalities do not reflect a defect in rod photoreceptor activity, which provides the input to the RPE to generate the c-wave, FO, and LP, because ERG a-waves were comparable in WT and CaV1.3−/− littermates. Our results identify CaV1.3 as the principal pore-forming subunit of VDCCs involved in stimulating the ERG LP.

Localization of voltage-dependent calcium channel subunit alpha 1A (Cav2.1) in the rat cerebellum

2010 ◽  
Vol 68 ◽  
pp. e110
Author(s):  
Dwi Wahyu Indriati ◽  
Naomi Kamasawa ◽  
Masahiko Watanabe ◽  
Ryuichi Shigemoto
Keyword(s):  
Calcium Channel ◽  
Rat Cerebellum ◽  
Voltage Dependent Calcium Channel ◽  
Voltage Dependent

scholarly journals Role of Voltage-Dependent Calcium Channel Long-Term Potentiation (LTP) and NMDA LTP in Spatial Memory

2000 ◽  
Vol 20 (24) ◽  
pp. 9272-9276 ◽  
Author(s):  
Albert M. Borroni ◽  
Harlan Fichtenholtz ◽  
Brian L. Woodside ◽  
Timothy J. Teyler
Keyword(s):  
Spatial Memory ◽  
Calcium Channel ◽  
Long Term Potentiation ◽  
Voltage Dependent Calcium Channel ◽  
Term Potentiation ◽  
Voltage Dependent
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