Muscle-Specific Tyrosine Kinase Antibody Positive Myasthenia Gravis With Peripheral Nerve Hyperexcitability

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Li Yang
2015 ◽  
Vol 72 (7) ◽  
pp. 639-641 ◽  
Author(s):  
Ana Nikolic ◽  
Dragana Lavrnic ◽  
Ivana Basta ◽  
Dimitrije Nikolic ◽  
Slobodan Apostolski

Introduction. Childhood onset myasthenia gravis associated with anti-muscle-specific tyrosine kinase antibodies is very rare and atypical in presentation. Case report. As a baby, the pre-sented patient was choking and sleeping with open eyes. She had weak cry and breathing difficulties. In childhood, there were frequent falls and fluctuating swallowing difficulties. At the age of 19 she was misdiagnosed with Miller Fisher syndrome due to the presence of diplopia, ataxia and hyporeflexia with spontaneous recovery. Repetitive nerve stimulation test was normal. Four years later, after several relapses, there was significant decrement on facial muscles. Neostigmine test was negative, provoking muscle fasciculations. Serum anti-muscle-specific tyrosine kinase antibodies were positive. With cyclosporine therapy she achieved the minimal manifestations status. Conclusion. The presented case confirms that childhood onset myasthenia gravis associated with anti-muscle-specific tyrosine kinase antibodies is often with atypical presentation and spontaneous remissions, so it could be easily misdiagnosed.


2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Birte Eikeland

Research in the last few years has indicated that most voltage-gated potassium channel- (VGKC-) complex antibodies without leucine-rich glioma-inactivated protein 1 or contactin-associated protein-like 2 antibody specificity lack pathogenic potential and are not clear markers for autoimmune inflammation. Here we report on a patient with double-negative VGKC who developed severe peripheral nerve hyperexcitability, central nervous system symptoms with agitation and insomnia, dysautonomia, and systemic symptoms with weight loss, itch, and skin lesions. The disease started acutely one month after an episode of enteroviral pericarditis and responded well to immunotherapy. The patient is presumed to have developed a postinfectious immunotherapy-responsive autoimmune disease. In the setting of anti-VGKC positivity, it seems likely that anti-VGKC contributed to the pathogenesis of the patient’s symptoms of nerve hyperexcitability and that the disease was caused by an acquired autoimmune effect on the neuronal kinetics of VGKC. It is still unknown whether or not there are unidentified extracellular molecular targets within the VGKC-complex, i.e., a novel surface antigen and a pathogenic antibody that can cause affected individuals to develop a peripheral nerve hyperexcitability syndrome. This case highlights the fact that less well-characterized autoimmune central and peripheral nervous system syndromes may have infectious triggers.


Author(s):  
Bashar Katirji

Neuromuscular disorders are often classified into four major categories: anterior horn cell disorders, peripheral neuropathies, neuromuscular junction disorders and myopathies. This chapter discusses the electrodiagnostic and clinical EMG findings in these various neuromuscular disorders. Peripheral neuropathies are subdivided into focal mononeuropathies, radiculopathies, plexopathies and generalized peripheral polyneuropathies. Focal peripheral nerve lesions and generalized peripheral polyneuropathies may be axonal or demyelinating, and manifest quite distinctly on nerve conduction studies. Neuromuscular junction disorders may be presynaptic, as seen with the Lambert-Eaton myasthenic syndrome, or postsynaptic, as seen with myasthenia gravis.


2019 ◽  
Vol 11 (1) ◽  
pp. 80-86
Author(s):  
Ezgi Bakırcıoğlu-Duman ◽  
Zeynep Acar ◽  
Gülçin Benbir ◽  
Hande Yüceer ◽  
Hürtan Acar ◽  
...  

Morvan syndrome (MoS) is typically characterized by neuromyotonia, sleep dysfunction, dysautonomia, and cognitive dysfunction. However, MoS patients with mild peripheral nerve hyperexcitability (PNH) or encephalopathy features have been described. A 46-year-old woman presented with a 2-month history of constipation, hyperhidrosis, and insomnia. Neurologic examination revealed muscle twitching and needle electromyography showed myokymic discharges in all limbs. No clinical or electrophysiological features of neuromyotonia were present. Although the patient denied any cognitive symptoms, neuropsychological assessment revealed executive dysfunction, while other cognitive domains were preserved. Cranial and spinal MRIs were unrevealing and tumor investigation proved negative. Polysomnography examination revealed total insomnia, which was partially reversed upon immune-modulatory therapy. Investigation of a broad panel of antibodies revealed serum leucine-rich glioma inactivated protein 1 and contactin-associated protein 2 antibodies. The features of this case indicate that the presentation of PNH syndromes may show significant variability and that MoS patients may not necessarily exhibit full-scale PNH and encephalopathy symptoms.


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