A rare case of peripheral nerve hyperexcitability in childhood: Isaacs syndrome

Isaacs syndrome is a rThTare acquired neuromuscular disorder characterized by peripheral nerve hyperexcitability. Symptoms involve progressive muscle pain, stiffness, and notable continuous diffuse myokymic muscle-twitching clinically consistent with neuromyotonia. There can be associated weakness, hyporeflexia, numbness, dysesthesias, and hyperhidrosis. Isaacs syndrome generally presents between ages 25–60, more commonly in men. Etiologies include autoimmune, often paraneoplastic, syndromes, typically associated with malignant thymic carcinomas. Therapeutic management involves treating the underlining malignancy, as well as using immune-mediated therapies including corticosteroids, intravenous immunoglobulin, plasma exchange, and rituximab. The long-term prognosis for patients with Isaacs syndrome varies, generally dependent on the underlying cause. While Isaacs syndrome is a chronic condition without a cure, it is generally treatable and not fatal.

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Variants and Differential Diagnosis of Peripheral Nerve Hyperexcitability

Klinische Neurophysiologie ◽

10.1055/s-2006-939148 ◽

2006 ◽

Vol 37 (01) ◽

Author(s):

HJ Gdynia ◽

AC Ludolph ◽

AD Sperfeld

Keyword(s):

Differential Diagnosis ◽

Peripheral Nerve ◽

Peripheral Nerve Hyperexcitability

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Ultrasound-guided Percutaneous Peripheral Nerve Stimulation for the Treatment of Complex Regional Pain Syndrome Type 1 Following a Crush Injury to the Fifth Digit: A Rare Case Report

Cureus ◽

10.7759/cureus.6506 ◽

2019 ◽

Author(s):

Ashley V Fritz ◽

Guilherme Ferreira-Dos-Santos ◽

Mark Friedrich Hurdle ◽

Steven Clendenen

Keyword(s):

Case Report ◽

Peripheral Nerve ◽

Complex Regional Pain Syndrome ◽

Nerve Stimulation ◽

Rare Case ◽

Pain Syndrome ◽

Syndrome Type ◽

Ultrasound Guided ◽

Rare Case Report

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Chapter 14 Peripheral nerve hyperexcitability and the neuromuscular junction

Handbook of Clinical Neurology - Neuromuscular Junction Disorders ◽

10.1016/s0072-9752(07)01514-x ◽

2008 ◽

pp. 433-443 ◽

Cited By ~ 2

Author(s):

Steven Vernino

Keyword(s):

Neuromuscular Junction ◽

Peripheral Nerve ◽

Peripheral Nerve Hyperexcitability

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A Patient with Double-Negative VGKC, Peripheral Nerve Hyperexcitability, and Central Nervous System Symptoms: A Postinfectious Autoimmune Disease

Case Reports in Neurological Medicine ◽

10.1155/2020/3579419 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Birte Eikeland

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Autoimmune Disease ◽

Peripheral Nerve ◽

Skin Lesions ◽

Double Negative ◽

Pathogenic Potential ◽

Peripheral Nerve Hyperexcitability ◽

Systemic Symptoms ◽

Kinetics Of

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.

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Issacs' syndrome in pediatric patient and voltage-gated potassium channels antibodies

Neurology Clinical Practice ◽

10.1212/cpj.0000000000000934 ◽

2020 ◽

pp. 10.1212/CPJ.0000000000000934

Author(s):

Andreia Forno ◽

Alexandra Rodrigues ◽

Rui Vasconcellos ◽

Paulo Rego Sousa

Keyword(s):

Potassium Channels ◽

Motor Activity ◽

Peripheral Nerve ◽

Gold Standard ◽

Neuromuscular Disease ◽

Clinical Presentation ◽

Therapeutic Option ◽

Muscle Cramps ◽

Voltage Gated ◽

Isaacs Syndrome

Isaacs’ syndrome (IS), also known as acquired neuromyotonia, is a rare neuromuscular disease, manifested by involuntary continuous motor activity.1 Although there are reports in children,2,3 IS is more frequent in adults.1 The clinical presentation can include muscle cramps, fasciculations, myokymia, and pseudomyotonia. Electromyography (EMG) remains the gold standard for diagnosis.1,4 Dysfunction of peripheral nerve voltage-gated potassium channels (VGKC) appears to be related to the development of the disease.1,3,4,5 Paraneoplastic factors also play an important role in IS.5 Anticonvulsants are the first therapeutic option.1,4,5

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Therapeutic Implications of Peripheral Nerve Hyperexcitability in Muscle Cramping

Journal of Clinical Neurophysiology ◽

10.1097/wnp.0000000000000291 ◽

2016 ◽

Vol 33 (6) ◽

pp. 560-563 ◽

Cited By ~ 3

Author(s):

Rebecca L. Hurst ◽

Lisa D. Hobson-Webb

Keyword(s):

Peripheral Nerve ◽

Therapeutic Implications ◽

Peripheral Nerve Hyperexcitability

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Insomnia and Dysautonomia with Contactin-Associated Protein 2 and Leucine-Rich Glioma Inactivated Protein 1 Antibodies: A “Forme Fruste” of Morvan Syndrome?

Case Reports in Neurology ◽

10.1159/000497817 ◽

2019 ◽

Vol 11 (1) ◽

pp. 80-86

Author(s):

Ezgi Bakırcıoğlu-Duman ◽

Zeynep Acar ◽

Gülçin Benbir ◽

Hande Yüceer ◽

Hürtan Acar ◽

...

Keyword(s):

Peripheral Nerve ◽

Neuropsychological Assessment ◽

Executive Dysfunction ◽

Cognitive Symptoms ◽

Neurologic Examination ◽

Cognitive Domains ◽

Needle Electromyography ◽

Muscle Twitching ◽

Peripheral Nerve Hyperexcitability ◽

History Of

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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