Related Experiment Video
Updated: Aug 6, 2026

A Simple Approach to Induce Experimental Autoimmune Neuritis in C57BL/6 Mice for Functional and Neuropathological Assessments
Published on: November 9, 2017
Seronegative Morvan Syndrome Presenting With Agrypnia Excitata and Peripheral Nerve Hyperexcitability: A
Hatem Mousa Taha1,2, Khaled Hatem Taha1
1Faculty of Medicine and Health Sciences, An-Najah National University Nablus Palestine.
Abstract:
We report a 63-year-old Palestinian man with seronegative Morvan syndrome presenting with the complete clinical triad: continuous neuromyotonia with visible myokymia, severe insomnia consistent with agrypnia excitata phenotype (2-3 h/night; Insomnia Severity Index [ISI] 24/28, validated Arabic version), tachycardia (118 bpm), profuse diaphoresis, and 13-kg weight loss. Electromyography (EMG) demonstrated characteristic myokymic (40-150 Hz) and neuromyotonic (> 150 Hz) discharges across 12 muscles without denervation. Brain MRI, CSF analysis, and comprehensive malignancy screening were unremarkable. Validated cell-based assays confirmed seronegativity for CASPR2 and LGI1 in both serum and CSF. A phenotype-supported diagnosis was pursued integrating the clinical triad, electrophysiological confirmation, and systematic exclusion of mimics. Combined immunotherapy (intravenous methylprednisolone, prednisone taper, azathioprine) and symptomatic treatment (carbamazepine, melatonin) resulted in marked clinical improvement at 6 months: Medical Research Council (MRC) sum score 48 → 58/60, creatine kinase (CK) 928 → 185 U/L, ISI 24 → 4, and sleep restored to 7-8 h/night, with no significant adverse effects. This case illustrates a phenotype-supported diagnostic approach applicable in resource-limited settings where first-line biological therapies are unavailable.
Related Concept Videos
Myasthenia Gravis: Diagnostic Tests
The edrophonium test is a diagnostic tool for myasthenia gravis. It involves...
Multiple Sclerosis l: Introduction
Myasthenia Gravis: Overview and Treatment
These antibodies interfere with the function of the nicotinic receptors in three ways: by binding to the receptor and disrupting acetylcholine binding; by causing cross-linking of receptors which leads...
Nephrotic Syndrome I : Introduction
Nephrotic Syndrome II : Assessment and Medical Management
Myasthenia Gravis ll: Pathophysiology
