Isaacs’ syndrome: Clinical and paraclinical perspectives in a series of cases

Payam Sarraf; Mahan Shafie; Ghasem Farahmand; Mahsa Mayeli; Mojtaba Shahbazi; Hana Magrouni; Melika Jameie; Babak Ghelichnia Emrani; Babak Ghelichnia Emrani; Maryam Rashidi-Jazani

doi:10.18502/cjn.v23i1.16428

Payam Sarraf Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Mahan Shafie Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Ghasem Farahmand Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Mahsa Mayeli Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Mojtaba Shahbazi Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Hana Magrouni Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Melika Jameie Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Babak Ghelichnia Emrani Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Babak Ghelichnia Emrani Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
Maryam Rashidi-Jazani Iranian Center of Neurological Research, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/cjn.v23i1.16428

Keywords: Isaacs’ Syndrome; Neuromyotonia; Paraneoplastic Syndromes; Neuromuscular Disorder

Abstract

Background: Isaacs’ syndrome is a form of generalized peripheral nerve hyperexcitability (PNH) causing increased and continuous muscle activity characterized by muscle twitching, stiffness, cramps, myokymia, and pseudomyotonia. Herein, we aimed to review the clinical and paraclinical aspects of Isaacs’ syndrome in a number of cases.

Methods: We reported a series of 12 patients with Isaacs’ syndrome, including their clinical features, electrophysiological findings, laboratory parameters, malignancy work-up, and therapeutic management.

Results: In all cases, clinical and electrodiagnostic assessment was suggestive of Isaacs’ syndrome. Of the 12 studied cases, 5 patients were positive for both leucine-rich glioma inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) antibodies, 5 patients were CASPR2 positive and LGI1 negative, and 1 had borderline positive titers for CASPR2 with negative LGI1 antibody. The search for underlying malignancies was inconclusive in all subjects. After symptomatic treatment, mostly with carbamazepine or gabapentin, immunotherapies with double filtration plasmapheresis or Intravenous immunoglobulin (IVIG) provided favorable outcomes. Ultimately, all subjects fully recovered after 3-6 months of follow-up and all signs and symptoms resolved.

Conclusion: Despite the rarity of the disease, our results provide valuable information for understanding the epidemiological, clinical, and paraclinical features of Isaacs’ syndrome.