Introduction: Multifocal motor neuropathy (MMN) is a rare, treatable, immune-mediated neuropathy often associated with multifocal conduction block (CB). The hallmark electrodiagnostic feature is the presence of CB occurring at non-entrapment sites. However, MMN without CB has also been described and can be diagnosed, even in the absence of CB. Therefore, it is crucial to diagnose and identify MMN cases without CB, as it is a treatable disorder. Case presentation: We present a case with progressive symptoms of asymmetric distal upper and lower extremity weakness with no sensory deficits. Intravenous immunoglobulin (IVIG) therapy was initiated, as the patient fulfilled the criteria for probable MMN, despite the absence of CB. The patient’s symptoms demonstrated a relative plateau phase in response to IVIG. Although the patient lost follow-up visits, repeated electrodiagnostic study, conducted 11 years after initial presentation, revealed new CB in nerve segments that previously did not show any evidence of CB. Conclusion: This case emphasizes the importance of early diagnosis and respectively initiating early IVIG treatment in MMN, in order to maintain the clinical function. Underdiagnosis of clinically suspected MMN, based on absence of CB, will result in denial of treatment to potential IVIG responders.
Multifocal motor neuropathy, conduction block, intravenous immunoglobulin
Said R Beydoun has received grant research support from Alexion, Argenx, Daiichi Pharma, and Pfizer. He has served as an advisory board member for Grifols, MT Pharma and Sarepta, and is a speaker for Grifols. Leila Darki has nothing to disclose in relation to this article.
Authorship: All named authors meet the International Committee of Medical Journal Editors (ICMJE) criteria for authorship of this manuscript, take responsibility for the integrity of the work as a whole, and have given final approval to the version to be published.
Compliance with Ethics: All procedures were followed in accordance with the responsible committee on human experimentation and with the Helsinki Declaration of 1975 and subsequent revisions. Written informed consent was not obtained from the patient for publication of this case report due to loss of follow-up; no identifying information or images were used in the publication of this paper.
Leila Darki, Neuromuscular Division, Keck School of Medicine, University of Southern California, 1520 San Pablo St, Suite 3000, Los Angeles, CA 90033, US. E: Leila.firstname.lastname@example.org
This article is published under the Creative Commons Attribution Noncommercial License, which
permits any non-commercial use, distribution, adaptation and reproduction provided the original author(s) and source are given appropriate credit.
Share this Article
Related Content In Neuromuscular Diseases
Foreword – touchREVIEWS in Neurology, Volume 17, Issue 1, 2021
Welcome to touchREVIEWS in Neurology, our newly-named journal, previously US Neurology. The decision to expand the scope of the journal was taken after an excellent year for touchNEUROLOGY. We feel that in an increasingly global research community, submissions were limited by an assumed primary reach to one regional audience. By taking on submissions from the […]
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and Vaccinations: Examining the Current Literature on Vaccinations and the Onset or Worsening of CIDP Symptoms
touchREVIEWS in Neurology. 2021;17(1):3-5 DOI: https://doi.org/10.17925/USN.2021.17.1.3
Chronic inflammatory demyelinating polyneuropathy (CIDP) is an acquired progressive sensorimotor neuropathy of the peripheral nerves and nerve roots that appears to be immune-mediated by both the cellular and humoral immune systems. It is caused by chronic damage to the myelin sheaths of the neurons of the peripheral nervous system. It has a variable prognosis, with […]
Erratum to: Neuropathy Associated with Hereditary Transthyretin Amyloidosis—Diagnosis and Management
touchREVIEWS in Neurology. 2020;17(1): [online only]
In the originally published article there was an error in Table 4. The efficacy of patisiran was incorrectly given as “mNIS+7: 80.9 versus 74.6 with placebo; Norfolk QOL-DN: 59.6 versuss 55.4”; this should read “mNIS+7: 34 points better than placebo; Norfolk QOL-DN: 21.1 points better than placebo”. The “Concerns” of patisiran should also read “Local […]
Journal articles and more to your inbox
Get the latest clinical insights from touchNEUROLOGYSign me up!