A 52-year-old man presented with sudden onset of acral paresthesia and imbalance. The patient did not have any recent illness, sick contacts, or travel abroad. He denied weakness, pain, bowel or bladder incontinence, dysphagia, dysarthria, or shortness of breath. On neurologic examination, 1 month into his symptoms, he had reduced muscle strength in his finger spread, extension, and flexion on both sides graded on Medical Research Council scale 4−/5 and in toe extensors −4/−4 and toe flexors −4/4. The rest of his muscle strength was normal. Reflexes were absent throughout. He had reduced sensation to all modalities in a length-dependent pattern up to his midshin and wrists on both sides. He was severely unsteady when walking and he could not tandem. Romberg was positive. The rest of his neurologic examination was normal apart from high arches and hammertoes. The patient had a family history of Charcot-Marie-Tooth disease type 1A (CMT1A) (PMP22 duplication) and was himself tested, although asymptomatic, and was also found to be carrying the mutation.

Muscle & NerveVolume 48, Issue 2 p. 306-307 Letter to the Editor A patient with mutation in the SCN4A p.M1592v presenting with fixed weakness, rhabdomyolysis, and episodic worsening of weakness Eric Lee DO, Eric Lee DO Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North CarolinaSearch for more papers by this authorNizar Chahin MD, Nizar Chahin MD Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North CarolinaSearch for more papers by this author Eric Lee DO, Eric Lee DO Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North CarolinaSearch for more papers by this authorNizar Chahin MD, Nizar Chahin MD Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, North CarolinaSearch for more papers by this author First published: 30 January 2013 https://doi.org/10.1002/mus.23803Citations: 7Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume48, Issue2August 2013Pages 306-307 RelatedInformation

Objective: To determine if a muscle biopsy is superior or adds to the clinical diagnosis of inclusion body myositis. Background Inclusion body myositis is a mixed degenerative and inflammatory disease. There is no effective treatment. The diagnosis is confirmed by muscle biopsy showing congophilic deposits and rimmed vacuoles or by electronmicroscope showing the filamentous inclusions. Design/Methods: Twenty-one patients with clinical diagnosis of inclusion body myositis underwent muscle biopsy for confirmation. All patients had proximal and distal muscle weakness with preferential involvement of finger flexors and quadriceps muscles. Muscle biopsies were performed from a moderate weak muscle and were examined for the presence of rimmed vacuoles or congophilic deposits or both. Results: There were fourteen females and seven males. Average age at presentation was 60 years (35-80). CK level was elevated in 18 patients. Mean CK elevation was 942 U/L and ranged from 72-4774. Mean disease duration before the biopsy was 6 years and ranged from 1-15 years. The muscle biopsy confirmed the diagnosis in 15 patients. Six patients (5 females and 1 male) had no rimmed vacuoles or congophilic deposits detected on their muscle biopsies, but all patients had autoaggressive endomysial inflammatory response with mononuclear cells invading none necrotic muscle fibers. Ten patients had received different types of immunotherapy, but continued to deteriorate. Conclusions: 1- None of the patients suspecting to have IBM was found to have a different diagnosis.2- The muscle biopsy did not show the characteristic features of IBM in six patients.3- These findings question whether or not the muscle biopsy is necessary or add to the clinical diagnosis of inclusion body myositis.4-The clinical diagnosis of IBM remains superior to the muscle biopsy. Disclosure: Dr. Lee has nothing to disclose. Dr. Chahin has nothing to disclose.