Showing papers by "Yu-ichi Noto published in 2014"

Contrasting echogenicity in flexor digitorum profundus–flexor carpi ulnaris: A diagnostic ultrasound pattern in sporadic inclusion body myositis

Abstract: Introduction: In this study we aimed to clarify whether muscle ultrasound (US) of the forearm can be used to differentiate between patients with sporadic inclusion body myositis (s-IBM) and those with s-IBM–mimicking diseases. Methods: We compared the echo intensity (EI) of the flexor digitorum profundus (FDP) muscle and the flexor carpi ulnaris (FCU) muscles in patients with s-IBM (n = 6), polymyositis/dermatomyositis (PM/DM; n = 6), and amyotrophic lateral sclerosis (ALS; n = 6). Results: We identified EI abnormalities in 100% of patients with s-IBM, 33% of those with PM/DM, and 33% of those with ALS. An “FDP–FCU echogenicity contrast,” a US pattern involving a higher EI in the FDP than in the FCU, was observed in all patients with s-IBM, but in none of those with PM/DM or ALS. Conclusions: FDP–FCU echogenicity contrast in muscle US is a sensitive diagnostic indicator of s-IBM. Muscle Nerve 49: 745–748, 2014

[Ultrasound diagnosis of Charcot-Marie-Tooth disease].

Abstract: Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous group of diseases with over 45 different causative gene mutations identified. Nerve conduction studies are important for the classification and diagnosis of CMT, whereas ultrasound (US) is increasingly used to assess the peripheral nerves of patients with CMT, as a complement to neurophysiological studies. Recent ultrasound assessment reports of peripheral nerves in CMT are summarized here. An ultrasound finding of CMT1A, which is the most common demyelinating subtype of CMT, is characterized by uniform enlargement of peripheral nerves and nerve roots. Patients with CMT1B (MPZ mutation) also have larger nerves than normal subjects do. Peripheral nerves of patients with CMT2, which is an axonal type of CMT, are slightly larger than those of normal subjects. Focal enlargement of nerves at entrapment sites is a characteristic US finding of hereditary neuropathy with liability to pressure palsy. US findings of CMT are thus subtype-specific. Therefore, the assessment of nerve US may become a useful supporting tool for the diagnosis of CMT subtypes.

[Normokalemic periodic paralysis lasting for two weeks: a severe form of sodium channelopathy with M1592V mutation].

Abstract: A 73-year-old man with recurrent periodic paralytic episodes lasting for two weeks each admitted to our hospital because of the leg weakness and the elevated value of serum creatine kinase. On admission, weakness in the proximal legs and mild eye lid myotonia were noted. Needle electromyography revealed abundant myotonic discharges. The prolonged exercise test showed a continuous reduction of compound muscle action potentials in the abductor digiti minimi muscle. Direct sequencing of SCN4A in the proband showed a G-to-A alteration at position 4774 that results in a change of 1592(nd) methionine to valine (M1592V). Cosegregation regarding the M1592V mutation and paralytic phenotype in this family was confirmed. Two cardinal features in this family were longer paralytic episodes compared to classical hyperkalemic/normokalemic periodic paralysis and the normal potassium value during the paralytic episodes. This study together with antecedent reports indicates that M1592V mutation shares a much greater clinical diversity ranging from congenital paramyotonia to periodic paralysis with a longer duration.