Abstract Details

Title More prominent fibrosis of the cricopharyngeal muscle caused upper esophageal achalasia in inclusion body myositis

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) Neuromuscular and Clinical Neurophysiology (EMG) Posters (7:00 AM-5:00 PM)

Poster/Presentation
Number 106

Objective To evaluate myopathological features of cricopharyngeal (CP) muscle of patients with inclusion body myositis (IBM) in comparison with other swallowing muscles obtained at the time of open CP myotomy.

Background Pharyngeal dysphagia with lethal choking in patients with IBM was due to insufficient opening of the upper esophagus sphincter (UES). However, the most affected swallowing muscle has not been known well. The dysphagia could be caused by dysfunction of not only CP muscle but also other swallowing muscles.

Design/Methods We used the following inclusion criteria for open CP myotomy: (1) frequent obstruction-related dysphagia; (2) presence of the CP bar on videofluoroscopy; (3) loss of >10% of pre-diagnosis weight; and (4) lack of response to intravenous immune globulin. Of 32 consecutive patients with clinicopathologically defined IBM between March 2015 and March 2020, 4 underwent CP myotomy. Two patients were pathologically evaluated using neck muscle surgical specimens.

Results All patients remained almost free of symptoms for obstruction-related dysphagia immediately after the operation. The disappearing CP bar and relaxation of the UES on videofluoroscopy showed the expected improvement. Myopathologically, more severe endomysial fibrosis was observed in the CP muscle than in the sternocleidomastoid, sternohyoid, and omohyoid muscles. All of the neck muscle specimens were consistent with IBM myopathology: endomysial infiltrates of CD8+ cytotoxic T lymphocytes, overexpressed major histocompatibility antigen type I on the sarcolemma, and aberrant aggregation in muscle fibers immunohistochemically stained with an anti-p62 antibody.

Conclusions The prominent fibrosis of the CP muscle caused functional achalasia by impairing relaxation of the UES. The patients with IBM and CP bar treated with CP myotomy to open the upper esophagus can expect to show permanent improvement in their obstruction-related dysphagia.

Authors/Disclosures
Kenichiro Taira, MD, PhD (Jikei University School of Medicine) PRESENTER	Dr. Taira has nothing to disclose.
Madoka Mori-Yoshimura, MD, PhD (National Center Hospital, National Center of Neurology and Psychiatry)	Dr. Mori-Yoshimura has nothing to disclose.
Toshiyuki Yamamoto (National Center Hospital, National Center of Neurology and Psychiatry)	Dr. Yamamoto has nothing to disclose.
	No disclosure on file
	No disclosure on file
Ichizo Nishino, MD, PhD, F�鶹��ýӳ�� (National Institute of Neuroscience, NCNP)	The institution of Dr. Nishino has received research support from AMED.
Yuji Takahashi, MD, PhD (National Center of Neurology and Psychiatry)	The institution of Dr. Takahashi has received research support from Nihon Medi-Physics Co. Limit.. The institution of Dr. Takahashi has received research support from Takeda Pharmaceutical Company Limited.

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