A case of amyloid myopathy diagnosed during the treatment of myopathy associated with anti-signal recognition particle antibodies

Nobuko Kawakami, Yusuke Katsuyama, Yuka Hagiwara, Hidefumi Yoshida, Kang Kim, Kiyoshi Harada

Research output: Contribution to journalArticlepeer-review

Abstract

A 78-year-old man presented with subacute progressive proximal weakness and dysphagia. A biopsy specimen from the left biceps femoris revealed evidence of necrotic and regenerating muscle fibers, but lymphocyte infiltration was not noted. The patient was diagnosed with necrotizing myopathy with anti-signal recognition particle (SRP) antibodies. Concomitant therapy with prednisolone and azathioprine caused the serum CK level to return to normal and it caused clinical manifestations to abate. One year later, however, muscle weakness worsened. Immunoelectrophoresis of serum revealed IgG M protein, and muscle pathology revealed amyloid deposits in numerous blood vessels and at the periphery of a few muscle fibers, and deposits stained positive for anti-λ light chain antibody. The patient was diagnosed with amyloid myopathy, and therapy for systemic amyloid light chain amyloidosis caused muscle weakness to diminish. Amyloidosis is believed to be the primary pathology in this case based on the patient's response to treatment reaction, but the significance of a case involving both amyloid myopathy and necrotizing myopathy warranted examination.

Original languageEnglish
Pages (from-to)168-173
Number of pages6
JournalClinical Neurology
Volume57
Issue number4
DOIs
Publication statusPublished - 2017

Keywords

  • Amyloidmyopathy
  • Amyloidosis
  • Anti-SRP antibody
  • IgG type
  • Necrotizing myopathy

ASJC Scopus subject areas

  • Clinical Neurology

Fingerprint Dive into the research topics of 'A case of amyloid myopathy diagnosed during the treatment of myopathy associated with anti-signal recognition particle antibodies'. Together they form a unique fingerprint.

Cite this