Teaching neuroimages: dyspnea as a presenting manifestation of amyloid myopathy

A 69-year-old man had dyspnea followed by slowly progressive proximal leg weakness over 2 years. He had macroglossia (figure 1). Creatine kinase was 1,378 U/L. A deltoid biopsy revealed myopathy, denervation atrophy, and congophilic deposits around perimysial vessels, indicating amyloid (figure 2). Further workup revealed serum monoclonal lambda protein, bone marrow amyloid, and cardiomyopathy. Amyloid myopathy, an underrecognized entity, predominantly presents with progressive proximal weakness in primary amyloidosis.(1) Dyspnea results from cardiomyopathy or respiratory muscle weakness (our patient had both). Macroglossia due to amyloid deposition is a helpful clinical clue. The patient is on chemotherapy with cyclophosphamide, dexamethasone, and bortezomib, which improves prognosis in amyloidosis.(2.)