Diaphragm paralysis in primary systemic amyloidosis.

A patient with primary (AL) systemic amyloidosis developed mononeuropathy multiplex complicated by diaphragmatic failure. High dose melphalan and autologous stem cell transplantation did not ameliorate neuropathy or diaphragm dysfunction. Nocturnal non-invasive ventilation lowered arterial carbon dioxide levels and improved daytime dyspnea. This is the first case associating AL amyloid-induced neuropathy with diaphragm dysfunction.