title: Adult-onset Pompe's disease presenting with insidious hypercapnic respiratory failure.
abstract: Orthopnoea is commonly attributed to heart failure but can be caused by diaphragm weakness, which, when severe, is often associated with hypercapnic respiratory failure. Bilateral diaphragm weakness is generally due to systemic nerve or muscle disease and usually occurs in the setting of severe generalized muscle weakness, but the diaphragm can be the initial or only muscle involved. Here, we report the case of a 39-year-old female who presented with slowly progressive orthopnoea and daytime somnolence. Pulmonary function studies and polysomnogram confirmed bilateral diaphragm weakness complicated by nocturnal hypoventilation and she was subsequently diagnosed with adult-onset Pompe's disease, a rare metabolic myopathy.
authors.affiliation: Department of Thoracic Medicine The Prince Charles Hospital Chermside Australia.
authors.forename: Cara
authors.initials: C
authors.lastname: O'Callaghan
authors.affiliation: Department of Neurology Royal Brisbane and Women's Hospital Herston Australia.
authors.forename: Robert
authors.initials: R
authors.lastname: Henderson
authors.affiliation: Department of Thoracic Medicine The Prince Charles Hospital Chermside Australia.
authors.forename: Philip
authors.initials: P
authors.lastname: Masel
authors.affiliation: Department of Thoracic Medicine The Prince Charles Hospital Chermside Australia.
authors.forename: George
authors.initials: G
authors.lastname: Tay
authors.affiliation: Department of Neurology The Prince Charles Hospital Chermside Australia.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Tsang
keywords: Hypercapnia; Pompe's disease; myopathy; orthopnoea