吸困难病因广泛，从轻度的、自限性疾病到危及生命的疾病均可引起呼吸困难。最常见病因为心血管、肺部和神经肌肉系统疾病。呼吸困难可为急性（例如，充血性心力衰竭急性加重、急性肺栓塞、急性心瓣膜关闭不全）、亚急性（例如，哮喘加重、慢性阻塞性肺疾病 [COPD] 加重）或慢性（例如，稳定型 COPD、稳定型间质性肺疾病）。
Tomasz J. Kuzniar, MD, PhD
Clinical Assistant Professor of Medicine
University of Chicago
Division of Pulmonary and Critical Care Medicine
NorthShore University HealthSystem
TJK is chair of the Education Committee of the American Academy of Sleep Medicine (AASM) and oversees the development of several educational products for the AASM. TJK is co-author of, and receives royalties from, two topics on sleep apnoea for UpToDate.
Dr Tomasz J. Kuzniar would like to gratefully acknowledge Dr Kamilla Kasibowska-Kuzniar and Dr Kaiser G. Lim, previous contributors to this monograph.
KK-K and KGL declare that they have no competing interests.
Nicholas Maskell, MD
Senior Lecturer and Consultant Physician
North Bristol Lung Centre
NM declares that he has no competing interests.
Najib Rahman, BM, BCh, MA (Oxon), MRCP (UK)
MRC Training Fellow and Specialist Registrar, Respiratory Medicine
Oxford Centre for Respiratory Medicine
NR declares that he has no competing interests.
Jonathan P. Parsons, MD
Division of Pulmonary, Allergy, Critical Care and Sleep Medicine
Ohio State University Medical Center
JPP declares that he has no competing interests.