Idiopathic pulmonary fibrosis (IPF) is of unknown etiology and is characterized by a poor prognosis and no effective treatment. Pulmonary fibrosis can also occur from exposure to radiation or inhalation of noxious materials such as silica, asbestos, and coal dust. Pulmonary conditions that can result in pulmonary fibrosis include pneumonia, atelectasis, alveolar cell cancer, pulmonary edema, and lung surgery or trauma. Nonpulmonary causes include neuromuscular disease such as Guillain-Barré syndrome, amyotrophic lateral sclerosis, myasthenia gravis, and muscular dystrophy. Approximately one-third of patients can trace their initial episodes of dyspnea to a viral respiratory illness. Deformities of the bones, such as ankylosing spondylitis and scoliosis, can result in pulmonary fibrosis.