Abstract
Secondary organizing pneumonia (SOP) is a nonspecific inflammatory response towards acute lung injuries caused by various diseases. However, organizing pneumonia (OP) secondary to occupational acute nitrogen oxide poisoning has been reported rarely. We report a 49-year-old man who suffered from nitrogen oxide poisoning after inhaling mixed gas at work. After pathological examination, he was diagnosed with OP. In the absence of other underlying factors causing OP, he was diagnosed with SOP owing to acute nitrogen oxide poisoning. After systematic treatment, the patient recovered and was discharged in better health. In patients with lung injury caused by acute nitrogen oxide poisoning, physicians should be alert to the risk of patients subsequently developing SOP, and timely diagnosis and treatment are essential for complete recovery.