Observations of the fibrosing process in paraquat lung injury by chest X-ray and CT

Abstract

A 42-year-old woman with a known history of paraquat ingestion was admitted to our hospital on the 10th day after ingestion complaining of dyspnea and general fatigue. Steroid therapy and low dose oxygen therapy were administered. She recovered and was discharged on the 190th day after paraquat ingestion. A chest X-ray film on admission disclosed a bilateral ground-glass shadow. As time passed, a reticular shadow with a loss of lung volume leaving a peripherally clear zone appeared on chest X-rays and shrank gradually toward the peri-hilar area during the course. CT of the lung clearly demonstrated progress of the pulmonary fibrosing process. In the early phase of paraquat poisoning, CT revealed diffuse high density areas dominant in the posterior part of the lungs with a subpleural intact area. The high density area was sharply demarcated from the subpleural intact area. As time passed, the high density area shrank toward the central zone, causing bullous changes in the subpleural area. The dominant fibrotic change in the intermediate and central zones seems to be one of the characteristic findings in paraquat induced pulmonary fibrosis.