Paraquat Poisoning of the Lung: HRCT Findings According to the Amount of Ingestion

Abstract

Purpose: This study was designed to investigate the pattern, distribution and extent of pulmonary abnormalities in relation to the amount of ingested paraquat as determined with the use of high resolution computed tomography (HRCT). Materials and Methods: The study included 15 patients exposed to paraquat based on a positive urine assay and the presence of pulmonary abnormalities as detected on HRCT scans. The pattern, distribution and extent of pulmonary abnormalities in relation to the amount of ingested paraquat was evaluated. Patients were classified into five groups based on the amount of paraquat that was ingested. The groups were designated as indirect exposure, minimum exposure (the patient spat out the agent after swallowing), low exposure ( 30 cc), medium exposure (31-60 cc) and high exposure (61-100 cc). Results: Abnormal lung parenchymal patterns as depicted on HRCT images consisted of ground glass opacity (n = 9), consolidation (n = 9), irregular lines (n = 9) and the presence of nodules (n = 2). The most common distribution was in the lower and subpleural lung zone with no relation to the amount of ingestion. The most common patterns were the presence of irregular lines in the indirect exposure group and ground glass opacity in the high exposure group. The mean number of involved lobes increased in relation to the amount of ingestion. Conclusion: For paraquat poisoning, the pattern and extent of pulmonary abnormalities were related to the amount of ingestion, but the distribution of pulmonary abnormalities was not related to the amount of ingestion.