대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Paraquat Poisoning

Radiologic Findings

Chest radiograph taken 7 days after the admission shows ground-glass attenuations in both upper lung zones. After seven days, the areas with ground-glass attenuations are changed into consolidations with air-bronchogram. Chest radiograph taken six months later shows the areas of consolidation transforming into irregular linear opacity.
Chest HRCT obtained 7 days after the admission shows areas of ground-glass attenuations, predominantly in the subpleural regions of the posterior and dependent portions of the lung. Seven days later, the areas of ground-glass attenuations are changed into consolidations. Associated pneumomediastinum is also seen. Six months later, the areas of consolidations retracted and changed into fibrotic linear opacity with bronchiectasis and bronchiolectasia on follow-up HRCT.

Brief Review

Paraquat (1,1’-dimethyl-4,4’-bipyridylium dichloride) is a widely used herbicide that has toxic effects on the lung, liver and kidneys. Death from paraquat poisoning was primarily caused by progressive pulmonary damage with respiratory failure (1). The toxic effects of paraquat are through to result from oxygen radicals that destroy the cell membrane (2). Organ damage by paraquat depends on the balance between oxygen radicals and tissue levels of oxygen and antioxidants. Organ-specific damage to the lung is caused by both lower concentration of the antioxidants and higher concentration of oxygen within the lung. Early pathologic finding in the lung include thickening of the alveolar walls by edema, hemorrhage, and inflammatory cells. Some of the alveoli fill with fluid and large amount of fibrin (3). Late pathologic findings include pulmonary fibrosis and microcysts (2).
According to Im et al (4), there were three patterns of pulmonary abnormalities seen on the chest radiographs: a) diffuse air-space consolidation, b) diffuse cystic and linear shadows and c) focal interstitial opacities containing small cysts. During the first 7 days after ingestion, the preponderant radiologic abnormality was diffuse consolidation. Cystic (2-9mm) and linear opacities then appeared within the consolidated lung during the next 7 days, and this pattern was the preponderant finding after 2 weeks. Beyond 1 month, a focal honeycombing of the lung was the principal abnormality. Meanwhile, according to Lee et al (5), the predominant finding within the first 7 days was areas of ground-glass attenuation. The initial areas of ground-glass attenuation changed into areas of consolidation associated with bronchiectasis and areas of irregular lines. The initial areas of consolidation became more highly attenuated with bronchiectasis or areas of irregular lines on follow-up CT scans.

References

1. Bismuth C, Garnier R, Band FJ, Muszynski J, Keyes C. Paraquat poisoning: an overview of the current status. Drug Saf 1990;5:243-251.
2. Thurlbeck WM, Thurlbeck SM. Pulmonary effect of paraquat poisoning. Chest 1976;69:276-280.
3. Bullivant CM. Accidental poisoning by paraquat: report of two cases in man. Br Med J 1966;1:1272-1273.
4. Im JG, Lee KS, Han MC, Kim SJ, Kim IO. Paraquat poisoning: Findings on chest radiography and CT in 42 patients. AJR 1991;157:697-701.
5. Lee SH, Lee KS, Ahn JM, Kim SH , Hong SY. Paraquat poisoning of the lung: Thin-section CT findings. Radiology 1995;195:271-274.

Keywords

Lung, Inhalation and aspiration disease, Paraquat Poisoning