Two case reports: chronic obstructive pulmonary disease developed in long term survived patients after acute paraquat poisoning

Abstract

Patients with acute paraquat poisoning mostly die of respiratory failure, and the surviving ones may live with pulmonary fibrosis, but the long-term changes in lung function are still un-clear. Two patients with acute paraquat poisoning survived for more than 7 years were followed up in Northern Jiangsu People's Hospital to evaluate the imaging and spirometric changes. Eight years after poisoning, 1 patient's chest computerized tomography (CT) revealed interstitial pneumonia, chronic bronchitis, emphysema, accompanied by bronchiectasis. Spirometric test showed very severe obstructive ventilatory dysfunction [percentage of vital capacity (VC) to predicted values was 63.7%, percentage of forced expiratory volume in one second (FEV1) to predicted values was 33.2%, percentage of forced vital capacity (FVC) to predicted values was 64.7%, forced expiratory volume in one second to forced vital capacity (FEV1/FVC) was 52.5%, percentage of maximal mid-expiratory flow (MMEF) to predicted values was 9.9%, percentage of diffusion capacity for carbon monoxide in single breath (DLCO-SB) to predicted values was 49.3%]. The radiography of the other patient who survived over 7 years after poisoning also discovered chronic bronchitis, emphysema and bullae, along with pleural effusion. Spirometry identified severe mixed ventilatory dysfunction, mainly obstructive ventilatory disorder (percentage of VC to predicted values was 47.8%, percentage of FEV1 to predicted values was 35.6%, percentage of FVC to predicted values was 49.3%, FEV1/FVC was 74.1%, percentage of MMEF to predicted values was 17.1%, percentage of DLCO-SB to predicted values was 21.8%). These 2 cases indicate that acute paraquat poisoning had long-term effects on lung structure and pulmonary function, which may be manifested as chronic obstructive pulmonary disease.