Exogenous lipid pneumonia: A retrospective multicentre study of 44 cases in France

Abstract

A nationwide retrospective study of exogenous lipid pneumonia (ELP) was carried out to update the data on this disease, with emphasis on thoracic computed tomography (CT) scan and bronchoalveolar lavage (BAL) findings. The inclusion criteria were: 1) presence of abnormal imaging features compatible with the diagnosis of ELP; 2) presence of intrapulmonary lipids; and 3) exogenous origin of the lipid pneumonia. Forty-four cases were included (20 males and 24 females; mean age 62 ± 11 yrs), of which four were occupational (chronic inhalation of cutting mist or oily vapour in an industrial environment). Thirty of the 40 nonoccupational cases were related to aspiration of liquid paraffin used for the treatment of constipation. A condition possibly favouring oil aspiration or inhalation was present in 34 patients (77%), most commonly gastro-oesophageal reflux (n = 20) and neurological or psychiatric illness (n = 14). Fever (39%), weight loss (34%), cough (64%), dyspnoea (50%) and crepitations (45%) were the most frequent symptoms. BAL was performed in 39 cases: 23% had a lymphocytic alveolitis; 14% neutrophilic alveolitis; and 31% a mixed alveolitis (lymphocytic and neutrophilic). Alveolar consolidations (57%), ground glass opacities (39%), and alveolar nodules (23%) were the most common radiological abnormalities. The changes were bilateral (79%), predominant in the posterior and lower zones of the lobes concerned (74%), hypodense (71%), and spared the subpleural zones (52%). In 13 cases, hypodensity was retrospectively established on CT scan by the presence of a 'positive angiogram'. This sign may be of diagnostic value when the density measurement is either not possible or not reliable. In conclusion, this study provides an update of the clinical, biological and radiological profile of exogenous lipid pneumonia and, in particular, confirms the diagnostic benefit of computed tomography scan, which revealed bilateral and hypodense changes in a large majority of cases.