title: [Chronic Farmer's lung disease with emphysema].
abstract: BACKGROUND
  Farmer's lung (FL) is the most common type of hypersensitivity pneumonitis (HP), with an estimated prevalence of between 0.5 and 1.5% in dairy farmers. In chronic FL, fibrotic sequelae are widely described in the literature although our experience and occasional epidemiological studies emphasize an increased risk of developing emphysema in these patients.
  
  
  METHODS
  We report a case of FL in a 37-year-old patient with typical clinical features (exertional dyspnoea, lymphocytic alveolitis and computed tomography appearances) together with proven allergen exposure. This patient developed early pulmonary emphysema probably due to intermittent massive exposure to antigens and to bacterial and fungal micro-organisms.
  
  
  CONCLUSIONS
  The current classification of HP differentiates acute, subacute and chronic forms but does not take account of the role of the mode of exposure and the evolution of the disease. The prognosis and evolution of HP seem to be dependent on the type and pattern of exposure. A new classification with two clusters has been suggested: in type 1, massive and intermittent exposure, as in FL, may lead to emphysema with chronic airflow obstruction and, in type 2, chronic exposure to a low level, as in bird fanciers, may lead to fibrosis with a restrictive pattern.
authors.affiliation: Service de pneumologie, hôpital Jean-Minjoz, 2, boulevard Fleming, 25030 Besancon cedex, France. Electronic address: thibaud_soumagne@live.fr.
authors.forename: T
authors.initials: T
authors.lastname: Soumagne
authors.affiliation: Service d'explorations fonctionnelles de la respiration, de l'exercice et de la dyspnée, hôpital Jean-Minjoz, 2, boulevard Fleming, 25030 Besancon cedex, France.
authors.forename: B
authors.initials: B
authors.lastname: Degano
authors.affiliation: Service de pneumologie, hôpital Jean-Minjoz, 2, boulevard Fleming, 25030 Besancon cedex, France.
authors.forename: J C
authors.initials: JC
authors.lastname: Dalphin
mesh_terms: D000328:Adult; D000402:Airway Obstruction / Q000209:etiology; D000485:Allergens / Q000009:adverse effects; D000542:Alveolitis, Extrinsic Allergic / Q000145:classification / Q000209:etiology / Q000473:pathology / Q000503:physiopathology; D000821:Animal Feed / Q000009:adverse effects / Q000382:microbiology; D000818:Animals; D000942:Antigens, Bacterial / Q000009:adverse effects; D000946:Antigens, Fungal / Q000009:adverse effects; D018450:Disease Progression; D004391:Dust; D005203:Farmer's Lung / Q000150:complications* / Q000175:diagnosis; D005355:Fibrosis; D006799:Housing, Animal; D006801:Humans; D008297:Male; D016273:Occupational Exposure; D011379:Prognosis; D011656:Pulmonary Emphysema / Q000175:diagnosis / Q000209:etiology*; D012129:Respiratory Function Tests; D014691:Ventilation
chemical_list: D000485:Allergens; D000942:Antigens, Bacterial; D000946:Antigens, Fungal; D004391:Dust
keywords: Emphysema; Emphysème; Farmer's lung; Fibrose; Fibrosis; Hypersensitivity pneumonitis; Pneumopathie d’hypersensibilité; Poumon de fermier