A misleading form of hypersensitivity pneumonitis

A 47-year-old woman, without significant past medical history, presented an acute dyspnea with hypoxia, marked pulmonary arterial hypertension (PAH) a nd signs of right heart failure. Chest x-ray showed a moderate dilatation o f the right heart cavities. Pulmonary embolism was suggested. After detaile d questioning and complete explorations, a bird hypersensitivity pneumoniti s (NP) was demonstrated. This case illustrates a misleading presentation of an acute form of HP consisting of apparently isolated PAH.